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EHELP: Converting Three Analog Signals to HART Protocol

EHELP: Converting Three Analog Signals to HART Protocol

Q: You have a product called HART Interface Module that will pull the 2nd, 3rd and 4th HART variables from a smart HART transmitter and create one 4-20mA signal for each. Do you have or know of an instrument that will take three 4-20mA signals into it and place themdin on one 4-20mA signal as the 2nd, 3rd and 4th variable? I would like to read three transmitters on one 4-20mA signal by reading the variables on my DCS System.

A: We have three products that can take multiple analog inputs and provide that signal data in the form of HART protocol. Those products are the TCM and THZ3/TDZ3, which are temperature input devices that can take a 4-20mA input across a resistor (shunt) as a mV input.  

The TCM is a 16-channel temperature input module that can be polled by a HART master using a device-specific HART command. This HART command retrieves all 16 channels of PV data in one HART message packet.

The THZ3 Dual Input Smart HART DIN-Rail or Field Mount Temperature transmitter can accept two (but not three) 4-20mA signals and write them to two of the HART dynamic variables riding on the analog 4-20mA output signal.

The TDZ3 has the same functionality as the THZ3 but includes a display and can be field mounted in hazardous or non-hazardous areas or mounted on DIN-Rail.

Information on each of these instruments can be found in the Interface Solution Download Center.

Published: January 26, 2016
Categories: E-Help
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