Dziadek

cqm1h Error on connecting to plc

3 posts in this topic

Hello,

First thing, I'm new over here, so probably I don't know everything, and second thing, sorry if my English is worse than I think :(

Now, what's the problem: I have CQM1H - CPU51 plc, and until yesterday it worked fine. But when I tried to look into its communication protocols via cx-protocol, something went wrong as I suppose. Since that, I'm unable to connect to plc - usually message is "Failed to connect, check following:..." or sometimes "No response from plc" (which probably means that there is connection if pc can send data to plc?). LED "comm" on plc is not blinking when I'm trying to connect, so it looks... not good for me. I tried using rs232 port in cpu unit, on serial communications board, only peripheral left, because I don't have matching cable. Anybody knows how to make communication work again?

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We're you able to connect to the PLC before? Omron RS232 serial connectors have a different pinout layout compared to the usual PC Standard RS232.
You need to make sure you wired it up properly. There's already lot's of wiring reference in this site that you can search about it.

Also, why are you trying to look into it with CX-Protocol? Is the Serial Comm. Board connected to a certain device with custom protocol?
You need to turn DIP Switch Number 8 on the CPU Unit prior to powering it up if you want to connect to the Serial Comm Board via CX-Protocol.

For the CPU built-in RS232 Port, try turning DIP Switch Number 5 prior to powering up, so that the RS232 Port will be using it's default communication settings. This will make Auto-Online connection using CX-Programmer easier.

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Before that everything worked fine, I could upload or download program, set plc state to run, program, etc. Cable that worked wit it I bought with cpu unit. Today I tried with one that I prepared basing on "operational manual", still nothing.

With protocol.. it was because I wanted to check something, I don't remember even what it had to be.

Pin 8 was on during tries with protocol, now it's off. With 5 I have to try, maybe it will work.

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