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[ATR121-AD] wrong temp display

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AndreK
Posts: 4
Joined: 27/08/2020, 9:33

[ATR121-AD] wrong temp display

Post by AndreK »

Hi, I have a problem with 2 new ATR121-AD v7.07. I use them with thermocouples type J. Configuration is done correctly. Istead of 35°C they display 180°C. An older ATR121-AD with v3.05 shows the correct temperature with the same configuration and the same thermocouple.

What can I do? Factory reset and config again did not help.
Pixsys tecnico 6
Moderatore
Posts: 1184
Joined: 12/09/2016, 14:49

Re: [ATR121-AD] wrong temp display

Post by Pixsys tecnico 6 »

Hi,
could you please post a wiring diagram of how you connected thermocouple J to the ATR121? Have the wires of the thermocouple been extended? If so, what type of cable are you using? Is thermocouple J electrically isolated or not?

Best regards.
AndreK
Posts: 4
Joined: 27/08/2020, 9:33

Re: [ATR121-AD] wrong temp display

Post by AndreK »

Thanks for Your answer. Thermocouple is electrically isolated. The wires are extended by a type J cable. Polarity is correct: + to 12, - to 11. An older ATR121 instead of the new one in the existing wiring works correctly.
Pixsys tecnico 6
Moderatore
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Joined: 12/09/2016, 14:49

Re: [ATR121-AD] wrong temp display

Post by Pixsys tecnico 6 »

Of course the connections are correct, but is PIN 11 of the ATR122 (the -) connected only to the probe or to the entire device ground? What type of power supply are you using for the ATR121?

Best Regards.
AndreK
Posts: 4
Joined: 27/08/2020, 9:33

Re: [ATR121-AD] wrong temp display

Post by AndreK »

There is no ground connection to pin 11. Power supply is 24VAC. The older ATR121 works correctly in the same enviroment.
Pixsys tecnico 6
Moderatore
Posts: 1184
Joined: 12/09/2016, 14:49

Re: [ATR121-AD] wrong temp display

Post by Pixsys tecnico 6 »

If using 24Vac, the 0Vac terminal of the power supply must not be connected to ground. How did you connect the 0Vac of your power supply? Can you post a scheme of the electrical wire connections?

Best regards.
AndreK
Posts: 4
Joined: 27/08/2020, 9:33

Re: [ATR121-AD] wrong temp display

Post by AndreK »

Now the ATR121 works. The only solution has been to install an additional power supply with 24VDC for the atr121.
This problem is a little bit annoying for maintenance if there is to replace old with new in an existing machine.
Pixsys tecnico 6
Moderatore
Posts: 1184
Joined: 12/09/2016, 14:49

Re: [ATR121-AD] wrong temp display

Post by Pixsys tecnico 6 »

Good morning,
thank you for the feedback you sent us. The solution you have adopted is correct because the new regulations have forced us to slightly modify the hardware for the analog input of the instrument. As a result, it is no longer possible to use the same system ground reference for the connection of a thermocouple, so it is necessary to slightly modify the system as you have done.

An alternative solution could be to disconnect the system ground (if you can disconnect it in your system). In this way, terminal 11 of the ATR121 controller (PIN - thermocouple) is not directly connected to the system ground and should work.

Best Regards.
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