With the HART Loop Converter (HLC) from Pepperl+Fuchs, you unleash the hidden advantages from your existing instrumentation. The only Ex approved HART Loop Converter on the market makes all the information from your HART transmitter and valve applications available. These devices could be:
Its versatility turns the HART Loop Converter into a universal solution if you plan on updating or retrofitting an operational plant.
For example, HART protocol-based multivariable mass flow transmitters sense three process variables (pressure, temperature, and differential pressure). Using these variables, they perform an internal calculation to derive mass flow. The mass flow information is transmitted as a standard 4…20 mA signal to the control system. Unfortunately, unless you have a HART-based control system, there is no way to continuously monitor the additional non-primary variables that are used to make the calculation.
Still, monitoring these variables may be desirable if one or more of the variables is especially important to the quality or safety of the process. In such a scenario, the HART Loop Converter extracts useful information from the multivariable transmitters that was previously not available.
Installed transparently across the 4…20 mA instrument loop, the HART Loop Converter reads the HART digital data that is continuously being transmitted on the smart transmitter’s analog loop wires, and converts it to standard 4…20 mA signals that can be readily accepted by a Distributed Control System (DCS) or Programmable Logic Controller (PLC).
This allows you to continuously track a multi variable transmitter’s second, third, and fourth variables. Each HART Loop Converter’s analog channel may be individually programmed to monitor the variables of your choice.
The HART Loop Converter can be ordered with additional 2 or 4 relay outputs. These can be used just like a traditional alarm trip to warn of high and/or low process conditions based on user-set trip points. The difference between the HART Loop Converter and a traditional alarm trip is that the HART Loop Converter responds to HART’s digital information, rather than to a loop’s analog signal.
This allows the HART Loop Converter to be set to monitor any available dynamic HART variable. For example, for a multivariable mass flow transmitter, a relay can be set to trip when the transmitter’s fourth variable (temperature) exceeds a user-set trip point. Each trip can be individually assigned. Both alarms can be assigned to monitor one process variable, or each can be set to respond to different process variables.