Simatic S7-414-3 CPU

I've never worked with that PLC, but I know for sure that in others, either a configuration problem or an I/O fault will stop them, go ahead and replace it, check that the config. matches and come back to tell us that it's all right.

Are you sure the CPU is faulty?

Most CPU's have major & minor fault tables that can be only be reset/cleared via the local communication access port using a laptop or HHT.

Major faults instantly shut down CPU program execution and cause the CPU to go into "DIM" state. (Still on line but all functions are suspended and all of the I/O is in the "off" state.)

Also: In many units the CPU minor fault table is not a "first-in-first-out" self clearing table and if the fault table memory register becomes "Stuffed" (full) the CPU will shutdown and go into "DIM" state until the fault table is cleared.

If you want trouble-free operation the CPU fault tables should be reviewed often and all errors as well as fault codes should be investigated, the issues corrected, and the fault table cleared/reset.

The factory IOM and troubleshooting guide contains information and instructions on how to identify and correct these issues.

Dear sholiscan/yehla,

Thanx for your valuable inputs. Replying to sholiscan, I can say that we were sure that the CPU was faulty because when we put it online it showed some blocks only and also no logic in them. While in offline mode it was showing the whole blocks with logic. It was going to run in online mode but no block was going online. This was very strange behaviour. We also checked the diagnostic buffer. So decided to change it and then no problem came. only red indications of BUS2F and EXTF.

Best Regards

[irrelevant part]
(<< Google search to ident what you guys talking about)
► S7-414-3
► (*) profibus dp asm (actually i ment the below)
► profibus dp program sample
(>> the sites of interest below (i have some PCL experience - not with the Siemens))
(*) Link_1 <> Link_2 <> Link_3 <> (Forum srch test) Link_4 <> (? didn't they help ►) Link_5

[relevant part]
Last week our CPU S7-414-3 got faulty due to profibus problem.
_{e.g. "my program didn't work coz of a coding err." (whitch was missing empty ELSE clause in generic dynamic obj. dipose routine -- everyone guessed it already from "quoted spec." i assume)}

_{it take to read through the whole language spec. -- just to realize that there is no syntax bugz -- then i mapped the irregularities -- and thought ?perhaps -- and it was the case -- 24h error tracking -- i knock my head to wall denoting "Thank you Boreland!" (this is where i became so stupid ... what about the little my computer still works )}

I think this is neither the problem of the PLC nor the encoder. glowing of red LEd in encoder in place of green LEd means this a profibus problem. Maybe the prfibus has got cut between the encoder and the device connected to PLC before encoder. Maybe there is noise entering in the profibus just before the encoder ot its terminal is loose. this may also come if encoder is the last node in the network and its terminating resistance is open or switch position is changed to open.