resetting program on CQM1 CPU43

[-M!ll- 0]

i mistakenly program my PLC with TXD command without limitting the instruction usage, n now, my PLC just keep sending data from the serial port.. any other way to overcome this situation so i can re-program my PLC ? thx

[Nibroc 4]

Hi, Try turning ON DIP Switch 5 on the CPU, you should then be able to connect to either the RS232 or peripheral ports using CX-Programmer.

[-M!ll- 0]

its already ON, n i don't have the cable for peripheral port.. thx for the advice :) any other way? do u guys think replacing the battery n put it back could erase the program memory? Edited 20 Dec 2005 by -M!ll-

[PdL 71]

Perhaps someone has an idea to generate an error so that it switches to stop/program mode without causing harm !? I'm not sure the ways I can think of are safe so I won't suggest them. You could remove the CPU battery and wait for the program to clear.

[-M!ll- 0]

will it be okay if i remove the battery n for how long? will it effect anything else in the PLC unit?

[benbrad 0]

Being a bit of a layman, I think I'd remove an IO module or if none fitted, I'd fit one. This will cause an error that will halt the program running, then you should be able to communicate with it. Don't know for certain that this will work but it's got to be worth a try. Ben

[-M!ll- 0]

u mean when the program is running? i don't think it safe? or does it?

[benbrad 0]

Turn off PLC Remove module Turn it on again Never remove anything when turned on

[Nibroc 4]

... Not sure a CQM will fault with a missing module? Try removing the end plate ? Nibroc

[PdL 71]

My thought exactly.

[-M!ll- 0]

i already try turning off the PLC, disamble all the module for a while n put them back together n still don't work.. what end plate? the one after the output module? which one?

[Nibroc 4]

Yes, the 'cover' plate on the far right of the PLC, power off, remove plate and power on again, the PLC should fault. Nibroc

[-M!ll- 0]

it did fault when i remove the module n turn on the plc, but i still can't access the PLC from cx-programmer.. n when i put the end plate back, it remains the same with the previous situation.. thx for the advice anyway..

[Nibroc 4]

I suspect the RS232 port is in 'RS232' mode which allows the TXD instruction to operate, however will not allow CX-Programmer to communicate. You may need to aquire a cable/adaptor to allow you to access the PLC via the peripheral port, this would make life much easier for you to continue your project as it will allow you to monitor the PLC via the peripheral port whilst your serial application uses the RS232 port? As PDL mentioned, removing the battery will cause program/data loss in the PLC, which also may reset the port. I have never tried this and would use this only as a last resort!! Not sure how long it would take, the book says you should change a battery within 1 minute, so longer than 1 minute. Nibroc Edited 20 Dec 2005 by Nibroc

[-M!ll- 0]

so, do u think its okay if i remove the battery, since i'm not sure how to reset the program memory... maybe i'll stick in this forum for a while, maybe some other members have other advice for my situation.. thx edit: ah.. i got it.. i can connect n reprogram the PLC when i take off the end plate... thx a lot guys.. u've been very helpful Edited 20 Dec 2005 by -M!ll-

[PdL 71]

So what was it in the end !?

[-M!ll- 0]

i reprogram the PLC when the PLC suspect the error after i remove the end plate, n i can communicate thru the RS232 port to the PLC n reprogramed.. thx to nibroc :) now i limit the TXD instruction using start n stop switch... :) Edited 20 Dec 2005 by -M!ll-

[PdL 71]

Ah ok you said you tried that already and it didn't work so I thought you found another way. Indeed in this case it's useful to be able to disable the TXD instruction. But as said, it is recommended to get a peripheral cable/unit so you can also monitor your program when running the comms.

[-M!ll- 0]

i don't think we got it when we purchase this unit, n i'm not sure i can find it in my town...

[PdL 71]

They DO deliver mail in your town ? CQM1 CIF02 on Ebay (USB version alternatively)

[-M!ll- 0]

i'll talk about that to my supervisor.. cause right now i just want to finish my program n graduate... wish me luck :) cause i need it XD

[-M!ll- 0]

finally... i finished my final project presentation, it was like hell.. but i managed ^^ PLC is sure a new thing in my faculty.. lots of questions regarding PLC than questions about HMI program that I made T___T thx to u guys.. all your inputs help me alot ^___^ best regards -M!ll-