Fanuc 0-m zero return problem

[jlong58]

Hi; I just discovered this forum a few days ago and have been doing a lot of reading in the archives. Wow. What a lot of knowledgeable people are here.
I'm hoping someone will be able to help with a problem I am having with a Johnford vmc 2020 mill with a fanuc o-m controller. The controller has a zero return button on the console, but after powering on the machine, when I try to zero return with the button, the x axis over travels. I can call a G53 X0Y0Z0 and the axis' go to machine home with no problem. I have also discovered that if I call a G28 X0Y0Z0 it acts exactly the same as with the button.
I work for a large company, and we just recently got this machine from one of out other plants that was closed, so there is nobody here who knows any more about it than me.
Any help will be greatly appreciated.

[not an expert]

Power the control off. Hold the "P" and the "Cancel" button down. Power up the control holding those two buttons until the CNC comes ready. Release the buttons and perform ZRN. Should work after that.
P/Cancel power up negates the stored strokes at power up.

[jlong58]

Ok, I tried the power up while holding the two buttons. After doing it, I tried to zero return with the console button. It didn't throw an error this time, but it over traveled on both the X and Y axes. I had to hold the ot release button while pushing jog to get them back.
Any other suggestions would be welcome

[CNCRim]

my suspect you had machine table too close to machine zero home..... then try send machine home that's why it's give you an alarm.

[tobyaxis]

Originally Posted by jlong58 Hi; I just discovered this forum a few days ago and have been doing a lot of reading in the archives. Wow. What a lot of knowledgeable people are here. I'm hoping someone will be able to help with a problem I am having with a Johnford vmc 2020 mill with a fanuc o-m controller. The controller has a zero return button on the console, but after powering on the machine, when I try to zero return with the button, the x axis over travels. I can call a G53 X0Y0Z0 and the axis' go to machine home with no problem. I have also discovered that if I call a G28 X0Y0Z0 it acts exactly the same as with the button. I work for a large company, and we just recently got this machine from one of out other plants that was closed, so there is nobody here who knows any more about it than me. Any help will be greatly appreciated.

Originally Posted by jlong58 Ok, I tried the power up while holding the two buttons. After doing it, I tried to zero return with the console button. It didn't throw an error this time, but it over traveled on both the X and Y axes. I had to hold the ot release button while pushing jog to get them back. Any other suggestions would be welcome

Do you have a Reference Manual for the Fanuc Control and the Machine Tool??

Try Homing the machine like you did the Last time but move all Axis XYZ to the center of their travel limits. This is just to make sure you weren't too close to the limit switches.

Read the Fanuc Manual to see if there are any Parameters that you would have to change.

Also Check the Parameter Diagnostic to see what changes during Homing of the Axis.

One other thought. When you Home the Axis be sure that you don't have to set a G92 X0Y0Z0 in MDI Mode.

Cheers!!!

[jlong58]

I finally had a chance to try it again today, and it worked! It now zero returns perfectly. Thanks so much for the help.
I've got a couple of other problems with the machine, but I'm hopeful to find the solutions in the archives of this forum.
thanks again

[bob1371]

Here is some additional info on the Om control that may come in handy.

Diagnostics
#452 Turret adjust switch. Make all 1's then cycle estop to clear tool clamp alarm and allow you to tool change to another tool.

#016 X axis home limit (Bit 5)
#017 Y axis home limit (Bit 5)
#018 Z axis home limit (Bit 5)

#720 X axis alarm bits
#721 Y axis alarm bits
#722 Z axis alarm bits


Parameters
#700 X axis soft limit +
#701 Y axis soft limit +
#702 Z axis soft limit +
#703 4th axis soft limit +
#704 X axis soft limit -
#705 Y axis soft limit -
#706 Z axis soft limit -
#707 4th axis soft limit -
I believe these are right. May have the +/- backwards.


#535 X axis backlash adjustment
#536 Y axis backlash adjustment
#537 Z axis backlash adjustment
#128 Tool # (actual tool in spindle)
#129 Tool # (number of tools magazine will hold)
#9122 Tool Change spindle orientation adjustment. Minus=CCW Plus=CW
#22 Home Position Memory X=bit 0, Y=bit 1, Z=bit 2

Bob

[tobyaxis]

This will come in handy, Thanks!!!!!