What's So Special About Industrial Internet of Things?

The Internet of Things (IoT) is all over the media with particular attention to the process and manufacturing industries for which the name Industrial Internet of Things (IIoT) is used. There are also IoT solutions for other application areas like transportation and healthcare etc. but you never hear about “TIoT” or “HIoT”. What makes industry so special it has to be singled out as IIoT? Here are my personal thoughts:

IoT is about digitally networking “things” such as sensors and actuators from the very first meter and then securely all the way across the Internet so all their data can be accessed from anywhere including the other side of the world. For the industry this means 4-20 mA and on-off signals are no longer sufficient, you need digital networking all the way from the sensors and actuators; bus or wireless. It is when it comes to this sensor & actuator level digital networking where the industry is very different from the other application areas. The home and office environment is not demanding and the applications are not critical so Ethernet, Wi-Fi, USB, and Bluetooth work fine. However, applications in plants boiling petrol (refinery), mixing volatile chemicals, and power generation (ensuring no blackout) are mission critical requiring real-time digital closed loop control. The outdoor applications on the process itself have challenges such as hazardous areas (explosive atmosphere), rain and sea spray, dust, hot desserts and bitter cold winters, direct sunlight, electrically noisy (switching and frequency control of heavy electrical loads), long distances with huge ground potential differences. There are other circumstances that make industrial applications challenging. For instance, the industrial sensors and actuators are handled by people with only big tools in their toolbox, and they must be able to replace these “things” without having to touch system software because their responsibility is instrumentation, so they are not allowed to work on the control system. The number of sensors in a plant outnumbers those in a home by several orders of magnitude.

Clearly more sensors and actuators is an industry trend as plants are becoming ever larger to get economy of scale, and the processes more complex to handle lower grade feed and meet increasingly stringent requirements for finished product. Plants are deploying more sensors for equipment condition monitoring to improve reliability and reduce maintenance cost, for performance monitoring and loss detection to improve energy efficiency, automate balance manual data collection for productivity, and to meet ever more demanding safety, health, and environmental (HS&E) regulations - a good thing.

By automating data collection like vibration, temperature, pressure, and fluid levels etc. the plant also enables remote access: from plant control room and maintenance office, from on-shore integrated operations (iOps) centre, from global engineering solutions centre, by equipment manufacturer, or third-party service provider. For instance, a very fast pressure transmitter with embedded statistical process monitoring (SPM) can detect pump cavitation to notify operators to check for closed valves, and maintenance to check for plugged strainer. If securely connected across the Internet, the corporate global solutions experts is able to compare the problem to other similar plants, the pump manufacturer for product issues, and a service provider to schedule overhaul.

Clearly Ethernet is ideal for higher level devices in the plant such as the controllers, variable speed drives and motor starters. However, Ethernet is not a good fit for sensors and actuators in a plant. It is extremely rare sensors come with Ethernet as an option. Those sensors are separately powered and include some flowmeters and panel mounted analyzers. However, most other sensors such as pressure, temperature, and level transmitters as well as control valves etc. are not available with Ethernet for several reasons. The concerns with using Ethernet in the field for instrumentation voiced by end-users include: Ethernet over copper cable is limited to 100 m while most plants are much larger. Ethernet switches and fiber optic converters in the field junction box would require power to be supplied. Integration is an issue as there are many industrial Ethernet application protocols such as Modbus/TCP, EtherNet/IP, and PROFINET incompatible with each other. Ethernet devices from different vendors using the same application protocol have different register assignment requiring system reconfiguration for device replacement. Ethernet wires are fragile and don’t use regular screw terminals, and fiber optics requires special skills. Ethernet switches have comparatively short MTBF. There are no standard entity parameters defined for Ethernet switches and devices making compatibility and interchangeability a challenge. Fiber optic components meeting the IEC 60079-28 hazardous area requirements for irradiance are rare. Ethernet grounding would require equipotential bonding throughout the plant. Industrially hardened intrinsically safe Ethernet switches are expensive. Industrial grade shielded Ethernet cable is expensive. Instrument technicians would have to be able to master IP address setting, subnet, gateway address for each device as well as cyber security products like firewalls and procedure for passwords, certificates, and firmware patching. Dependencies between the IT and I&C departments are created. An instrument technician would have to master IP address setting, subnet, gateway address for each device. Replacing devices in hazardous areas is cumbersome if the installation is not intrinsically safe, The handheld field communicators which all plants use does not support Ethernet instead requiring a larger laptop to be used in the field.

Similarly, Wi-Fi is the best choice for a great many applications but is not used in wireless sensors and actuators

Modern plants use digital communication from the very first meter, from sensors and actuators; FOUNDATION fieldbus and WirelessHART. Note that these are “H1” level fieldbuses (which should not be confused with H2 fieldbuses). Fieldbus instruments include pressure, temperature, level, and interface level transmitters, vortex flow meters, as well as field mounted pH, conductivity, and amperometric transmitters as well as control valve positioners, and intelligent on-off valves and many more. The key attributes of fieldbus include: two simple wires for bus power and communication, no power distribution to field junction boxes required, no data mapping for easy integration and replacement, simple and rugged screw terminals, no optical fiber splicing, passive junction boxes with no heat and long MTBF, standard intrinsic safety entity parameters for simple engineering and replacement, equipotential bonding not required, no IP address or IT department dependency, hot connection/disconnection in hazardous areas, long cables and spurs possible. Full interoperability of all device configuration and diagnostics is ensured by EDDL technology (www.eddl.org) and interchangeability for easy device replacement is ensured through universal parameters and device profiles.

Similarly, WirelessHART is ideal for battery powered sensors and actuators

It is interesting to note how fieldbus and WirelessHART complement Ethernet in the plant just like USB and Bluetooth complement Ethernet in the home and office.

Some would have you believe everything which is not Ethernet and TCP/IP is “proprietary” but I&C engineers know better. FOUNDATION fieldbus and WirelessHART are both IEC standards. There are several standard application protocols for Ethernet and TCP/IP too, but many of the application protocols are proprietary.

Some would also have you believe a device has to use IPv6 to be part of IoT but this is not correct. To be part of IoT all the device needs is a unique device identifier. Both FOUNDATION fieldbus and WirelessHART devices have this so each device can be uniquely identified in a world of millions or billions of sensors. A FOUNDATION fieldbus linking device or a WirelessHART gateway provides an IP address through which underlying sensors and actuators can be accessed across the Internet. 

There is ongoing work to breed a hybrid of Ethernet and Fieldbus - an "Etherbus" if you will:
https://automation2.com/2015/06/29/report-from-achema-2015/
(Scroll all the way down to “Ethernet at the Physical Layer for Field Devices Makes a Quiet Debut”)

Until then, Ethernet and fieldbus complement each other

 Well, that’s my personal opinion. If these ideas are useful to your work click “Follow” below my photo above.