Centroid Community CNC Support Forum

I have a RF-31 mill running Clearpath servos which are connected to H2 and H3 per the Acorn_rev4 Multiple Clearpath SDSK schematic.
Everything is running great. I want to add a "independent" Clearpath servo to move the Mill head up and down the column by adding macros
to the VCP. At first I connected the servo as a fourth axis and realized it wasn't going to work that way. I have been searching the forum for some answers with no luck. Here is what I would like to do. Create two "buttons" on the VCP for Up and Down. Use the PWM signal from H6, pin 14 "Output 2", for the Step signal and relay outputs for direction (Up and Down). I am not sure if you can use H2 and H3 in combination with H6. I am happy to
continue trying to figure this out, just want to know if this is possible?

Can you use PWM signal from H6 while also using H2 and H3?

Is there anyone on this forum who can answer this question?

Do you need more information?

At first I connected the servo as a fourth axis and realized it wasn't going to work that way.

Why not? Set as linear axis. "W" would be my preference. Use the 4th axis jog arrows to move the table. If there is a way to home that motion, you should have/calculate actual position

PWM (Pulse Width Modulation) would be very hard to use as a typical stepper/servo step signal. By definition, PWM is a continuous series of pulses with the width of the ON portion of each pulse variable. In Wizard, you set the Base Frequency (1 - 24,000) and choose between 100 and 1000 for the PWM S command. I'm guessing about this next part. If the Base Frequency parameter is set to 100 and the PWM S parameter is set to 100, then each pulse is divided into 100 parts and the S command controls how many parts of each pulse are high and how many parts of each pulse are low. For instance, if the S command is set to 25, then the ON portion of each pulse would be 25% of the pulse width. If the S command is set to 50, then the ON portion of each pulse would be 50%. If the S command is set to 75, then the ON portion of each pulse would be 75%.

The polarity of the signal can be inverted in Wizard.

In my mind the PWM signal would be used with devices that require a continuous digital pulse for speed control, such as ClearPath MC series servos.

Hi Gary and Mike,

Thank you for the feedback. If I can find a way to keep from having to "home" the W-axis, that may be my
way to go. This servo will be rarely used. I do not plan on moving the mill head unless I have too due to the
size of the part. The servo would remain at a constant speed while moving up or down. I was just looking
for a way to integrate it with the control panel. Basically I am looking for a way to control the servo with out
affecting the X, Y or Z axis.