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Discussion Starter · #1 ·
here is the situation we have a selec pic 152 temperature controller that failed to work.

so I replaced with a selec PID 500 temperature controller both controllers have analogue output option.

however the second controller in the HMi via a plc shows a constant -80 degrees Celsius.

when I measure the analogue output I get 16mA which increases as temp increases.

when I get another pic 152 and connect. I get the correct reading in the HMI.

can this be a scaling problem in the program?

we are using Siemens S7 300


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Is your output 4-20ma or 0-10 volts?
 

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The fact that you had negative temp makes me wonder if the loop polarity was backwards on the 500 accidentally, and the PLC couldn't really scale beyond -80 degrees?
 

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Discussion Starter · #5 ·
The fact that you had negative temp makes me wonder if the loop polarity was backwards on the 500 accidentally, and the PLC couldn't really scale beyond -80 degrees?
there are like four other pic 152 in the same machine.when I disconect the analogue output cables I have -207 degrees celcius.

the thermocouples are type k.but this particular one still remains at -80degrees celcius

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Something's not hooked up right.

IF both controllers are 4-20 out, then both should work.

What terminal numbers did you use on the 500 controller for the 4-20 loop?
 

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Discussion Starter · #7 ·
Something's not hooked up right.

IF both controllers are 4-20 out, then both should work.

What terminal numbers did you use on the 500 controller for the 4-20 loop?
terminal 4 and 5.

while terminal 2and 3 I wired it to a solenoid valve that opens or closess the oil valve used for heating when the set point is reached

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