CPU-E light

Can anybody help?
I am currently trying to solve a problem on a FX - 48MT plc. The problem is that the machine starts ok then half way into the cycle it stops and the CPU - E LED lights up and i have to reset the plc to get the machine to start. I changed the battery but it still did the same. I then swapped the plc for a good one and it did the same thing at the same time in the machine cycle. I use GXDEV can anybody help me what to look for?

Check diagnostic registers

Use GX-Developer to monitor D8004. That will give you a 4 digit code that is the error code.

From there I would go to www.meau.com and download manual JY992D48301 and look at Chapter 6. It will give all the different error codes and their meanings. If you have a problem deciphering what you see, post it here and I will try and help.

CPU-E almost never indicates a hardware problem. Some command in your program is working on data which it can't understand. The fact that the error switched PLCs confirms it's a program problem, not hardware. Check the D8004 address and the manual as indicated by SteinCollector.