More than 30 million Hart-enabled instruments are installed in process plants worldwide, and most process transmitters made today are Hart compatible. So says the Hart Communications Foundation, which notes that the cost of installing a plant-wide Hart monitoring system and the lack of familiarity with alternatives means that Hart data frequently goes unused.
A white paper from Moore Industries, North Hills, Calif., shows why this does not have to be the case. “Extracting HART Data from Smart Instruments” describes how the use of a Hart interface module such as the company’s HIM can serve as an effective method for gathering Hart information. Once gathered, the data can be used for monitoring instrument status, diagnostic data, alarms, calibration values and alert messages.
Hart interface modules can be installed across any termination point on a 4 to 20 mA process loop without interfering with the analog signal to the control system. It can be configured to extract or read the Hart variables from the field transmitter. It strips out these process variables from the Hart digital signal, converts them to 4 to 20mA and discrete signals, and sends that data to the process control system or other receiving devices. Process variables that are commonly transmitted by Hart interface modules from multivariable transmitters include mass flow, temperature, pressure, differential pressure, density or volumetric flow.
Engineers can use Hart interface modules to monitor critical transmitters and applications. For example, a Hart alarm can be set to monitor diagnostic data from a critical process transmitter when it is reconfigured or when a field device malfunction occurs. Hart interface modules can also be used for valve monitoring, emergency shutdown valve testing, monitoring multi-dropped instruments, and even converting Hart data to Modbus RTU protocol.
“Extracting HART Data from Smart Instruments” can be found at the “White Papers and Articles” section of the Moore Industries website here.