thanks for the reply.I am using Flash EPROM (6ES5-374-2K621). CPU of our S5 PLC is CPU 928b. The problem started when our display OP20 malfunctioned. I never had any visualization and decided to check the problem on-line. The machine has no back-up program nor comments. So I upload the present program (for safety) then decided to edit some contacts and when I am about to download it. The error "BLOCK EXISTS IN EPROM" appears. I cannot save the contacts I've changed and cannot put them in the program. Only the Data Blocks are accepted. Can it really happen that some PLCs are protected in such that you can only upload their program but can never edit or download it?
How I wish it was already converted to S7.S5 gives me a lot of creeps and headaches.
Hope you will not be puzzled by my problem. It would be a big help if you could give some suggestions.
rdrast is correct on this, it has been my experience that an S5 with an eeprom fitted will not allow changes to be made, you need to remove the eeprom and burn the 'new' program to eeprom then re-insert it back into the CPU.
The main reason why I removed all the eeproms from our S5 CPU945's.
Thanks a lot guys. I had my christmas vacation that's why I never had the chance to thank you earlier.I'll try the "prommer" you suggested and will keep your posted regarding the developments.
thanks.
My own quote:
Knowledge is power but in order to have one you must also be humble.