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Dear Listers,
I am using Siemens S5-135U with CPU type 928B. An EPROM is provided at its slot for pgm backup. Recently one bit of the PLC output is broken/damaged and I need to do minor modification to assign new available output for
replacement.
I modified the program and did the following to transfer the modified pgm to the PLC:
1. Switched off the PLC and removed the EPROM module.
2. Switched ON back the PLC and transfered the modified pgm to the PLC.
3. A msg "Program Exist in EPROM" appear on the screen and pgm transfer was aborted.
4. Since the first transfer attemp failed, I then performed an overall reset on the PLC followed by manual cold restart to erase contents of the RAM.
5. When I tried to transfer the modified pgm again, the same msg "Program Exist in EPROM" and program transfer was aborted.
My questions, Why I could not upload new pgm into the PLC? EPROM has been removed and Overall Reset was carried out but yet the user program still
exist in EPROM! Appreciate your valuable inputs.
Best Rgds,
Shamsul Kamar
Federal Power Sdn Bhd
I am using Siemens S5-135U with CPU type 928B. An EPROM is provided at its slot for pgm backup. Recently one bit of the PLC output is broken/damaged and I need to do minor modification to assign new available output for
replacement.
I modified the program and did the following to transfer the modified pgm to the PLC:
1. Switched off the PLC and removed the EPROM module.
2. Switched ON back the PLC and transfered the modified pgm to the PLC.
3. A msg "Program Exist in EPROM" appear on the screen and pgm transfer was aborted.
4. Since the first transfer attemp failed, I then performed an overall reset on the PLC followed by manual cold restart to erase contents of the RAM.
5. When I tried to transfer the modified pgm again, the same msg "Program Exist in EPROM" and program transfer was aborted.
My questions, Why I could not upload new pgm into the PLC? EPROM has been removed and Overall Reset was carried out but yet the user program still
exist in EPROM! Appreciate your valuable inputs.
Best Rgds,
Shamsul Kamar
Federal Power Sdn Bhd