Denford Software & Machines

I have a Zeroturn Fanuc OT (B) 1987 and the X axis cannot find its datum position. I.e. it over travels the datum switch by around 40mm and then I get the Over Travel Alarm.

I have changed the Datum switch to no avail

It could be a broken wire somewhere or faulty Input. From our drawing A3-310521, 24V is supplied to one side of the datum switches (N/C) (X and Z axes). Out from the datum switches the wires go to connector plug M1 (See below for details)

X datum Switch - Connector M1 - Pin 38 - Wire blue- Diagnostic X16.5
Z datum Switch - Connector M1 - Pin 39 - Wire red - Diagnostic X17.5

If you can access Diagnostic X16.5 from the control panel, try activating the datum switch by hand, you should see the value changing from a 1 to a 0 (Or vice versa, it the change you are looking for). If the Z axis datums OK, look at Diagnostic X17.5 and see what that does when you activate the Z axis datum switch

I had a similar problem on a Fanuc OT. solution was to boot up while holding down CAN and COMMAND buttons

I have never heard of CAN and COMMAND buttons, but I made the following notes

Fanuc OM controller
”Z” movement


In transit the “Z” axis on a Fanuc OM Triac may gradually move out of position i.e. feeding down the ball screw. To cater for this when booting up the machine, keep the P and CANCEL button (Disables software limits) depressed until something appears on the monitor screen. Then you can jog 50mm away from the axes datums and then HOME as usual

Sorry thats right! CAN,COMMAND turns off the screen my mistake!

The error code "SLI Over error code 413" Means, Quote from the Fanuc Service manual

"The contents of the axis error register exceeds 32767, or the velocity command value of DA converter is outside a range of -78192 - + 8191. This error is usually caused by various setting failures"

We think that the motor is been asked to be moved by the controller but is getting no feed back.

1.You could try powering up the Cyclone, pressing in the e stop button and trying to turn the X axis manually to see if the position readouts change on the screen.

2. Check all fuses and contactors are OK

3. Could be a broken wire

Is it possible that the motor/slide is jumping when it is powered up.
Try & mark the position of the slide. If it moves slightly when it is powered up it may be that Parameter 556 (I think) has a large value. Try setting to 0. Parameter 555 is for the x axis.