Using Communication Protocols like HART® to Enhance on-site Gas Detection

Communication is key in all areas of life; in fact, our ability to communicate in such complex ways with each other is arguably one of our most defining features as a species. With this in mind, it’s no surprise that the application of communication capabilities to smart field devices and process monitoring technologies is able to bring valuable dimensions to industry.

Safety control systems are usually organised with a hierarchical system of three core levels of hardware and software. The highest level is represented by the Human Machine Interface (HMI), which is often a PC based solution. This allows an operator to interact and monitor the system, using protected passwords allowing for acknowledgement and or modification as needed. The second level down is the Programmable Logic Controllers (PLCs). These allow signals from analogue, digital and bus to interface with the HMI. The tertiary level consists of the devices such as Infrared (IR) gas detectors, toxic sensors, pressure and temperature sensors and flow measurement field devices.

The type of communication protocol employed by the system to interface between the PLCs and field devices will determine the type of data that can be obtained from a device and the frequency with which that data can be transmitted or received. Many PLCs tend to use a 4-20mA input.