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CPU not detecting MMC

2/1/2011 8:24 AM	Rate (0)
ZakirSayed Posts: 39 Rating: (0)	Hello every body I have come across a problem where 317-2DP CPU was not detecting MMC and showing system fault. And also MMC placed in that CPU was corrupt ,and i came about that when i placed same MMC in new CPU with selector switch at STOP position ,then that particular CPU goes into system fault i.e. SF LED. Also i placed new MMC in that faulty CPU,it was not getting detected.
ZakirSayed Posts: 39 Rating: (0)
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Joined: 3/21/2006

Last visit: 1/10/2026

Posts: 10247

Rating:

(1183)

Hello,

Are you using "Siemens" MMC? Take a look at -

	Why is the MMC no longer recognized by SIMATIC devices after it has been formatted in a third-party device?
	With MMC (Micro Memory Card) slotted, why does the STOP LED blink on the SIMATIC S7-300 CPU?

2/1/2011 12:22 PM	Rate (0)
ZakirSayed Posts: 39 Rating: (0)	When i replaced corrupt MMC witha new frsh MMC card and tried to download. CPU was not detecting MMC and still STOP LED was flashing. Also i memory resetted but still STOP LED was flashing. I wanted to know that a CPU can get corrupt.
ZakirSayed Posts: 39 Rating: (0)
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2/2/2011 11:37 AM	Rate (0)
Muldereric Posts: 16 Rating: (3)	Like UMENCHO implies, you have to use original Siemens Micro Memory Cards and not the so called Multi Media Cards you can buy in every store around.
Muldereric Posts: 16 Rating: (3)
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2/2/2011 1:52 PM	Rate (0)
PLCnoob Posts: 26 Rating: (1)	and dont format it with windows
PLCnoob Posts: 26 Rating: (1)
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2/3/2011 5:59 AM	Rate (0)
Navnag Platinum Member Joined: 11/21/2007 Last visit: 1/8/2026 Posts: 2327 Rating: (309)	Hello If you plug an MMC which was earlier being used in a different CPU model, then also you can have this problem. e.g. if you remove a MMC for CPU 313C and try to use it in CPU 315-2DP, then also similar problem occurs. You need to Format / Reset the MMC in the New CPU. Pl see the link below : http://support.automation.siemens.com/WW/view/en/29801950 Regards Navnag
	There is no such thing as the last bug in a program There are no stubborn bugs, There are only stubborn Debuggers.
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