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Open Circuit Detection for a 4-20mA Input

Problem: I need a low pressure alarm on my instrument air system, but I can’t afford to have a system shutdown if the pressure transmitter fails and the header pressure is still acceptable. I also want to use the signal for monitoring in the Control Room.

Open Circuit Detection for 4 20mA Input Problem Solvers Moore Industries
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Solution: A SPA2 Programmable Alarm with a dual relay and analog output will do the job. Set Relay 1 with a time delay to close when the header pressure falls below an acceptable level and Relay 2 to open if the pressure transmitter fails so a shutdown will not occur.

Model Number Example
SPA2 / HLPRG / 2PRG / U / -AO [DIN]