Posted 8 Feb 2006 Dear list. I have an FX48MR with multiple additons controlling a piece of insturumentation. I believe that I have a corrupt program on the eprom so I would like to erase the program and reprogram. Unfortunatley I do not have a programmer nor is there is feature in the software controlling the instrumentation to do this. I know there is a way of doing this as I have done it before, I've just forgotten. If by removing the backup battery and leaving the base unit powered up will that erase the program? Or do I need to have it powered down? Thanks in advance for any help you can provide. Share this post Link to post Share on other sites
Posted 10 Feb 2006 You cannot erase an EPROM (or EEPROM for that matter) by removing the battery. To erase an EPROM, you need an ultraviolet light EPROM eraser. The EEPROM is electrically erasable, and you can write a new program to an EEPROM right from within the GX-Developer PLC programming software. If you think the memory is corrupt, I would buy a new EPROM from your local Mitsubishi distributor, download a program to it, and then exchange it for the one in the PLC. Keep in mind you only should remove the memory modules with the power OFF. If you power up the PLC without a memory module, the PLC will use it's internal memory and the program contained there. So if you're not sure what's wrong, you might want to shut down the PLC, pull the memory module, and download the program right into the PLC for testing. Share this post Link to post Share on other sites