FX1N comm problem

[raveon 0]

I have a FX-1N that appears to working normally. After 3 processor changes and the Matsushita GT-11 has be repalced with new as well, still no go. The error is displayed in the GT-11 as ERFF. All cables have been replaced. ERFF fault says its a PLC issue. We are stuck - all 3 shifts. We need help. Thanks Edited 27 Mar 2012 by raveon

[kaare_t 155]

If you connect the computer directly to the PLC and use debug, what error code(s) can you read out? Does this occur if you disconnect the OP and reset the PLC?

[raveon 0]

The only error we get is at step 2065. Invalid operation error. We are dividing one D register by another D whose value is 0. It makes no difference if the OP is hooked up or not

[kaare_t 155]

You are getting error because of the DIV by 0. Check if the value is > 0 before doing dividing.

[Crossbow 295]

You should always code a compare in front of a divide to ensure the divisor is not zero. Common sense code elimintates a lot of PLC errors.

[Sergei Troizky 26]

The ERFF (no communication) error on GT11 display has nothing with the PLC program execution*. The display should communicate even with stopped PLC. Verify the display communication settings to match the ones of the PLC. Verify the communication cable. If all these is OK, the PLC port is out of order (if this is the integrated mini-din port). One of our customers had exactly this recently. *If the display is connected to an optional RS232 communication board port, the latter may become inaccessible for PC or HMI when subject to RS instruction execution. Which port is the display connected to? Edited 4 Apr 2012 by Sergei Troizky

[raveon 0]

Sergey Thank-you very much. The first display was fried. The second display got fried because of a loose wire on a reset PB. It had absolutely nothing to do with the PLC. The GT11 didn't like having voltage spikes I guess. The loose wire was in a remote spot and was not visible. no excuses though. We all made it harder than it had to be. thanks everyone