Centroid Community CNC Support Forum

A question was asked in another thread if it was possible to display the spindle angle on the DRO. If you have a spindle encoder mounted on your machine, you can do this with a manual axis. This will work for a mill or lathe and could be useful for things like single point broaching of multiple keyways or splines etc.

This is done my manually editing the parameters and machine setup so it will be over written if you use the Acorn wizard to make changes afterwards.

First, MAKE A BACKUP!!! F7 Utility/F7 Create Report

Then open the parameter setup (F1 Setup/F3 Config/F3 Params) and not the value of the spindle encoder counts P34, and the spindle encoder axis #, P35.

Now select and axis to use for the manual display. I chose axis 8 on my machines since I would be unlikely to use that for anything else in the future.
Now, change the Axis Setup Parameter for the axis you chose to 11. I my case I set P169=11. Change the Encoder Setup Parameter for the chosen axis number to be the same value as P35 (i.e. if axis 8, change parameter 315 to have the same value as P35).

Hit F10 to save the changes. You will get a warning message about a duplicate encoder entry; this is safe to ignore. You will also be told you have to restart for the changes to take effect, hit F2 for reboot later and escape back to the home screen.

Now, we need to set up the rotational display. Hit F1 Setup/F3 Config/F2 Mach/F2 Motor. Cursor down to the line for the axis you chose earlier. Change the axis label to "M", set the" Motor revs/in" to .002777777778 (i.e. 1/360), set the "encoder counts/rev" equal to the absolute value of P34. If P34 was negative, then cursor over to the "Dir Rev" column, and use the space bar to toggle it to "Y". Hit F10 to save.

Escape back to the home screen restart the computer and the Centroid controller.

You should now have a manual axis that displays the spindle rotation angle. Home the machine and it should be set to 0.0000°. Rotate the spindle by hand and verify that one rotation is 360°.

You can zero the spindle angle DRO by using MDI and entering M26/M and pressing cycle start. You can also zero the degree DRO or preset it using variables in MDI.
To zero the DRO, set the DRO value to the MCS Value for the axis you chose earlier. I.e. for a manual axis 8, you would enter #3200=#5028 in MDI and press cycle start. To preset and axis add the preset amount to the MCS value. If you changed "Dir Rev" to Y above you'll need to subtract the preset amount from the MCS value.

For example, using axis 7 as the manual axis and presetting to 123.456° when direction reverse was chosen (negative value in P34), your would type the following in MDI: #3100=#5027-123.456 and press cycle start.

If you were using axis 8 and had a positive P34 value and wanted to preset the DRO to 987.654°, your would MDI the following: #3200=#5028+987.654 and press cycle start.

You can turn this display on and off by simply changing the axis label on the motor setup screen between "N" (no display) and "M" (display) at any time. You do not need to change any of the other parameters back.

Thanks heaps, I will give that a try.

Hi again.
I have finally found time and followed the instructions to set up the manual axis. I now have the axis display and it is zero however it does not increment with the spindle. Doesn’t increment at all with any axis. It also will not let me do any value on steps/rev less than 0.1 (I’m using metric) when setting that step. I’m sure It’s a simple error on linking the parameters to each other but I’m at a loss as to where. Any help would be appreciated as always. I will post a report when I get back to the machine to help diagnose the issues. Cheers .

Quick update, went back to machine and it worked perfectly. Unsure what the issue was but it is now working awesome. Thanks heaps to all that helped

It is working for me.
I am using metric.
I had only to put in 360 instead of .002777777778 for some reason.

Thanks a lot.

Just a quick tip I use. If the manual axis comes up M****.**** go to MDI page and type:- M26/M to reset the zero position for the axis. Occasionally the DRO will not read out when it opens. You can also write a macro for zeroing the manual axis to the index pulse, you will find that discussion and code in the C axis ZRI posts.