V200-18-E6B Inputs not working

[sgull]

Hi All

I have several V280 with a snap in V200-16-E6B.

On one of the systems all digital inputs have stopped working.

I swap the faulty unit with another and everything works, so I know the various 24vdc supplies are ok.

The unit appears to be fitting correctly on the PLC.

Does anyone know if there are any internal fuses on the snap in to protect the inputs?

Regards

Denis

 

[kratmel]

1 hour ago, sgull said:

Does anyone know if there are any internal fuses on the snap in to protect the inputs?

No. No fuses installed in input cirquitry. But two fuses installed for analog output and HS output - you can find it.

In Snap-in installed  PS2705 or similar optocoupler for all inputs. You can test faulty unit inputs for both separated channel input group I0-I8 and I9-I17

Use multimeter in diode checking mode - all standard input to COM wire must show 1500-1800 readout - the same for both direction. HS inputs has lower readout then reular inputs.

If tested ok - module internal cirquit (parallel-to-serial convertor) damaged.  Please check internal circuit for corrosion. 

[sgull]

Thanks Kratmel

I found the two fuses for analog in and HS out.

On the inputs with diode selected on the meter for I0 to I3 i get 1.056

for all other inputs i get 1.330.

The board looks very clean with no signs of corrosion.

Regards

Denis

 

[kratmel]

1 hour ago, sgull said:

On the inputs with diode selected on the meter for I0 to I3 i get 1.056

for all other inputs i get 1.330.

It looks like no damage on inputs before galvanic isolation.

In my lab only connector Snap-in to PLC make problems some times.

You can try to install faulty Snap-in to anothe PLC for test.

Having some experience in using an oscilloscope and reading the manuals for the applied microcircuits, you can determine how the parallel-to-serial converter works and understand at what stage the circuit stopped working.

However, this is probably meaningless - it is easier to replace the module with a new one, since they are in production.

P.S. It would be interesting to play with a module broken in this way, but I have not come across modules with such a problem. I have already studied the operation of analog outputs, which had to be repaired after 220VAC voltage was applied there. I can say that galvanic isolation saved the PLC and I managed to get everything back to working order.

 

[sgull]

Thanks again for your time.

Going any further into the circuitry is beyond my capability.

The unit shows the same problem on other PLC's.

I have ordered a replacement.

Regards

Denis