TCP 5-axis kinematics

In my setup, with step/dir interface via 7i76 to the servo drives, LinuxCNC does not see any encoder feedback for motion control. I do happen to have access (CanOpen over Ethercat) to the rotary position and a few other pieces of information as well as torque control as well - but for all practical purposes its as if LinuxCNC sees no encoder information.

Or am I missing your point Andypugh?

@dgarrett will check in the next day or so - ok?

If you test dgarr/homing_h successfully and report so
it can be merged, i will work on adding support for
something like HOME_INDEX_NO_ENCODER_RESET as you
suggest

Deal

plopes9000 wrote: In my setup, with step/dir interface via 7i76 to the servo drives, LinuxCNC does not see any encoder feedback for motion control. I do happen to have access (CanOpen over Ethercat) to the rotary position and a few other pieces of information as well as torque control as well - but for all practical purposes its as if LinuxCNC see's no encoder information.

LinuxCNC always see some feedback, and it uses this for the homing process.
I imagine that currently it is the internally-generated stepgen feedback. If you were to use the absolute position from the drive in place of the stepgen feedback then you might be able to use that for homing.

If it is true-absolute then this ought to work as-is. If it is single-turn absolute then you would need to hack things using a position.txt file (saves shut-down position) and HAL logic to infer the current position from the encoder feedback and a calculated number of complete revs from position.txt. (this does work, and is actually built-in to the 7i49 resolver driver)

andypugh wrote:

plopes9000 wrote: In my setup, with step/dir interface via 7i76 to the servo drives, LinuxCNC does not see any encoder feedback for motion control. I do happen to have access (CanOpen over Ethercat) to the rotary position and a few other pieces of information as well as torque control as well - but for all practical purposes its as if LinuxCNC see's no encoder information.

LinuxCNC always see some feedback, and it uses this for the homing process.
I imagine that currently it is the internally-generated stepgen feedback. If you were to use the absolute position from the drive in place of the stepgen feedback then you might be able to use that for homing.

If it is true-absolute then this ought to work as-is. If it is single-turn absolute then you would need to hack things using a position.txt file (saves shut-down position) and HAL logic to infer the current position from the encoder feedback and a calculated number of complete revs from position.txt. (this does work, and is actually built-in to the 7i49 resolver driver)

You are right that that the mesa driver stepgen is providing the feedback - I recall checking if there was a pin on the mesa driver to reset the counters - unfortunately there wasn't any.

The CanOpen rotary position is single-turn absolute ... however since its CanOpen over Ethernet, I do not think I would get fast enough updates for high speed motion - its fine for homing at slow speeds though.