Thanks all for the feedback. I really like the idea of letting the drive do everything.
@JPL
Yes, it's a 2098-DSD-010X (indexing). Was not aware that only the X models had home to sensor, fwd/back to marker. Although I did find out the sercos models can have the sercos interface disabled which opens up additional IO.
Should be easy enough to adjust the motor-drive coupling to get the index pulse half a rotation from the proxy home switch trigger point. The whole thing is based on a 50:1 harmonic drive and the proxy is triggered by a flag on the output.
@rodw -
"nontrivial" = not going to attempt this, but thanks for the reminder. Not a programmer; maybe some day.
@Andy -
I don't want the A-axis homing automatically with the X/Y/Z. I tend to leave a trunnion table on it and there may be interference or a setup on it that needs to be broken down or adjusted before 360 rotation (i.e. tall part that would smack the table at 180 degrees). But you've prompted me to read the INI file homing section and double-check the basics...
Sanity check...
- Homing proxy only connected to drive
- Drive input "Start homing" connected to LCNC output
- net A-HOMED <= joint.4.homed
- net A-HOMED => hm2.something.7i76.output-nn
- INI file
- A-axis set to immediate homing
- HOME_SEQUENCE = (blank) so homing is not part of the X/Y/Z sequence
- Home offset, if any, is programmed in drive (Offset Move Distance in A-B speak)
- LCNC zeros the DRO/offsets when the home-A is commanded, and the drive then goes through the homing sequence. If there's a homing error the drive faults, but LCNC doesn't know anything except fault/no-fault.
Can anyone think of a scenario - user error or hardware failure - that results in Something Very Bad happening?
(Other than homing with a tall part on the trunnion, of course, but I'd deserve that one)
