MMC was corrupted.
So how does that happen? Simply by downloading application...
In my case it was few input cards that have been accidentally mapped to wrong address (after testing another input card). I changed the addresses back, compiled and downloaded corrected application. Download was declared success but PLC would not run.
I tried to change it back and download but this didn't work. Once MMC is corrupted there is no getting rid of:
- System Data
- System Blocks
- safety program
Other blocks can be deleted or transfered to MMC without problem but system data and safety program or it's remains would not go away (13:4462 - "Can't delete safety attribute"). So I tried memory reset through Simatic Manager (this is corrective action according to help) as well as using CPU switch, then I tried downloading older project, creating some dummy project with different hardware confing - all without luck.
Once I got hold of USB promer and MMC blocks were deleted and card inserted back into same CPU, same project (still with the mentioned NetPro consitency error) downloaded and worked ok...!
But while wrestling with this I was trying to get Siemens tech support to help with the issue, I've sent them bunch of emails with screenshots, diagnostic buffer dump, part numbers, software versions etc. It didn't work - Siemens tech support refused to provide answers unless they get complete project (and unfortunately I can't give them that). They say there might have been some note on this, maybe even fix for it and if I want to do something about it I should try saving as and reorganizing (slow) or reinstalling or upgrading software but they wouldn't even try looking this up... I did everything but reinstall or upgrade. I don't mind upgrade if I'm not in the middle of comissioning -unless there is a confirmation that this was addressed (I can install it now, the heat is off...) but I do have problem when documented recovery procedure doesn't work and tech support will not even investigate...
They also have no comment on why application compiles without error, downloads without error and S7 states that download is sucessfull when CPU doesn't run and online compare shows that MMC content is not matching offline project.
They did have comment on not working memory reset (memory clear/reset and memory format - neither can clear MMC and restore factory settings even if CPU and MMC are defect free):
"So many people have asked for this already..." (300 series CPU user manual, chapter 8.4.4...)
Apparently this may work if MMC doesn't get corrupted in download, if CPU application has no special attributs like safety and if application on MMC is for completely different CPU (what?) or if you have USB promer or Field PG.
Overall, I'm more than disapointed (but not surprised...).
Give me any other brand any time...
