This application was written for a requirement where a temperature and pressure indicator with alarm outputs for both measurements was needed. With adaptation it could be used for other applications with analogue output sensors.

Using 2x 4..20mA signals over 500 Ohm resistors we get 2-10V inputs scaled as -31 - 125C and -250 - 1000kPa. There are 2x Potentiometer inputs for alarm set points. The temperature and pressure inputs are displayed and compared to the 2 alarms, both with hysteresis of -2/+2. If an over temperature alarm is activated, relay output 1 is turned on. If an under pressure alarm is activated, relay output 2 is turned on.

Inputs:
I5 Temp. (2-10V)
I6 Temp Alarm Setpoint (pot)
I7 Pressure. (2-10V)
I8 Pressure Alarm Setpoint (pot)

Outputs:
O1 Over temperature (relay)
O2 Under pressure. (relay)

Model used:
SA12 R 24 VDC (Crouzet article no. 88950041)

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