Mmc

Good day
i had Siemens S7 300 PLC
i need to install new MMC on it
did the old one will keep having the existing apllication program on it
did the new one will upload the existing apllication program
Kindly advice

also is there is any way to be sure that the PLC existing application program not to be effected
thanks

As far as I understand, you are going to replace an old MMC with a new one.

The old MMC will still have the application code on it.
It won't be erased until you erase it.


When you plug your new MMC, your CPU will load the new user program from the MMC.

The application program is always loaded from MMC.
So, whenever you unplug MMC, your CPU will stop because it doesn't have a program.

What are you trying to do?

i am trying to to mdification in the exiting program but with keeping the orginal as it is
also as i know that the PLC only uploading the program from the MMC just in case of total reset is that Correct?
kindly advice

Osama,

From what I understand, You need not have a new MMC to modify the program.

What I do is Upload the existing program in a new project and name it say, "Proj1Upload081117".

Then modify it as required, save it as "Proj2081117" and then download it.
I hope this helps.

Regards,
ali.