have a very intermittent 56 fault, it will run a week, then fault 3 times within a couple minutes and shut down. it will run a couple days and do same thing, never seen it happen, replaced various relays, dsp board, it has a dsd312 drive, and it has no stored faults, so don't think it is an actual drive fault. also using fltn command, the last time it happened, it was floor level, with velocity at 0 it faulted on a 56 2 times within a minute or so, then it took off for a long run, 19 floors, it almost made it to the top, and logged a 56 at 451 fpm. this one is killing me, been going on for a month now. any ideas? also been thru m contractor and auxiliary contacts

Have you replaced the DE PMI module? What about MCF 7/4 contact?

Is C1 using a noise suppressor?
Is the C1 contactor spreacher CA6-85?
Is PS1 manufactured by Todd?
Check the wiring from your gate finder board.
I know you said the velocity was 0 but I think there was some trouble with the original encoders.

Find the drive page in the prints that has the 1M contactor. Replace each module and go over every contact on that page.

thanks guys, i replaced the wdpf output module in mcf coil circuit and it has lasted 2 days with no errors, i will try your info out if it comes back in thanks again

well lasted 4 days. then 56 error again. again car parked. no demand no velocity.
indertwetrust i replaced the DE input module, and the ES output module. will see.
sometimes you just got to love these damn elevators.

Try changing the velocity encoder

well replaced de input module, and es output module. 5 days with no errors. guess i should have kept it simple, and replaced de input module first will see looks good now. thanks indert.