一.如何删除MMC卡上的数据或程序？
How can I delete the data or program on a MMC (Micro Memory Card)?
You can use the following procedure to delete the block on an MMC in the CPU:
1. The MMC to be deleted is slotted in the CPU.
2. In the SIMATIC Manager, switch to online mode via "View > Online" or by pressing the appropriate button.
3. In the Online window, you select the block folder.
4. Select all the blocks in the folder which you want to delete.
5. Click the "Delete" key on your PC keyboard (you can acknowledge the message that system functions cannot be deleted).


二.31X型PLC插入MMC卡后，STOP灯不停闪烁，怎么办？或如何格式化MMC？
Why does the STOP LED flash on my CPU 31xC when the MMC (Micro Memory Card) is slotted? The CPU does not behave like this with other MMCs.
ANSWER:
The MMC in your CPU is not formatted or contains data that cannot be interpreted by this CPU (e.g. the configuration of a different CPU type or an operating system not compatible with the CPU).
WARNING:
When you format the MMC all the data that is located on the MMC is deleted!
Proceed as follows to format the MMC.
1. Your CPU requests an overall reset (slow flashing of the STOP LED).
2. Put the switch into the MRES position and hold it there until the STOP LED lights permanently (approx. 9 seconds).
3. You must then release the switch within the next 3 seconds and then put it back into the MRES position. The STOP-LED now flashes during formatting.
If the MMC cannot be formatted as described above, then the MMC is defective.
NOTE:
It is only possible to format the MMC if there is data located on the MMC that is invalid for the CPU. Otherwise the MMC is only initialized through the steps described.
More information on the MMC is available in Entry ID: 8861901


其实使用MRES清除的是CPU的工作存储器,并没有格式化MMC卡,当你按照以上要求操作完之后,开关应该停留在STOP位置,如果在这时候把开关打到RUN位置的话,CPU会把MMC卡里的内容再次读入工作存储器,也就是你之前的操作是白忙活了
西门子应该把“开关应该停留在STOP位置”写到“NOTE”里，标题也不应该使用“如何格式化MMC？”