Faulted 1200 Micrologix

HI,
I'm trying to figure out why a 1200 Micrologix keeps faulting. S:1/13 = 1 and major error S6=20H. I just inherited this machine and have no documentation. I see in notes left behind that processor has faulted in the past and they noted weight overscale. The bulk of the work this 1200 is doing consists of weighing product. 4 Load cells into 4-20 signal conditioners into AI on the 1200. I see N7:0 and N7:1 at 32767 but S5/0=0 after the fault. This is my first 1200. I usually use 1000's for smaller projects but I admit that the programming in this more complicated than I'm used to.

Can you post the program?

It sounds like a math overflow fault although I don't know why S:5/0 shows 0. For PLC5s, SLCs, and Micros I always have a unlatch S:5/0 as the very last instruction in the scan, placed after last JSR of LAD2. This prevents processor from faulting when a math overflow occurs, typically caused by a divide by 0.

This obviously doesn't resolve the problem that is causing the math overflow but, at least the processor won't fault and the rest of the program can continue on.

Here is the file. The errors had been cleared at this point. This is a machine that has been recently moved and the riggers never secured the load cells during the move. My first thought is that the load cells are out of calibration forcing a math error in the PLC. I've been doing a lot of reading and have a few things to try on Monday to narrow it down in the program. Biggest pain is that I constantly am losing comms to the processor which is making everything take forever.

What are the values of the other bits in s:5? Bits 0 through 7 can all indicate a problem. One example is S:5/2 which indicates a control word fault (R6) from some instruction that uses it. In your case, possibly the FLL instruction. You would then look at the error value of R6:0 after the fault.