S7313C - Fault ?

Hi all
I have an S7313C plc that is giving me some trouble.
The SF light is flashing when I insert the MMC ?
It's not a fault int he program as I have swapped the MMC with another PLC and the card/program fuctions in another PLC of the exact same model.
I can get online and it all seems good , but as soon as I push the MMC in , the SF light starts flashing.

Ideas ?

When the SF lights flashes, the CPU must have some messages in the diagnostic buffer. start by looking at them and maybe post them here.

I can't get online when I plug a MMC in
Without a card plugged I have done a hardware diagnostics and it all looks OK.

When I plug the card in , the SF light is fully on and the STOP light is flashing.
And I can't get online.

PLCKeef said:

Hi all
I have an S7313C plc that is giving me some trouble.
The SF light is flashing when I insert the MMC ?
It's not a fault int he program as I have swapped the MMC with another PLC and the card/program fuctions in another PLC of the exact same model.
I can get online and it all seems good , but as soon as I push the MMC in , the SF light starts flashing.

Ideas ?

Click to expand...

Why don't you grab the MMC from the "other" working unit, plug it in the failed unit and see if it will produce the same results.

Yeah I've done that , it's not the MMC as it works in other PLC's and Ive tried different MMC cards in this particular PLC with the problem.

When the stop light is flashing it is requesting a memory reset

I've tried a memory reset , it didn't fix the problem.
I can get online ot the CPU without the MMC inserted , perhaps I need to reset the hardware configuration ?
As soon as I insert any MMC card I lose comunications.

Perhaps one of my students has done something to the hardware configuration ?

Hm I have had this problem a while back, I know I tried a lot of memory resets, with and without the card, power off-on etc. eventually the stop light stopped flashing and I could come online again (with the card). But don't really recall what the exact sequence was I used... stupid me.

How are you communicating? Tried formatting the card?

grtz

You cannot operate an S7-300 without the MMC card.
If you insert an MMC card from another PLC, you must be sure that the CPU types are similar, otherwise it will not be accepted.
Try with a fresh new MMC card. If that goes OK you know that the other MMC is corrupted.

To clear a corrupted MMC you should be able to do it by a reset in the CPU, but I have heard others having problems with this.
I have a USB prommer, and I can use it to clear an MMC card including the System Data Block. The MMC may be so corrupted that even this is not possible. In that case you can have it fixed at Siemens (not worth the expense unless it is a really big card). You may also try to look for a MMC utility that can restore a good image on the card - not worth the risk unless the card is otherwise not possible to save.

And do NOT format the card in a PC card reader !

And do NOT format the card in a PC card reader !

Click to expand...

that was not what I meant, really, I meant "memory card -> delete" from Simatic Manager. sorry for being not clear.
But anyhow I don't really think it's the card's fault following PLCKeef's story.

Had a similar problem a while back. Electrician at the plant took the MMC out and used the erase on his #2 pencil to clean the contacts as a last ditch effort. Worked great after that. Maybe some of the contacts inside the MMC slot are not making good contact on that CPU?

Thanks guys
I have identical PLC setups and cards , the card works fine in other PLCs. (313c)
Ive tried different cards , even a brand new one I have as a spare after some student stole one , and no luck.


I can get online without the card inserted , diagnostics say the CPU is OK etc, but as soon as I insert the card I lose communication.
I could perhaps pull it apart and clean up the contacts.

Tried to simulate the problem somewhat today.
I put an MMC in a S7-313-2-PN/DP and downloaded a valid configuration for that CPU.
Then I put the MMC in a 315C and fixed it by doing a memory reset in the following sequence:
- stop light flashes
- hold the mode switch down to MRES, stop light flashes
- when it stops flashing release the switch and
- hold the mode switch down again (right away),
- stop light flashes fast then slow
- when it stops flashing release switch and stop light should stay steady now.

MRES 1 time did not work; hopes this will help you.
Also, without the MMC card you could communicate right? then you should also be able look at the diagnostig buffer to see what went wrong before with the card, it should tell you. look at my diagnose.txt (event 7)

grtz