M+O Sensors: Monitoring & Optimization
Imagine automatic monitoring of equipment condition and performance, piping and vessel integrity, potential threats and escalation factors, as well as potential causes of process upsets and off-spec product. Imagine ability to optimize the time of equipment parts replacement, overhaul, cleaning of heat transfer surfaces, and pipe section replacement. Imagine being able to optimize the rate of anti-fouling chemical injection, and corrosion inhibitor injection, or the crude blend. It starts by automating the collection of the data that underpins the decisions and actions that make plants more reliable, sustainable, effective, and safer. You need many advanced sensors for monitoring and optimization (M+O). But with so many sensors available, how do you select? What is the recommended practice? Sensors are not the same, and wireless sensor networks are not the same either, so there are many important selection criteria. Here are my personal thoughts:
Digital transformation is about doing things differently, doing better. Doing something differently often starts with new information. To do better you need new information in your decision process. Think about it, when we regret some action, we often think to ourselves something like “had I only known that, I would have done it differently”. Therefore information is so important. That is why most Digitalization use-cases revolve around sensors.
Do you ‘get’ data?
You can’t predict something from nothing. Analytics cannot predict without real-time data. Software must see a small change somewhere indicating something is going to happen in the future. If there is no change measured, there is no prediction. Software must see an early symptom to predict something will happen. But once software sees these early symptoms, it can diagnose the problem so personnel can act to prevent it from escalating to outright failure. If you catch a slight increase in vibration early you have predicted bearing failure and have time to lubricate and align avoiding bearing and machine failure. If you catch faster wall thinning in piping you have predicted pipe failure and have time to inject more corrosion inhibitor to avoid loss of containment. If you catch faster decrease in heat transfer in a heat exchanger you have predicted fouling and have time to inject more anti-fouling chemicals to improve efficiency and avoid plugging. Better data means better predictions. Additional sensors mean earlier prediction, more precise description and prescription, and fewer false positives and false negatives.
If there is no change measured, there can be no prediction.
Missing Measurements
Today manual data collection is standing in the way of plants achieving their goal of greater availability, sustainability, safety, and agility. No one person has all these problems, it is spread across multiple departments. But everyone has some challenge. Manual data collection rounds mean missing measurements: long periods of time between updates or no measurements at all. Although plants have lots of sensors connected to their DCS or PLC for the core process control (CPC), these sensors are not sufficient for state-of-the-art operation. Missing measurements due to infrequent manual data collection or not at all, include:
Because these measurements were made manually or not at all, these positions are not seen on the automation piping and instrumentation diagrams (P&ID). Plants don’t have the data they need, in any system. So just connecting the existing systems together into a common platform is not sufficient. What plants now need are sensors Beyond the P&ID, sensors for monitoring and optimization beyond the core process control to get the missing measurements. Process equipment will be kitted out with wireless instrumentation.
Plants don’t have the data they need
Sensors for M+O
Plants are now automating previously manual data collection and interpretation tasks associated with reliability, sustainability (energy efficiency and emissions), occupational health and safety, as well as tasks around production and quality, by installing more sensors.
Measurements for M+O which plants now want to automate with permanent sensing include:
Your instrument engineers know how to specify these sensors for each use-case to make sure equipment are fully and correctly instrumented. Your automation vendor can also help.
Sense what has not been sensed before
Apart from driving action, information obtained by analytics from sensor data ultimately also ends up on dashboards.
The sensors used for monitoring and optimization are called M+O sensors or sometimes IIoT sensors. See the NAMUR NE183 standard. IIoT is a special case where measurements from machines (industrial things) are sent to the cloud (across the internet), but in most plants data is mostly stored and analyzed on premises. Plants usually select sensors which are wireless and non-intrusive, so the installation cost is low because wireless means there are no power cords or signal wires required to be laid, no conduits, no junction boxes, and no IO cards. Non-intrusive sensors meaning there is no cutting, drilling, or welding required for installation. Other sensors use existing process connection so there is no need to create a new process penetration. Most sensors can therefore be deployed while the plant is running. Non-intrusive also simplifies maintenance and reduces possible leak points.
The main part of this essay covers recommendations for each type of sensor. Some recommendations are common for many sensor types so there is some repetition, but it is important it is not lost when specifying that type of sensor. Like the chorus of a song.
The result is reduced downtime and maintenance cost, improved sustainability and reduced energy cost, greater safety, and reduced off-spec product to name a few.
But this automation also reduces cost of the data collection, particularly offshore and other remote locations where the cost of transportation and lodging of personnel is very high. Finally, it keeps people out of harm’s way.
NAMUR Open Architecture (NOA)
In the NAMUR Open Architecture (NOA) for the Fourth Industrial Revolution (4IR), these new sensors belong in the monitoring and optimization (M+O) security zone, independent of the core process control (CPC) security zone.
One of many advantages of this arrangement is that software apps and sensors for M+O can be added one-by-one any time building this Digital Operational Infrastructure (DOI) in a phased approach without impact to the safety and robustness of the DCS in the CPC security zone. That is, in the M+O security zone, you can add apps and sensors without the same rigor of management of change (MoC) as for the DCS and SIS. Thus NOA provide flexibility to add M+O use cases while preserving the robustness and safety of the DCS and SIS.
Monitoring (for Prevention)
Prevention is the intent of monitoring. That is, personnel use real-time information to drive action that prevents problems like equipment failure and inefficiency, loss of containment, spills and fire, product cross contamination, flaring and loss, injury, overconsumption, and off-spec product.
Prevention is the intent of monitoring.
‘Monitoring’ includes measurement, visualization, time-series trending, alarm, and often analytics.
When an event has already occurred you can't measure what happened in the past to understand what led to the event. What you therefore need is continuous monitoring of vibration, temperature, acoustic noise, and others using transmitters and logging this data much like a flight data recorder (black box) in an airplane. With sensors in place, you get an early warning allowing you to take action to avoid the problem in the first place. If the problem like failure still occurs, you at least have the data you can go back and study in a postmortem to understand the events that led up to the failure so you can learn to avoid it in the future.
Process data is not enough. Without equipment data, equipment failure and performance degradation cannot be predicted.
Optimization
Optimization means striking the optimum balance between conflicting goals. That is, personnel use real-time information to decide when the best time is to perform a task or what the best setpoint is. For instance:
M+O Sensor Performance
When you are replacing mechanical pressure gauges having 2% accuracy plus parallax error, new electronic sensors having an accuracy of 0.5% and no parallax error is more than sufficient, and a great improvement. So in many cases the wireless sensors you use for M+O or IIoT can be lower performance than their process control counterparts. However, this does not mean all wireless sensors are low performance. The most interesting fact is that you can get wireless sensors which are just as good as your wired sensors. In fact, the sensor is the same. The only difference is the transmitter. So if you want wireless pressure measurement with 0.025% accuracy, 0.035%/28°C ambient temperature stability, 15-year stability, and 15 years of warranty just like your wired devices, you can. And there are use cases where you want that level of performance from your wireless sensors. But such a sensor cost more than those with lower performance.
M+O Sensor Price
Many M+O sensors are non-intrusive, which also means they are not wetted by the process. Such sensors do not have large flanges and no exotic materials so they are in some cases smaller and lower price than sensors that are in contact with the process. However, industrial sensors are not as cheap as chips for several reasons. What makes M+O sensors so cost-effective is that they are wireless and non-intrusive as explained above. Sensors with lower accuracy and stability are lower cost than sensors with higher performance. Advanced sensors like vibration and ultrasonic thickness (UT) are very sophisticated and therefore an order of magnitude more expensive than other sensors.
Vibration
Most plants have online vibration monitoring systems for condition monitoring of their critical rotating machinery like large turbomachinery such as gas turbines, steam turbines, and centrifugal compressors. However, for other rotating equipment most plants still rely on periodic manual testing using portable vibration testers. With the large number of rotating equipment in a plant, personnel and external contractors are unable to test every piece of equipment frequently. Due to infrequent testing, for example monthly, signs of developing issues are missed because bearings can deteriorate suddenly, much faster than that, and sometimes equipment therefore fail unexpectedly causing production downtime and associated opportunity cost, as well as repair cost.
The solution is instrumentation: permanently installed vibration sensors. What used to be portable and manual, is now permanent and automatic.
Vibration measurement is used mainly for condition monitoring of rotating equipment like motors, pumps, compressors, fans/blowers such as in air cooled heat exchangers, gear boxes such as in cooling towers, and conveyor belts etc. By picking up on small changes in bearing vibration symptoms that appear when there is lack of lubrication, parts are loose, or misaligned etc. software can predict trouble will occur if action is not taken, long before failure. Thanks to vibration sensors, analytics software provides early notifications which tell the maintenance team that lubrication, alignment, or part replacement is required.
By the time bearing vibration is picked up by a process sensor, the problem has gone too far, therefore process data is not sufficient for equipment failure prediction.
Yet equipment has many failure modes with various other symptoms like temperature increase, noise, or pressure instability. Therefore, full equipment condition monitoring requires additional sensors as well.
Vibration sensing alone is not sufficient to predict all equipment problems. Predicting more failure modes requires more sensors.
Beyond reducing data collection cost and keeping people out of harm’s way, permanent vibration measurement thus helps avoid equipment failure, production downtime and associated opportunity cost, as well as repair cost.
Vibration sensors are not all the same. There are significant differences in capabilities between various offerings. Therefore select vibration sensors carefully. All vibration sensors provide the basic measurement of overall vibration (velocity). The recommendation is to use vibration sensors which also has embedded analytics (edge-analytics) for peak value (acceleration). Peak value goes beyond Fast Fourier Transform (FFT) and detects stress to discover developing rolling element bearing issues sooner. Earlier detection is critical to be able to prevent problems from materializing. Peak value is a simple variable which makes analytics (diagnostics) very easy enabling robust rule-based cause & effect type of Artificial Intelligence (AI). Peak value reduces data transmitted by hourly sending only the simple variable, not the full waveform and spectrum, thereby extending battery life in wireless sensors which is important, reducing bandwidth requirements which is important in remote applications where bandwidth is limited and costly. The full waveform and spectrum are only transmitted when there is developing problem to enable root cause analysis. Wireless vibration sensors tend to have shorter battery life than other wireless sensors. Make sure to use wireless vibration sensors that support a 1-hour update period, and provide a 3-5 year battery life at 1 hour update period.
Detail analysis of vibration waveform and spectrum is key to root cause analysis of vibration problems. That is, just periodic update of the overall vibration velocity value is not sufficient. It must also be possible to retrieve the vibration waveform and spectrum on demand any time. Many wireless sensor network technologies only support periodic updates of simple measurements, not on-demand communication of large data sets. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART supports on-demand communication of large data sets like vibration waveforms and spectrums. The recommendation is therefore to deploy wireless sensor network infrastructure and vibration sensors based on the WirelessHART standard IEC62591. Measured values are transmitted with status and engineering unit. The WirelessHART gateway makes the measurements available as OPC-UA, Modbus, and HART-IP. This is critical to make the data easy to handle.
[Chorus] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and vibration sensors based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
Ultrasonic Thickness (UT)
Most plants still rely on periodic manual testing using portable ultrasonic thickness (UT) testers for corrosion and erosion of vessels and pipe walls to know their integrity. With the large number of vessels and long pipe runs in a plant, personnel and external contractors are unable to inspect every position frequently. Due to infrequent checks, for example yearly data collection, signs of developing issues are missed because corrosion rate can suddenly get worse due to change in feedstock, and sometimes piping therefore fail unexpectedly causing loss of containment, possibly fire and explosion, production downtime and associated opportunity cost, as well as replacement cost.
The solution is instrumentation: permanently installed ultrasonic thickness sensors. What used to be portable and manual, is now permanent and automatic.
Ultrasonic thickness measurement is used for corrosion and erosion monitoring of pipes and vessels. UT sensors are typically installed in pipe elbows and other spots that experience greater corrosion and erosion. By picking up on gradual changes in wall thickness due to corrosion and erosion such as when more corrosive feedstock is used or insufficient corrosion inhibitor is injected, software can predict when pipe sections need to be replaced. Thanks to UT sensors, analytics software determines the corrosion rate which enables optimization by revealing to the operations team that corrosion inhibitor injection must be increased or can be decreased, that the crude blend can or must be adjusted, and the maintenance team can estimate when the pipe section must be replaced. Because UT measures thickness in a single point, multiple UT sensors are sometimes used to measure the corrosion for multiple points around the circumference of a pipe. The points where you used to manually measure thickness, is where permanent UT sensors are installed.
Beyond reducing data collection cost and keeping people out of harm’s way, permanent thickness measurement quantifies metal loss and thus helps avoid loss of containment, production downtime and associated opportunity cost, as well as repair cost. And it reduces the risk of fires and explosions.
UT sensors are not all the same. There are significant differences in capabilities between various offerings. Therefore select UT sensors carefully. The recommendation is to use UT sensors which provide data to enable analytics to also determine internal pipe surface roughness.
UT sensors are non-intrusive, clamping onto the outside of the pipe, meaning there is no cutting, drilling, or welding required for installation providing a cost-effective implementation. UT sensors can therefore be deployed while the plant is running.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and UT sensors based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
Acoustic
Most plants still rely on periodic manual testing using portable ultrasound and temperature testers to survey steam traps and pressure relief valves (PRV) to know their health. With the large number of steam traps and PRVs in a plant, personnel and external contractors are unable to inspect every one frequently. Due to infrequent checks, for example yearly data collection, failed steam traps go unnoticed for long periods of time causing steam loss which is a significant cost for such long periods, as well as in other cases causing off-spec product due to insufficient heating, or condensate water hammer resulting in pipe and flange damage. PRVs stuck open, passing, simmering, or lifting too early cause product loss and flaring.
The solution is instrumentation: permanently installed acoustic sensors. What used to be portable and manual, is now permanent and automatic.
Acoustic noise measurement together with temperature measurement is used mainly for monitoring the health of steam traps and status of PRVs. By picking up ultrasound noise such as due to PRV release, simmering, or passing while shut, or ultrasound noise from steam traps during their operation, software can tell from the noise pattern and temperature if the steam trap is operating correctly or if the PRV is releasing, simmering, or passing. Thanks to acoustic sensors, analytics software provides early notifications which tells the maintenance team when a steam trap needs replacement or a PRV needs overhaul. It also positively timestamps releases so release volumes can be calculated more accurately, and releases can be correlated to process events to help identify the root cause of overpressure such that changes can be made to reduce the occurrence of overpressure in the first place. And there are many other applications such as boiler tube leaks and air trap health.
Beyond reducing data collection cost and keeping people out of harm’s way, permanent acoustic noise measurement identifies steam loss and product loss to flare and thus helps reduce energy cost and other production cost. Carbon footprint is also reduced.
Acoustic sensors are not all the same. There are significant differences in capabilities between various offerings. Therefore select acoustic sensors carefully. The recommendation is to use acoustic sensors which can optionally be set with fast update period of only a few seconds to capture short PRV releases.
Acoustic sensors are non-intrusive, clamping onto the outside of the pipe, meaning there is no cutting, drilling, or welding required for installation providing a cost-effective implementation. Acoustic sensors can therefore be deployed while the plant is running.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and acoustic sensors based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
Measured values are transmitted with status and engineering unit.
Pressure
Most plants still rely on periodic field operator rounds reading mechanical pressure gauges and manually recording data in a paper form on a clipboard or in a mobile digital device like a tablet. With the large number of mechanical pressure gauges in a plant, personnel are unable to go read pressure gauges frequently. Due to infrequent rounds, for example daily, weekly, or monthly data collection, pressure drops and increases go unnoticed for long periods of time and short intermittent pressure changes are not caught at all. Depending on the use-case for the pressure gauge, not capturing a change in pressure can result in all sorts of problems such as running out of (gaseous) consumables, equipment damage, ineffective fire suppression, and other risks.
The solution is instrumentation: electronic pressure gauges or pressure sensors. What used to be periodic and manual, is now real-time and automatic.
Pressure measurement is used for optimization of gaseous consumables inventory replenishment, not too early and not too late, and for monitoring equipment lube oil pressure, fire hydrant line pressure, compressed air system, and many other fluid pressures not directly related to the control of the process but important to the availability of the production and the safety of the plant. Also suitable for mechanical seal reservoir pressure which today may use pressure switch but for which the 2014 edition of API standard 682 instead recommends pressure transmitter.
Because these sensors are electronic, having no moving parts, they are more reliable than bourdon tube pressure gauges.
Beyond reducing data collection cost and keeping people out of harm’s way, real-time pressure measurement thus helps avoid equipment failure, production downtime and associated opportunity cost, as well as repair cost. Real-time pressure measurement also helps avoid threat escalation factors like the fire suppression systems being depressurized.
[Chorus] Wireless sensor network technologies are not all the same. There are significant differences in capabilities between various technologies. Therefore select wireless sensor network technology carefully. Pressure sensors are often used in use-cases where the pressure shall be displayed in an HMI, dashboards, or be used in some form of analytics software, even displayed in the historian or DCS in some plant philosophies. Many wireless sensor network technologies do not define a standard data format meaning coding/scripting specific to each type of sensor is required to integrate the data into third-party systems. When the sensor is replaced this coding/scripting must again be redone. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART defines a standard data format so sensors for pressure, temperature, level, and flow etc. work the same way. This enables a WirelessHART gateway to automatically convert data into OPC-UA, HART-IP, and Modbus/TCP protocols etc. to bring data into third-party software by simply selecting desired data points, without the need for coding/scripting. This also makes future device replacement easier. The recommendation is to deploy wireless sensor network infrastructure based on the WirelessHART standard IEC62591. Measured values are transmitted with status and engineering unit.
A wireless pressure sensor optionally comes with an LCD indicator for local numerical display useful when working in the field. A wireless pressure gauge comes with dial card and pointing needle for a more visual display that can even be seen from a distance. The recommendation is to use wireless pressure gauges whenever replacing mechanical pressure gauges.
Some pressure sensor models can optionally be set with fast update period of only a few seconds to capture sudden pressure changes.
Pressure sensors can reuse the existing process connections until now used by mechanical pressure gauges. In this case there is no need to create a new process penetration. If the process connection has an instrument valve, a pressure sensor can be deployed while the plant is running.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and pressure sensors based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
[Chorus] Instrument technicians are very familiar with the standard HART field communicator also used for your 4-20 mA/HART devices. The recommendation is therefore to use wireless pressure sensors or gauges with a HART communication maintenance/console port (grabber hook terminals) to enable calibration locally while you are venting or applying pressure to the sensor or gauge.
[Chorus] Returning to a sensor or gauge in the field to verify the configuration is correct, has not been tampered with, or to make changes would be time consuming. The recommendation is therefore to use wireless sensors and gauges using the WirelessHART protocol as this allows over-the-air configuration (parameterization), such as pressure unit, to be checked and changed from a central location from Intelligent Device Management (IDM) software or a simple device configurator software. Many other wireless sensor network technologies do not support central configuration changes this way.
Corrosivity
Most plants still rely on periodic manual retrieval of Weight Loss Coupons (WLC) to know the corrosivity of fluids in their piping systems. Retracting/retrieving corrosion coupons, bringing them to the lab, cleaning, weighing, interpreting the data, and returning them to the field and reinstalling them is labor intensive. With the large number of positions in a plant, personnel and external contractors are unable to retrieve and inspect every position frequently. These positions may be hard to reach, at height, near hot surfaces, and are pressurized. Due to infrequent checks, for example yearly weighing, signs of developing issues are missed because corrosion rate can suddenly get worse due to change in feedstock, and sometimes piping therefore fail unexpectedly causing loss of containment, possibly fire and explosion, production downtime and associated opportunity cost, as well as replacement cost.
The solution is instrumentation: electronic inline Electrical Resistance (ER) probe or Linear Polarization Resistance (LPR) sensors. What used to be periodic and manual, is now real-time and automatic.
ER/LPR measurement is used for corrosivity monitoring of fluids in pipes, picking up on changes in corrosivity (mm/year) such as when more corrosive feedstock is used or insufficient corrosion inhibitor is injected. ER/LPR sensors enable optimization of corrosion inhibitor injection by revealing to the operations team if corrosion inhibitor injection must be increased or can be decreased, that the crude blend can or must be adjusted. An inline ER/LPR probe is ideal for fluid corrosivity measurement with high sensitivity and fast response to optimize corrosion inhibitor injection.
Beyond reducing data collection cost and keeping people out of harm’s way, real-time corrosivity measurement quantifies metal loss and thus helps avoid accelerated corrosion, associated risks of loss of containment, replacement cost, and downtime.
[Repeat] Wireless sensor network technologies are not all the same. There are significant differences in capabilities between various technologies. Therefore select wireless sensor network technology carefully. ER/LPR sensors could be used in use-cases where the corrosion rate shall be displayed in an HMI, dashboards, even displayed in the historian or DCS in some plant philosophies. Many wireless sensor network technologies do not define a standard data format meaning coding/scripting specific to each type of sensor is required to integrate the data into third-party systems. When the sensor is replaced this coding/scripting must again be redone. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART defines a standard data format so sensors work the same way. This enables a WirelessHART gateway to automatically convert data into OPC-UA, HART-IP, and Modbus/TCP protocols etc. to bring data into third-party software by simply selecting desired data points, without the need for coding/scripting. The recommendation is to deploy wireless sensor network infrastructure based on the WirelessHART standard IEC62591. Measured values are transmitted with status and engineering unit.
Insertion corrosion coupons are replaced with inline ER probe or LPR probe that fit in the position where the corrosion coupon used to sit. This makes installation easy and low cost; no additional process penetration required when an existing position is used. Depleted ER/LPR probes can be retracted and replaced while the plant is running.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. Therefore the recommendation is to deploy wireless sensor network infrastructure and ER/LPR sensors based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
Differential Pressure (DP)
Most plants still rely on periodic field operator rounds reading variable area (VA) flow meters and level sight glasses, manually recording data in a paper form on a clipboard or in a mobile digital device like a tablet. With the large number of variable area flow meters and level sight glasses in a plant, personnel are unable to go read them frequently. Due to infrequent rounds, for example daily, weekly, or monthly data collection, flow and level changes go unnoticed for long periods of time and short intermittent changes are not caught at all. Depending on the use-case for the variable area flow meters and level sight glasses, not capturing a change can result in all sorts of problems such as running out of (liquid) consumables, equipment damage, and other risks.
The solution is instrumentation: electronic differential pressure (DP) or ΔP sensors. What used to be periodic and manual, is now real-time and automatic.
DP sensors are used to measure pressure drop, flow, and liquid level. Every instrument engineer knows how to do this. DP level measurement is used for optimization of liquid consumables inventory replenishment, and monitoring equipment lube oil level, coolant level, and many other fluid levels not directly related to the control of the process but important to the availability of the production. Also suitable for mechanical seal flush fluid level which today may use level switch but for which the 2014 edition of API standard 682 instead recommends level transmitter. DP is also a common method of flow measurement in conjunction with orifice plate, pitot tube, or other DP producers. DP flow measurement is used for monitoring consumption of utilities such as water, compressed air, fuel gas, steam, and many other utility liquid and gases for ISO50001 energy management such as energy cost accounting, leak detection, and overconsumption detection to improve sustainability. But also for many other fluid flows not directly related to the control of the process but important to ensure equipment performance. Plain DP measurement is used for pressure drop across filters, strainers, heat exchangers, and other equipment to quantify blockage/plugging to enable optimization of the time of cleaning of filters and strainers, to maintain efficiency by cleaning to reduce pressure drop, yet minimize process downtime for cleaning.
Beyond reducing data collection cost and keeping people out of harm’s way, real-time DP measurement thus helps avoid energy overconsumption, equipment failure, production downtime, and associated opportunity cost.
[Repeat] Wireless sensor network technologies are not all the same. There are significant differences in capabilities between various technologies. Therefore select wireless sensor network technology carefully. DP sensors are often used in use-cases where the DP, level, or flow shall be displayed in an HMI, dashboards, or be used in some form of analytics software, even displayed in the historian or DCS in some plant philosophies. Many wireless sensor network technologies do not define a standard data format meaning coding/scripting specific to each type of sensor is required to integrate the data into third-party systems. When the sensor is replaced this coding/scripting must again be redone. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART defines a standard data format so sensors for DP, level, and flow etc. work the same way. This enables a WirelessHART gateway to automatically convert data into OPC-UA, HART-IP, and Modbus/TCP protocols etc. to bring data into third-party software by simply selecting desired data points, without the need for coding/scripting. This also makes future device replacement easier. The recommendation is to deploy wireless sensor network infrastructure based on the WirelessHART standard IEC62591. Measured values are transmitted with status and engineering unit.
A wireless DP sensor optionally comes with an LCD indicator for local display useful when working in the field.
Some pressure sensor models can optionally be set with fast update period of only one second to capture sudden changes in flow.
For DP flow measurement the recommendation is to use compact orifice plate which can be installed simply by prying pipe flanges apart and slipping the orifice assembly between the flanges. With a conditioning orifice plate, only two pipe-diameters of upstream and downstream straight pipe-run is required making the installation easy and compact.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and DP sensors based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
[Repeat] Instrument technicians are very familiar with the standard HART field communicator also used for your 4-20 mA/HART devices. The recommendation is therefore to use wireless DP sensors with a HART communication maintenance/console port (grabber hook terminals) to enable calibration locally while you are venting or applying pressure to the sensor.
[Repeat] Returning to a sensor in the field to verify the configuration is correct, has not been tampered with, or to make changes would be time consuming. The recommendation is therefore to use wireless sensors using the WirelessHART protocol as this allows over-the-air configuration (parameterization) such as pressure unit, transfer function (linear or square root), and damping to be checked and changed from a central location from Intelligent Device Management (IDM) software or a simple device configurator software. Many other wireless sensor network technologies do not support central configuration changes this way. Scaled variable is also a required feature in DP sensors with digital output to convert from pressure units to flow units in DP flow applications to make the values easy to read for operators and other personnel.
Discrete Contact
Most plants still rely on periodic field operator rounds to check for open hatches, doors, and gates, and if equipment is running or not, rupture disks, signs of leaks, pressure/vacuum relief valves, and many other things and manually recording this in a paper form on a clipboard or in a mobile digital device like a tablet. In some plants people must themselves call if they are in distress, in need of assistance at a safety shower or eye wash station, and explain which one they are at. With the large number of inspection points, personnel are unable to go check frequently. Due to infrequent rounds, for example daily, weekly, or monthly inspection, unwanted situations go unnoticed for long periods of time and near-misses don’t get reported. Depending on the use-case, not noting which state something is in can result in all sorts of problems such as gas emissions, unauthorized intrusion, production interruption, equipment failure, or injury.
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The solution is instrumentation: primary sensors together with a wireless discrete contact transmitter. What used to be periodic and manual, is now real-time and automatic.
The primary sensor is usually a proximity switch or limit switch but can also be a specialized plunger arrival sensor, hydrocarbon or chemical sensor, burst disc indicator, reed switch, or a relay etc. Just about anything with a ‘dry contact’ output. The primary sensor output contact is connected to the wireless discrete contact transmitter. These solutions are used for monitoring in many applications:
Discrete contact transmitters are also used together with pressure, flow, and level switches to transmit the status wirelessly instead of laying cable. However, it should be noted that these days plants tend to use wireless pressure, flow, and level transmitters instead of switches.
On-off valve position sensing discussed separately below.
Beyond reducing data collection cost and keeping people out of harm’s way, real-time status updates thus helps avoid injury, pollution, emissions, unauthorized access, and equipment damage etc.
[Repeat] Wireless sensor network technologies are not all the same. There are significant differences in capabilities between various technologies. Therefore select wireless sensor network technology carefully. These signals are often used in use-cases where the status shall be flagged in an HMI, dashboards, even flagged in the historian or DCS in some plant philosophies. Many wireless sensor network technologies do not define a standard data format meaning coding/scripting specific to each type of sensor is required to integrate the data into third-party systems. When the discrete contact transmitter is replaced this coding/scripting must again be redone. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART defines a standard data format so sensors work the same way. This enables a WirelessHART gateway to automatically convert data into OPC-UA, HART-IP, and Modbus/TCP protocols etc. to bring data into third-party software by simply selecting desired data points, without the need for coding/scripting. This also makes future device replacement easier. The recommendation is to deploy wireless sensor network infrastructure based on the WirelessHART standard IEC62591.
A wireless discrete contact transmitter optionally comes with an LCD indicator for local display useful when working in the field.
A fast update period of only one second can be set to capture sudden changes.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and discrete contact transmitters based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
[Repeat] Returning to a discrete contact transmitter in the field to verify the configuration is correct, has not been tampered with, or to make changes would be time consuming. The recommendation is therefore to use wireless discrete contact transmitters using the WirelessHART protocol as this allows over-the-air configuration (parameterization), such as direct or inverse logic, to be checked and changed from a central location from Intelligent Device Management (IDM) software or a simple device configurator software. Many other wireless sensor network technologies do not support central configuration changes this way.
The discrete contact transmitter can also count the number of close-open cycles.
Note that leak detection and plunger arrival sensors are not simple contact closures (‘dry contact’) so make sure to use discrete contact transmitter with such capability.
The discrete contact transmitter is dual channel because many use-cases involve two proximity switches such as for open and closed position, safety shower and eye-wash status, and pressure and vacuum side etc.
Position
Most plants still need to callout a field operator to check on the position of manual on-off valves when starting up or shutting down a unit, loading or offloading, and for other operations requiring manual valve lineup, bypass, or isolation etc. Sometimes the manual valves are not checked, or the wrong valve is checked. A manual valve in the wrong position or not shut tightly can result in all sorts of problems such as product cross contamination, overfill, spill, fire, explosion, and injury.
The solution is instrumentation: a limit switch box or proximity switches together with a wireless discrete contact transmitter. What used to be manual, is now automatic.
A limit switch box is used for quarter turn on-off valves. For linear multi-turn on-off valves two separate proximity switches are used. The two limit switches or proximity switches are connected to the dual input wireless discrete contact transmitter together monitoring the valve position.
Beyond reducing data collection cost and keeping people out of harm’s way, real-time on-off valve position sensing thus helps avoid injury, pollution, emissions, and product cross contamination etc.
Embedded logic determines if the valve is open, closed, or in between such as during travel or if not fully opened or not tightly shut.
[Repeat] Wireless sensor network technologies are not all the same. There are significant differences in capabilities between various technologies. Therefore select wireless sensor network technology carefully. These signals are often used in use-cases where the valve position shall be displayed in an HMI, dashboards, even displayed in the historian or DCS in some plant philosophies. Many wireless sensor network technologies do not define a standard data format meaning coding/scripting specific to each type of sensor is required to integrate the data into third-party systems. When the discrete contact transmitter is replaced this coding/scripting must again be redone. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART defines a standard data format so sensors work the same way. This enables a WirelessHART gateway to automatically convert data into OPC-UA, HART-IP, and Modbus/TCP protocols etc. to bring data into third-party software by simply selecting desired data points, without the need for coding/scripting. This also makes future device replacement easier. The recommendation is to deploy wireless sensor network infrastructure based on the WirelessHART standard IEC62591.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and position monitoring solutions based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
Guided Wave Radar Level
Most plants still rely on periodic field operator rounds reading level sight glasses, magnetic level gauges, or even using dipstick, and then manually recording data in a paper form on a clipboard or in a mobile digital device like a tablet. With the large number of level sight glasses in a plant, personnel are unable to go read sight glasses frequently. Due to infrequent rounds, for example daily, weekly, or monthly data collection, level changes go unnoticed for long periods of time. Depending on the use-case for the sight glass, not capturing a change in level can result in all sorts of problems such as running out of (liquid) consumables, equipment damage, overfill, and other risks. In some cases field operators standby at the tank or pond with a walkie-talkie during filling operations which is not productive.
The solution is instrumentation: electronic level sensors. What used to be periodic and manual, is now real-time and automatic.
Level measurement is used for optimization of liquid consumables inventory replenishment, and monitoring equipment lube oil level, and many other liquid levels, often not directly related to the control of the process but important to the availability of the production. Other use-cases include tank overfill prevention and tank floating roof tilt detection. These use-cases apply to storage, buffer, and tote tanks. Waste tanks and sumps. Remote ponds, reservoirs, and bunds/dikes/dykes. Also suitable for mechanical seal flush fluid level measurement which today may use level switches but for which the 2014 edition of API standard 682 instead recommends level transmitter. Guided wave radar (GWR) can measure both level and interface level such as in separators.
DP level is another approach to measure liquid level suitable for some level applications as explained above at Differential Pressure.
Beyond reducing data collection cost and keeping people out of harm’s way, real-time level measurement thus helps prevent overfill, avoid equipment failure, production downtime and associated opportunity cost, as well as repair cost.
[Repeat] Wireless sensor network technologies are not all the same. There are significant differences in capabilities between various technologies. Therefore select wireless sensor network technology carefully. Level sensors are often used in use-cases where the level shall be displayed in an HMI, dashboards, or be used in some form of analytics software, even displayed in the historian or DCS in some plant philosophies. Many wireless sensor network technologies do not define a standard data format meaning coding/scripting specific to each type of sensor is required to integrate the data into third-party systems. When the sensor is replaced this coding/scripting must again be redone. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART defines a standard data format so sensors for pressure, temperature, level, and flow etc. work the same way. This enables a WirelessHART gateway to automatically convert data into OPC-UA, HART-IP, and Modbus/TCP protocols etc. to bring data into third-party software by simply selecting desired data points, without the need for coding/scripting. This also makes future device replacement easier. The recommendation is to deploy wireless sensor network infrastructure based on the WirelessHART standard IEC62591. Measured values are transmitted with status and engineering unit.
A wireless level sensor optionally comes with an LCD indicator for local display useful when working in the field.
Some level sensor models can optionally be set with fast update period of only a few seconds to capture rapid level changes.
Level sensors can often reuse the existing process connections until now used by level sight glasses such as a bridle chamber. Tank tops may have unused flanges. In this case there is no need to create a new process penetration.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and level sensors based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
[Repeat] Instrument technicians are very familiar with the standard HART field communicator also used for your 4-20 mA/HART devices. The recommendation is therefore to use wireless level sensors with a HART communication maintenance/console port (grabber hook terminals) to enable calibration locally while you verify the level.
[Repeat] Returning to a sensor in the field to verify the configuration is correct, has not been tampered with, or to make changes would be time consuming. The recommendation is therefore to use wireless sensors using the WirelessHART protocol as this allows over-the-air configuration (parameterization), such as level, volume, and temperature units, tank geometry, and process fluids (dielectric constant) to be checked and changed from a central location from Intelligent Device Management (IDM) software or a simple device configurator software. Many other wireless sensor network technologies do not support central configuration changes this way.
Temperature
Most plants still rely on periodic field operator rounds reading mechanical temperature gauges and manually recording data in a paper form on a clipboard or in a mobile digital device like a tablet. Similarly, most plants still rely on periodic manual testing using portable infrared (IR) temperature guns or portable thermal imaging cameras. With the large number of mechanical temperature gauges in a plant, personnel are unable to go read temperature gauges frequently. And for the same reason, they are unable to test every piece of equipment with a temperature gun. Due to infrequent rounds, for example daily, weekly, or monthly data collection, signs of developing issues are missed as temperature changes go unnoticed for long periods of time and sudden temperature changes are not caught at all. Depending on the use-case for the temperature gauge, not capturing a change in temperature can result in all sorts of problems such as equipment damage and other risks.
The solution is instrumentation: electronic temperature sensors. What used to be periodic and manual, is now real-time and automatic.
Temperature measurement is used for monitoring equipment lube oil and coolant temperature, bearing and motor winding overheating, as well as temperature of surfaces that could cause ignition of flammable gases, and many other temperatures not directly related to the control of the process but important to the availability of the production and the safety of the plant. Temperature measurement is also used for detecting gas leaks (Joules-Thomson effect).
Because these sensors are electronic, having no moving parts, they are more reliable that bimetallic temperature gauges.
Beyond reducing data collection cost and keeping people out of harm’s way, real-time temperature measurement thus helps avoid equipment failure, production downtime and associated opportunity cost, as well as repair cost. Gas leaks with associated risks, losses, and emissions are also reduced.
[Repeat] Wireless sensor network technologies are not all the same. There are significant differences in capabilities between various technologies. Therefore select wireless sensor network technology carefully. Temperature sensors are often used in use-cases where the temperature shall be displayed in an HMI, dashboards, or be used in some form of analytics software, even displayed in the historian or DCS in some plant philosophies. Many wireless sensor network technologies do not define a standard data format meaning coding/scripting specific to each type of sensor is required to integrate the data into third-party systems. When the sensor is replaced this coding/scripting must again be redone. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART defines a standard data format so sensors for pressure, temperature, level, and flow etc. work the same way. This enables a WirelessHART gateway to automatically convert data into OPC-UA, HART-IP, and Modbus/TCP protocols etc. to bring data into third-party software by simply selecting desired data points, without the need for coding/scripting. This also makes future device replacement easier. The recommendation is to deploy wireless sensor network infrastructure based on the WirelessHART standard IEC62591. Measured values are transmitted with status and engineering unit.
Permanent temperature sensors provide direct numerical value direct into time-series trend, alarm, and display without human interpretation of photos or video.
A wireless temperature sensor optionally comes with an LCD indicator for local display useful when working in the field. Local display is good for wireless sensors taking the place of mechanical gauges.
Some temperature sensor models can optionally be set with fast update period of only a few seconds to capture sudden temperature changes.
Temperature sensors, the primary element like thermocouple or resistance temperature detector (RTD), can reuse the existing process connections until now used by mechanical temperature gauges. In this case there is no need to create a new process penetration. If the process connection has a thermowell, a temperature sensor can be inserted while the plant is running. Another non-intrusive option for pipes is to use a clamp-on skin temperature sensor that measures the surface temperature of the pipe which for many use-cases is a sufficient approximation. There is no cutting, drilling, or welding required for installation providing a cost-effective implementation. This also eliminates the complications associated with calculating and installing thermowells.
More advanced temperature transmitters have taken non-intrusive skin temperature monitoring even further. They measure both the pipe skin temperature and the ambient temperature at the terminal block. Using a thermal conductivity algorithm and the conductive properties of the pipe, the algorithm accurately calculates the internal process temperature.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and temperature sensors based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
[Repeat] Instrument technicians are very familiar with the standard HART field communicator also used for your 4-20 mA/HART devices. The recommendation is therefore to use wireless temperature sensors with a HART communication maintenance/console port (grabber hook terminals) to enable calibration locally while you are simulating from a calibrator or dry block by the transmitter.
[Repeat] Returning to a sensor in the field to verify the configuration is correct, has not been tampered with, or to make changes would be time consuming. The recommendation is therefore to use wireless sensors using the WirelessHART protocol as this allows over-the-air configuration (parameterization), such as sensor type, connection, and temperature unit, to be checked and changed from a central location from Intelligent Device Management (IDM) software or a simple device configurator software. Many other wireless sensor network technologies do not support central configuration changes this way.
Multi-Temperature
Temperature difference (ΔT) is a particular challenge in plants because one person cannot measure temperature in two places at the same time. For instance, to compute equipment efficiency of you need to measure the inlet and outlet temperatures and calculate the difference. Since these temperatures are constantly fluctuating, the two temperatures must be measured at the same time, or else calculations will be wrong. You can’t do it manually so this is one reason it doesn’t get done. Thus plants cannot tell if their equipment is fouling. As a result they run inefficiently causing energy overconsumption or production bottlenecks.
Another challenge is that for process equipment plants rely on single-point temperature measurement although they know that by seeing the temperature profile of the equipment they could control the process better for a better chemical reaction or calculate the inventory more accurately.
The solution is instrumentation: multi-input temperature transmitters. What didn’t used to get measured, now is. What used to be a single spot measurement, is now a temperature profile.
Multi-point temperature measurement is used to quantify the efficiency of equipment like heat exchangers, cooling towers, and air-cooled heat exchangers etc. to optimize the time of cleaning to restore efficiency but without causing excessive downtime. Particularly of they have multiple bundles or multiple cells. Multi-point temperature measurement is also used to visualize the temperature profile of chemical reactors, columns/towers, furnaces, and reformers etc. as well as large storage tanks to optimize chemical reactions, separation, and other processes. A high-resolution temperature profile for a large piece of equipment may require several multi-point temperature transmitters.
Beyond reducing data collection cost and keeping people out of harm’s way, multi-point temperature measurement thus improves energy efficiency and sustainability, and reducing production downtime and associated opportunity cost, as well as cleaning cost.
A multi-input temperature transmitter samples four or more temperature inputs simultaneously to provide a true temperature difference taking care of the ΔT measurement challenge, for both hot and cold sides, for heat exchangers and other equipment. The recommendation is to deploy multi-input temperature transmitters rather than single-point transmitters in ΔT applications.
[Repeat] Wireless sensor network technologies are not all the same. There are significant differences in capabilities between various technologies. Therefore select wireless sensor network technology carefully. Multi-input temperature sensors are often used in use-cases where the temperatures such as a temperature profile shall be displayed in an HMI, dashboards, or be used in some form of analytics software, even displayed in the historian or DCS in some plant philosophies. Many wireless sensor network technologies do not define a standard data format meaning coding/scripting specific to each type of sensor is required to integrate the data into third-party systems. When the sensor is replaced this coding/scripting must again be redone. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART defines a standard data format so sensors for pressure, temperature, level, and flow etc. work the same way. This enables a WirelessHART gateway to automatically convert data into OPC-UA, HART-IP, and Modbus/TCP protocols etc. to bring data into third-party software by simply selecting desired data points, without the need for coding/scripting. This also makes future device replacement easier. The recommendation is to deploy wireless sensor network infrastructure based on the WirelessHART standard IEC62591. Measured values are transmitted with status and engineering unit.
Some multi-input temperature transmitter models can optionally be set with fast update period of only a few seconds to capture sudden temperature changes.
[Repeat] Temperature sensors, the primary element like thermocouple or resistance temperature detector (RTD), can reuse the existing process connections until now used by mechanical temperature gauges. In this case there is no need to create a new process penetration. If the process connection has a thermowell, a temperature sensor can be deployed while the plant is running. Another non-intrusive option for pipes is to use a clamp-on skin temperature sensor that measures the surface temperature of the pipe which for many use-cases is a sufficient approximation. There is no cutting, drilling, or welding required for installation providing a cost-effective implementation. This also eliminates the complications associated with calculating and installing thermowells.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and temperature sensors based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
[Repeat] Instrument technicians are very familiar with the standard HART field communicator also used for your 4-20 mA/HART devices. The recommendation is therefore to use wireless multi-input transmitters with a HART communication maintenance/console port (grabber hook terminals) to enable calibration locally while you are simulating from a calibrator or dry block by the transmitter.
[Repeat] Returning to a sensor in the field to verify the configuration is correct, has not been tampered with, or to make changes would be time consuming. The recommendation is therefore to use wireless sensors using the WirelessHART protocol as this allows over-the-air configuration (parameterization), such as sensor type, connection, and temperature unit, to be checked and changed from a central location from Intelligent Device Management (IDM) software or a simple device configurator software. Many other wireless sensor network technologies do not support central configuration changes this way.
Pulse and Totalizer (Turbine Flow)
Most plants still rely on periodic field operator rounds reading registers/counters on turbine flow meters and other meters manually recording data in a paper form on a clipboard or in a mobile digital device like a tablet. Due to infrequent rounds, for example daily, weekly, or monthly data collection, energy management practices like indexing energy and utilities consumption against production rate as well as energy and mass balances to detect inefficiencies or leaks is not possible.
The solution is instrumentation: pulse/frequency transmitters. What used to be periodic and manual, is now real-time and automatic.
Pulse/frequency conversion and totalization is used in conjunction with turbine flow meters and other meters for monitoring consumption of water and other utilities for ISO50001 energy management such as energy cost accounting, leak detection, and overconsumption detection to improve sustainability.
Beyond reducing data collection cost and keeping people out of harm’s way, real-time pulse/frequency data transmission thus helps avoid energy overconsumption and losses.
Data transmission can be interrupted for short or long periods of time. Therefore it is recommended to use pulse/frequency transmitters with built-in totalizer so the total volume (or mass, energy, or other amount or just pulse count) is still tallied locally. That is, the pulse/frequency transmitter provides both flow rate and total.
[Repeat] Wireless sensor network technologies are not all the same. There are significant differences in capabilities between various technologies. Therefore select wireless sensor network technology carefully. Turbine flowmeters and other utility meters are often used in use-cases where the flow shall be displayed in an HMI, dashboards, or be used in some form of analytics or energy management information system (EMIS) software, even displayed in the historian or DCS in some plant philosophies. Many wireless sensor network technologies do not define a standard data format meaning coding/scripting specific to each type of sensor is required to integrate the data into third-party systems. When the sensor is replaced this coding/scripting must again be redone. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART defines a standard data format so sensors for DP, level, and flow etc. work the same way. This enables a WirelessHART gateway to automatically convert data into OPC-UA, HART-IP, and Modbus/TCP protocols etc. to bring data into third-party software by simply selecting desired data points, without the need for coding/scripting. This also makes future device replacement easier. The recommendation is to deploy wireless sensor network infrastructure based on the WirelessHART standard IEC62591. Measured values are transmitted with status and engineering unit.
A wireless pulse/frequency transmitter optionally comes with an LCD indicator for local display useful when working in the field.
Many turbine flow meters have built-in pulse output while other mechanical flowmeters must be fitted with a snap-on reed switch to get the pulse output. The same is also true for other kinds of devices with pulse output. That is, pulse/frequency transmitter works with existing flow meters and other devices with pulse output, so no need to replace these devices.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and turbine flow meters based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
[Repeat] Returning to a transmitter in the field to verify the configuration is correct, has not been tampered with, or to make changes would be time consuming. The recommendation is therefore to use wireless sensors using the WirelessHART protocol as this allows over-the-air configuration (parameterization) such as flow unit, volume unit, and K-factor to be checked and changed from a central location from Intelligent Device Management (IDM) software or a simple device configurator software. Many other wireless sensor network technologies do not support central configuration changes this way.
Level Switch
Most plants still rely on periodic field operator rounds checking through sight glasses or through the side of tote tanks etc. to make sure level is not too low and not too high. With the large number of sight glasses in a plant, personnel are unable to go check frequently. Due to infrequent checks, for example weekly, monthly, or yearly, low or high condition goes unnoticed. Depending on the use-case for the sight glass, not capturing this condition can result in all sorts of problems such as running out of (liquid) consumables, equipment damage, overfill, and other risks. In some cases field operators standby at the tank or pond with a walkie-talkie during filling operations which is not productive. Another challenge is that there are tanks around the plant that have a level sensor, but only one. If that single sensor has failed ‘on scale’ all sorts of problems such as overfill could occur. To make sure that single sensor is working as it should, many plants still rely on periodic field operator checks through a hatch to visually confirm the level. Climbing tanks for inspection is time consuming.
The solution is instrumentation: level switches. What used to be periodic and manual, is now real-time and automatic.
Level switches are used for monitoring of consumables levels to make sure they are not too low or too high, that equipment lube oil and coolant levels are not too low, waste and sump level not too high, and many others, often not directly related to the control of the process but important to the availability of the production. Use-cases include storage, buffer, and tote tanks. Waste tanks and sumps. Remote ponds, reservoirs, and bunds/dikes/dykes. Other use-cases include tank overfill prevention, tank top water pooling, and tank floating roof tilt detection.
Another approach is to instead measure the level with a transmitter as explained above at Guided Wave Radar Level and Differential Pressure, and set an alarm in software.
Beyond reducing data collection cost and keeping people out of harm’s way, real-time level switches thus help prevent overfill, spills and fire, avoid equipment failure, production downtime and associated opportunity cost, as well as repair cost.
A vibrating fork level switch can distinguish between liquids with different density such as telling a petroleum product from water. The recommendation is therefore to use a vibrating fork level switch that can communicates the fork frequency to the automation software.
[Repeat] Wireless sensor network technologies are not all the same. There are significant differences in capabilities between various technologies. Therefore select wireless sensor network technology carefully. Level switches are often used in use-cases where the level status and fork frequency shall be flagged in an HMI, dashboards, or even flagged in the historian or DCS in some plant philosophies. Many wireless sensor network technologies do not define a standard data format meaning coding/scripting specific to each type of sensor is required to integrate the data into third-party systems. When the sensor is replaced this coding/scripting must again be redone. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART defines a standard data format so sensors for pressure, temperature, level, and flow etc. work the same way. This enables a WirelessHART gateway to automatically convert data into OPC-UA, HART-IP, and Modbus/TCP protocols etc. to bring data into third-party software by simply selecting desired data points, without the need for coding/scripting. This also makes future device replacement easier. The recommendation is to deploy wireless sensor network infrastructure based on the WirelessHART standard IEC62591. Measured values are transmitted with status and engineering unit.
A wireless level switch optionally comes with an LCD indicator for local display useful when working in the field.
Some level switch models can optionally be set with fast update period of only a second to capture rapid changes.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and level sensors based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
[Repeat] Instrument technicians are very familiar with the standard HART field communicator also used for your 4-20 mA/HART devices. The recommendation is therefore to use wireless level switches with a HART communication maintenance/console port (grabber hook terminals) to enable calibration locally while you verify the level.
[Repeat] Returning to a sensor in the field to verify the configuration is correct, has not been tampered with, or to make changes would be time consuming. The recommendation is therefore to use wireless sensors using the WirelessHART protocol as this allows over-the-air configuration (parameterization), such as delay to be checked and changed from a central location from Intelligent Device Management (IDM) software or a simple device configurator software. Many other wireless sensor network technologies do not support central configuration changes this way.
Gas Concentration
Most plants still rely on wearable gas detectors for toxic gases like hydrogen sulfide (H2S) and carbon monoxide (CO), and for oxygen (O2) depletion. The problem with using this approach exclusively is that the person is only made aware of the gas after they have walked into the area where the gas is present. And the person must have the sensor with them, which may not be the case if the gas is coming towards an unsuspecting person. Lastly, others are not notified. The same is true for oxygen depletion. A wearable gas detector is good as a second line of defense. Detecting high concentration of toxic gas or oxygen depletion can be immediately dangerous to life or health (IDLH) such as poisoning or asphyxiation.
The solution is instrumentation: permanently installed gas concentration sensors. What used to be after entry, is now before entry.
Gas concentration is used for monitoring wide areas using multiple sensors to detect dangerously high concentration of for instance HS2 or CO, or low concentration of oxygen (including when there is a risk of other gases like nitrogen, argon, or helium displacing oxygen). This tells personnel to not enter, to evacuate, if need be, and take corrective action. This is not directly related to the control of the process but important for the safety of the plant.
Permanently installed gas concentration sensors thus help keep people out of harm’s way. It is a good complement to wearable gas detectors.
[Repeat] Wireless sensor network technologies are not all the same. There are significant differences in capabilities between various technologies. Therefore select wireless sensor network technology carefully. Gas concentration sensors are often used in use-cases where the gas concentration shall be displayed and alarmed in an HMI, dashboards, even displayed and alarmed in the historian or DCS in some plant philosophies. Many wireless sensor network technologies do not define a standard data format meaning coding/scripting specific to each type of sensor is required to integrate the data into third-party systems. When the sensor is replaced this coding/scripting must again be redone. Such wireless sensor network technologies are not suitable for plants. However, WirelessHART defines a standard data format so sensors for pressure, temperature, level, and flow etc. work the same way. This enables a WirelessHART gateway to automatically convert data into OPC-UA, HART-IP, and Modbus/TCP protocols etc. to bring data into third-party software by simply selecting desired data points, without the need for coding/scripting. This also makes future device replacement easier. The recommendation is to deploy wireless sensor network infrastructure based on the WirelessHART standard IEC62591. Measured values are transmitted with status and engineering unit.
A wireless temperature sensor optionally comes with an LCD indicator for local display useful when working in the field.
Some gas concentration sensor models can optionally be set with fast update period of one second to capture sudden changes.
Gas concentration sensors have limited lifespan. A sensor must be placed once they have reached the end of its service life. The recommendation is therefore to use gas concentration transmitters where the sensor module can be replaced in the field without the need for tools.
[Repeat] Having infrastructure for multiple wireless sensor network technologies would be an undue burden on the I&C team. The recommendation is therefore to deploy wireless sensor network infrastructure and gas concentration sensors based on the WirelessHART standard IEC62591 just like other wireless sensors for a uniform implementation.
Action Plan: Transformation by HyperAutomation
Without additional sensors there is no reliable condition analytics, performance analytics, no integrity analytics, no risk analytics, no process analytics, and no emissions analytics. You can’t get real-time dashboards from historical data. You can’t predict using historical data.
Industry 4.0, digital transformation, and the Industrial Internet of Things (IIoT) is all about industrial automation. This includes automation of manual tasks such as data collection. Here’s an action plan for which you can allocate a person responsible, date of completion, budget, and other resources:
Share this essay with your reliability, maintenance, integrity, sustainability, energy, safety, production, and quality managers now. Digital transformation (Industrie 4.0) means a new era in automation so make sure to invite your I&C team. And remember, always ask for product data sheet to make sure the software is proven and pay close attention to software screen captures in it to see if it does what is promised without expensive customization. Well, that’s my personal opinion. If you are interested in digital transformation in the process industries click “Follow” by my photo to not miss future updates. Click “Like” if you found this useful to you and to make sure you keep receiving updates in your feed and “Share” it with others if you think it would be useful to them. Save the link in case you need to refer in the future.
with sharing and discusion to elavate the knowledge
2 年Dear Jonas Berge to optimize result of analytic how data needed (tag-point) for thermal unit and it's same amount if at others (hydro,gas and geithermal).Tks