MPG working with joint but not with axis ???

Ahh that what Rod mentioned.
What do you meN nor recommended?
I am surprised pncconf did not connect Hal in that way actually.

AFAIK most (if not all) industrial robots do not allow jogging before homing all the axes. I have an older Adept cartesian robot as well as a Yamaha cartesian robot and neither of them allow any motion before homing.

I can see a few reasons why:

- The position is unknown before homing (except with absolute encoders). Software limits are then useless, DRO is then useless too. Limit switches may not work if you're past the detection point.

- With gantry machine, or any machine with more than one joint per axes, problems may happen if a single joint is moved (ex racking)

- With a correct homing procedure there is simply no need for jogging before homing and in fact LinuxCnc has everything needed for that.

Interesting, I have a old CNC mill that allows axis jogging before homing and does not have absolute encoders. You can even set a 0 XYZ work position run G code but at a reduced maximum feed rate.

I would guess that on initial setup of the mill the home positions are set, the XYZ travels are hard coded in the software and from there on the position of the axis are saved in memory. If it is turned off it knows where it is on the next power-up.

cmorley wrote:

That allows you to jog In joint mode before homing.

You must home to jog as an axis.
 

I was just restoring my BP after a PC crash and found this thread with google and you saved me from pulling my hair out.

JT