text: <s>[INST] How to check an AENTR Analog output module faulty or not. It's not generally voltage 0-10V  when forcing a value eg: 25000 from PLC. Only 0V. When I replaced this AO with another one, the new one worked and generated 7.7V. AENTR is fully green LED on. PLC device config. no error. How to diagnosis an AENTR Aanalog output module faulty or not? [/INST] I would start by going online with the controller and looking at the module in the IO tree.  if there is something wrong, the icon for module will indicate a fault and you can open that module properties to get more details. All the module status that you see in Logix Designer, can be gathered programmatically via GSV and/or MSG instruction  and then displayed for an operator on the HMI e.g. EntryStatus, FaultStatus, etc. Assuming the hardware is fine, then I'd look at the logic.  Specifically, I'd eliminate the logic and just command the outputs directly by their IO-defined tag.  This is what I call an IO check-out where I check every channel on every module.  I would have the AO wired to my multimeter where commanding the IO-defined tag would drive the AO and I could verify the value at the AO terminals via my multimeter.  You can bypass the AO logic by doing an online test edit where you eliminate the logic that is writing to the AO channel.  You can test the delete and then untest delete, thus cancelling the delete.\n </s>