In my project, PLC(VPB40) plays role as server, it opens the port and listen to connection request from IPC.
Normally, both sides are working well. However, there is QCD error if production line stops due to part missing.
It means that connection between IPC and PLC is established, command from IPC to PLC is correct and response from PLC to IPC is also correct. In this case, if production line stops becase part missing and connection between IPC and PLC kept. After a period of time, customer told me around of 2-3 hours, there will pop up QCD error on PLC HMI.
Since i am not so clear about QCD mechanism. Anyone could help explain it and give me some advice about this error.
