Denford Triac ATC Problem

My Denford Triac with Fanuc OM control has developed a Tool changer fault today, when tool changing the carousel goes past the tool pocket requested and keeps spinning until it times out.

I have adjusted the sensor that makes contact with geneva wheel and put multimeter on the block that the sensor is connected to, I get 0 then 5v(or just under) repeatedly as the wheel turns.

If I use the manual ATC rotate buttons on the control, the wheel turns twice and indexes round one position but if I request an T# M6 within a program or MDI it just spins round.

Anyone got any idea what the problem might be?

Has anyone got a wiring diagram for the Denford triac with fanuc OM control?

It sounds like a problem with the controller ladder, rather than a sensor problem, given it indexes correctly with the buttons.

These drawings? http://www.denfordata.com/bb/viewtopic.php?f=15&t=2651
There are quite a few Fanuc downloads in the download board on the denford forum.

Thanks for that, looked all over that forum but somehiw missed the downloads section. Got the fanuc om service manual which has electrical diagrams and ladder diagram. You are right when using the manual index buttons the sensor flashes twice on the ladder but when calling an m6 the sensor doesnt register the rotations. Any idea why this might have changed suddenly?