Hello everyone. 

Few day ago I faced problem with AI 6ES7331-1KF01-0AB0. One of the 8 chanel's is used for tank level measurement( E+H 2 wire pressure sensor) . Bellow attached photo shows wire connection. when I disconnect wire from pin 12 ( I+) and only pin 15( M-) is connect to 24v power supply 0v at VAT table that PIW gets value between 7000-9000. I tested AI card with current tester ( but connection type was 4 wire ) and system measures correct value 4ma-0; 20ma-27648.

1. El. cabinet PE is good. 

2. Analog wires are shielded and grounded well.

3. between N ( neutral) and DC power supply 0v wire potential is 0.05v.

Any ideas how to fix this issue will be appreciated. 

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Split from Problem in Analog input card.

Hello Grixo

Hope you have connected all M- to each other to avoid potential voltage is less than 2 vdc.

I.e 5,10,..40 short 

Regards

Rudra

yes sure.Thanks for recommendation.

Problem finally solved. one AI showed overflow  ( short circuit on cable). after disconnection all inputs show correct vale. I am planing to deactivate all spare inputs  for security.