V130 Serial Port Fail

[Flex727]

I have a V130 that I use occasionally for some programming work that I suddenly can't communicate with via serial comms. In INFO Mode I can see TX & RX occurring during handshaking, but VisiLogic gives me the dreaded Communications Error box. I've tried two different computers with the same result (one of which is Win 7 and the other Win 10). Both computers will communicate just fine with a V1210 using the exact same cables, so this appears to be a problem with the V130. INFO Mode shows that all the comm setting are correct in the V130, as follows:

COM 1 - RS232

Prtcl: PCOM

Settings: 115200, 8, n, 1, N

Ign Brk: N

Any suggestions on the best way to approach troubleshooting the problem?

[kratmel]

Is it possible that port is configured to RS485 (via jumpers)  and Visilogic can not see two RS232 line for send Brk command?

 

 

[Flex727]

No, I checked that. And anyway, I have been using this PLC for programming work for a couple of years with no problem and have never opened it up.

A second serial port is cheap, so I'm going to install one this afternoon and see if that works.

[kratmel]

So another idea. Is it possible that SB 314 (Block PC access to PLC. OFF by default. When ON: access via VisiLogic, RA, etc. blocked) is ON?

[Flex727]

55 minutes ago, kratmel said:

So another idea. Is it possible that SB 314 (Block PC access to PLC. OFF by default. When ON: access via VisiLogic, RA, etc. blocked) is ON?

Great suggestion! Unfortunately I was already in the process of installing the serial module when I saw your comment.

End result: Got the V100-17-RS4 module installed (very difficult by the way) and the PC connected right away using Port 2. Still doesn't work on Port 1. Everything else about the PLC seems normal and functional. And, of course, SB 314 is off.

[Ausman]

2 ideas to try Flex.

1).  Change the battery?  Even us humans sometimes don't work properly when we're a little tired.

2).  Do a full Init & Reset?

3).  Drop the baud rate progressively and make sure that you do the same in Device Manager.  On my 130s I always have them running at 9600, mainly because of this being the same speed I run the 485 modbus loops at and it prevents confusion.  Perhaps W10 has again  done something else to serial comms!

Yeah yeah, I know I said "2 ideas".  I did that initially and just left it there for the smarties to discover after I had another brainwave.

cheers, Aus

[kratmel]

It is strange.

For me, in this case, it is important to determine whether it is a hardware or software problem.

According to you - you saw in the buffer RX from PC and panel to PC TX.

Question: Did the answer reach from the panel to the computer? I think not, so the TX panel line is either dirty or damaged.

So the test is to measure the voltage of the logic "1" at the TX output of the RS232  PLC port.

There should be a level close to -10V relative to GND. If it is not there - then ADM202EA - failed.

 

 

[Flex727]

21 minutes ago, Ausman said:

1).  Change the battery?  Even us humans sometimes don't work properly when we're a little tired.

PLC had been sitting on a shelf for 6 months and the last program was still in it and working when I powered up (the previous program was not "burned").

22 minutes ago, Ausman said:

2).  Do a full Init & Reset?

No, probably should have tried this.

23 minutes ago, Ausman said:

3).  Drop the baud rate progressively and make sure that you do the same in Device Manager.  On my 130s I always have them running at 9600, mainly because of this being the same speed I run the 485 modbus loops at and it prevents confusion.  Perhaps W10 has again  done something else to serial comms!

Did try dropping the baud rate. Note above that I tried on two different computers - one was Win 10 and one was Win 7. Both were able to connect to other Vision PLCs using the same serial cable.

20 minutes ago, kratmel said:

For me, in this case, it is important to determine whether it is a hardware or software problem.

According to you - you saw in the buffer RX from PC and panel to PC TX.

Question: Did the answer reach from the panel to the computer? I think not, so the TX panel line is either dirty or damaged.

So the test is to measure the voltage of the logic "1" at the TX output of the RS232  PLC port.

There should be a level close to -10V relative to GND. If it is not there - then ADM202EA - failed.

Agreed. Isn't it amazing that a piece of electronics can sit on a shelf and fail without any activity whatsoever. I probably won't have time to troubleshoot further since I now have a working Port 2, but it would be nice to know what happened.

[kratmel]

You can write something like 1,2,3..... send to port on panel and do loop by connecting  TX to RX on panel (best idea -connect it on connector on PC end). Then try to see what happend in buffer.