UCCNC - Rotary axis homing ?

[crjohnson]

Hi all,

I am designing a 4th axis for my machine and am just wondering how UCCNC handles homing of rotary axis?

I looked through the UCCNC software user guide and didn't see anything. If UCCNC does not have anything built in for this, how have people done this on their machines?

The process I had in my head was that the axis would rotate until a sensor is detected (record the position), then rotate the opposite way until another detection is made, then find the mid-point between these 2 measurements. Is that correct or is there a better method?

I have not decided what sensor to use, I was hoping to use the panasonic PM-F45-P photoelectric sensors (used on my other axis), but I cannot physically fit them in. It looks like I will have to use a round inductive type sensor.
Any help would be appreciated!

[dezsoe]

Of course, you can home all the axes including the rotary ones. Here is how it works:

1. If the home sensor is active then skip to 3.
2. Move the axis towards the sensor with "homing speed up" until the sensor gets active.
3. Move the axis away from the sensor with "homing speed down" until the sensor gets inactive.
4. Move the axis by "homing back off" units.
5. If the "auto set" is turned on then write the "write offset on homing" value into the machine coordinate of the axis.

You should set the speed up to a faster feed rate to find the sensor quickly and the speed down to a slower to get precise reference point.

[crjohnson]

Thanks Dezsoe, I should have known they would behave the same as the other linear axis..

Do you happen to have much experience with types of sensors and rotary axis though? I am going to use a HD CSF-32-50-SP harmonc drive and a delta 400w servo, I feel these parts should do a very good job so I would like to use a homing system to match their performance etc.

Do you know if there is a macro to do the homing sequence I mentioned in the first post?

[crjohnson]

Dezsoe: does the software ignore the homing sensor when not 'homing' ? Ie. if i wanted the axis to rotate 2 revolutions, it will trigger the sensor twice. Will that cause a limit switch error?

I've never tried tripping a homing sensor when in normal operation but may try it next time I have the cnc running. Cheers

[cncdrive]

Only limit switch input stops the machine when not homing, the controller ignores the home input when not homing.