S5- 115U CPU-943B in Stop Mode With Error LED QVC and BASP

[vicyubal]

I have S5 System which CPU is 115U CPU-943B,
It is running for several years but suddenly it stops with ERROR LEDS light on STOP, QVC and BASP.
With this problem, I resetted it completly by unpowering the CPU, removing the back-up batteries & EPROM for 10 mins and power it again.
BY powering it again, I reset the CPU by holding the switch to "OR" mode and clicking the "RUN/STOP" key switch 3-4 times.
The error was gone and I inserted again the EPROM and dowloaded the backup PLC program but it backs again to "STOP" mode with the same error.
So, How can I put back this CPU to running condition.

Thanks,

Vic

[kriztof]

QVZ is triggered when CPU can't access I/O module (this error occurs if a module fails to acknowledge within 160 µs of being
accessed). I suggest you to create empty OB23 and upload to CPU. If CPU will run then you should replace faulty card. For detailed diagnostic you should check also ISTACK.

[dekor]

Dear friend,
from my experience,
1. I suggest you to check if the cards are powered by power supply.
2. I meet several times poor connection on rack.

Good luck.
dekor

[Serge_n]

... BY powering it again, I reset the CPU by holding the switch to "OR" mode and clicking the "RUN/STOP" key switch 3-4 times. ...

Do the same with the inserted module EPROM.

[hasnan86]

Good day everyone, i had faced the same problem like vicyubal with my S5 CPU-115U 493B plc. I had try the recommended which had given in this topic and i replaced with the new CPU but i still get the same problem occur. What can i traced that 2 of function block (FB) had made the QVZ LED appear. Before this, I had upload the block stage by stage (e.g OB,PB,DB & FB) into the CPU.

1) Upload all OB-->No QVZ fault-->start PLC=OK
2) Upload all PB-->No QVZ fault-->start PLC=OK
3) Upload all DB-->No QVZ fault--> start PLC=OK
4) Upload all FB-->2 of all FB had made the QVZ LED appeared while uploading even tough the 2 FB had programmed inside it -->start PLC=ISTACK
5) Check backup battery=OK,Tried change new battery and re-upload program from stage 1 until 4=still have QVZ fault.
6) Compared between programming inside the CPU with the source (PC)= No error comparison.

My questions are how to analyze the ISTACK and could it be the FB problem caused the QVZ fault and how the FB can caused QVZ?

[Serge_n]

4) Upload all FB-->2 of all FB had made the QVZ LED appeared while uploading even tough the 2 FB had programmed inside it -->start PLC=ISTACK

Which numbers FB?

[dekor]

Hi
have you check condition : missing caled DB?
Try to have a look at program structure.
dekor.