AC500 IO going off & on in logic but not physically
i have DI524 IO module with PM573-eth cpu, one of the DI is not going off & on physically on the card, but going off & on in logic (codesys Software). It is always on, if it goes off i have to count it as a fault. It is going off and on in logic for a second but not being able to see on the card Indication on that address. Thus it is counted as a fault in software. I tried & gave direct 24VDc on that DI & then it works fine i.e; no fault is generated. What can be the issue that in software it is showing high & low & physically no change. I have checked addressing & cross references everything is fine. Please help????
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Check if you happen to use Visualisation! Recently witnessed a similar problem - a DO will go on as required by the program, only to be turned off after a second! Stopping all software and forcing it on (F7) gave the same result! After a lot of hassle, the problem proved to be a visualisation - a BUTTON was configured with Input -> Toggle Variable checkbox -> the "strange" DO! So far so good! Then I decided to disable the manual operation for this DO - so I unchecked the Toggle Variable checkbox for the DO! The name of the DO was greyed out, making me believe it is out of the way - dream on! In reality, when the DO was turned ON by the program, Visualisation reacted as if the variable was toggled by hand, and accordingly toggled the DO state! Only after deleting the DO from the variable name textbox behaviour was back to normal!