What are the best practices for selecting and calibrating sensors for process control?

1 Define your objectives

Before you start looking for sensors, you need to define your objectives and requirements for your process control system. What are the key variables that you need to measure and control? What are the desired outcomes and performance indicators for your process? What are the constraints and trade-offs that you need to balance? How often do you need to update and adjust your control actions? By answering these questions, you can narrow down your options and prioritize your criteria for sensor selection.

2 Evaluate your options

Once you have defined your objectives, you need to evaluate your options and compare different types of sensors that can measure the same variable. For example, if you need to measure temperature, you can choose between thermocouples, resistance temperature detectors (RTDs), thermistors, or infrared sensors. Each type of sensor has its own advantages and disadvantages, such as cost, accuracy, response time, sensitivity, durability, and compatibility. You need to weigh these factors against your objectives and select the sensor that best suits your needs and budget.

3 Test your sensors

After you have selected your sensors, you need to test them before installing them in your process. Testing your sensors can help you verify their functionality, accuracy, and reliability, as well as identify any potential problems or defects. You can test your sensors by exposing them to different conditions and comparing their outputs with a reference or a standard. You can also test your sensors in a simulated or a pilot-scale process to evaluate their performance and suitability for your application.

6 Monitor and maintain your sensors

Finally, you need to monitor and maintain your sensors to ensure their continuous and reliable operation. Monitoring your sensors involves checking their outputs, status, and condition regularly, as well as detecting and diagnosing any anomalies or faults. You can use various tools and techniques for sensor monitoring, such as data analysis, visualization, alarm systems, fault detection and isolation (FDI), and fault-tolerant control (FTC). Maintaining your sensors involves cleaning, repairing, replacing, or recalibrating your sensors as needed, as well as keeping records and documentation of your sensor activities.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?