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Hi guys
Hope everyone doing OK

I am an electric technician for the food industry and I come across Yesterday to an Unifiller machine with Unitronics PLC and V200-18-E4XB.

The output of the I/O card control few pneumatic solenoid.

One particular solenoid is not working anymore. I check the power supply, the integrity of the wire and the status of the solenoid and all are working 100%
The positive of the solenoid is wire direct on the OUT 13 of the V200-18-E4XB.
When running the program on the PLC I can't see any voltage output from the channel 13.

I ask the operator to create a new receipt in case the original one was bugged.

I open the I/O card and I see that all the output are managed by mosfet, so very reliable! Is very had for me to believe the channel 13 is faulty.....

Any suggestion, test, or.... YES buy a new board! 🙂


Much appreciate

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  • MVP 2023

Unfortunately, I don't have such a module on my desk, so if possible, post a photo of its board from both sides.

My recommendations:

1) check whether the valve coil is not shorted. It is worth doing this by comparing the resistance with neighboring similar ones in a cold state. If the coil had a short circuit - the transistor in the module is 100% destroyed.

2) If the check according to point 1 is successful. Check the operation of the coil by applying voltage directly to it. It is good if you can compare (measure) the current of the suspected coil with the current of the working one.

3) If the check according to points 1 and 2 is successful. Reassemble the circuit as it was and try to see if the signal is coming to the desired output using the PLC Information Mode.

4) If the signal comes and you see the change of state of the desired output in the Information Mode, and the valve does not work, check the power supply at the input V1 provides the power supply for Outputs #9, 10, 11, 12, 13, 14, 15, and 16.

5) if the steps listed above have been carried out and there is no success - repair the unit or replace it with a new one.


Regarding the repair - if there are photos - I will try to provide recommendations.

The main thing in your situation is to perform points 1 and 2. This will protect the new or repaired module from repeated destruction.

Consider Ausman's question. Diodes are important for solid-state outputs to coils.

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