SLC500 EEPROM write protected

I have a SLC500 PLC with a 5/02 (1747-L524) CPU and there is a 4K EEPROM installed in the CPU. When I try to save the program into the EEPROM I get a message that the EEPROM is write protected. What do I need to do in order to be able to load the program into the EEPROM and get rid of the write protection. In other systems we have I have been able to load into the EEPROM with no problems.

Thanks
Fred Johns
Day Timer, Inc.

From the help file

Memory Module Write Protection

Memory module write protection allows you to permanently program the memory module. This option is similar to UVPROM functionality. Once a memory module is programmed with write protection, you can no longer write to it using an SLC 5/03, SLC 5/04, or 5/05 processor.
Apply this protection via the Memory Module Protection dialog box that appears when you attempt to perform EEPROM after selecting Comms > EEPROM.
Click the Normal Protection Control button if you want to reuse the EEPROM Memory module.
Click the Write Only Protection Control button if you want to retain the program in EEPROM and do not want the EEPROM device reprogrammed at any time.
Note for MicroLogix Controllers
These controllers only provide a capability that allows you to select whether or not the communications configuration in the controller should be maintained when a program from a memory module is transferred to the controller. Maintaining this configuration information prevents the loss of communications after the program is transferred.

Apply this protection via the Channel Communication Configuration dialog box General tab.

____________
I guess it was write protected in the writing process.

Write protection is for real

The 1747-M2 is an EEPROM, and can be rewritten many times.

The 1747-M4 is a UVPROM, the old-fashioned ultraviolet-erasable ROM chips. Generally they are only written to once, inside a PROM programmer. Even if you erased it with a UV source, you couldn't write to it while it was installed in the SLC controller.

1747-M11, M12b, and M13 are "Flash EProm" that are writable inside the SLC and as an option can be write-protected so that they cannot be re-written.

The three types of ROM plugs are described in RA Knowbase article 9137 and in the SLC Modular Hardware Style User Manual.

In your case, the only option is to put in a new EEPROM module.

I think the EEPROM that is in my 5/02 cpu is the 1747-M2 but I will have to check in the morning when I go in. If I do in fact have the M2, then should I be able to rewrite over what is already in it.

fredjohns said:

... If I do in fact have the M2, then should I be able to
rewrite over what is already in it.

Click to expand...

Not if it has been write protected. If that's the case as you describe in your first post, then you need a new one. If you need to edit the PLC program and want to avoid faults or having it overwritten by the EEPROM, then remove the EEPROM and turn off any bits that may cause errors when you run the SLC without it. Be sure you have a good battery installed.

Thanks guys, I ordered a new EEPROM today.