Feed per rev G95 way too fast
- sconisbee
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19 Oct 2025 20:36 #336727
by sconisbee
Feed per rev G95 way too fast was created by sconisbee
Hi, Sorry, please bear with me, I'm new here and relatively new to LinuxCNC.I've been converting an old Boxford 240 TCL to LinuxCNC running on a Pi5.
Everything is running fine(ish) there are still some glitches and errors that crop up and the odd latency warning too (stepping is done on an EC300 running remora so I'm not so worried about the latency warning).
However... i've gotten to the point of testing, and for some reason in G95 and feeding at 0.1mm/rev the axis runs at way faster rate, 10x maybe more.Anyone have any idea what is going on? The only other thing to note is that I am having issues with LinuxCNC seeing my index pulse, but it is seeing the count from the single encoder (100 slot disk with a second slotted opto switch for index so not quadrature).
I'm assuming that its possible the feed issue could be linked to that.
The other issue I am having is when i run a program, it won't run through automatically. The only way it will run is by me hitting the single step through button. I'm wondering if that is linked to the encoder also as perhaps LinuxCNC isn't seeing "at speed" so isn't letting the program run?
hal and ini attached. Please forgive the messy files, once they are running right I'm planning on cleaning them up.
Everything is running fine(ish) there are still some glitches and errors that crop up and the odd latency warning too (stepping is done on an EC300 running remora so I'm not so worried about the latency warning).
However... i've gotten to the point of testing, and for some reason in G95 and feeding at 0.1mm/rev the axis runs at way faster rate, 10x maybe more.Anyone have any idea what is going on? The only other thing to note is that I am having issues with LinuxCNC seeing my index pulse, but it is seeing the count from the single encoder (100 slot disk with a second slotted opto switch for index so not quadrature).
I'm assuming that its possible the feed issue could be linked to that.
The other issue I am having is when i run a program, it won't run through automatically. The only way it will run is by me hitting the single step through button. I'm wondering if that is linked to the encoder also as perhaps LinuxCNC isn't seeing "at speed" so isn't letting the program run?
hal and ini attached. Please forgive the messy files, once they are running right I'm planning on cleaning them up.
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- andypugh
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20 Oct 2025 22:08 - 20 Oct 2025 22:08 #336785
by andypugh
Replied by andypugh on topic Feed per rev G95 way too fast
I think that the problem is with your fancy logic for converting the unidirectional spindle sensor into a directional one.
I am not sure that the logic will work as you hope, as the encoder won't change direction the instant that the motor direction reverses, it takes some time to reverse a spindle. (if you always stop it first, them it's probably fine).
You only need a bidirectional encoder on a lathe for rigid tapping, do you anticipate doing that?
It's probably easier to add an extra opto sensor. It just needs to be N + 1/4 further round the disc than the A sensor, using the same holes. (not N + 1/2, I have made that mistake...)
You mentioned that the index didn't seem to be working? Possibly a confusion about which channel it is on?Is it GPIO 14 or 8 ?
I am not sure that the logic will work as you hope, as the encoder won't change direction the instant that the motor direction reverses, it takes some time to reverse a spindle. (if you always stop it first, them it's probably fine).
You only need a bidirectional encoder on a lathe for rigid tapping, do you anticipate doing that?
It's probably easier to add an extra opto sensor. It just needs to be N + 1/4 further round the disc than the A sensor, using the same holes. (not N + 1/2, I have made that mistake...)
You mentioned that the index didn't seem to be working? Possibly a confusion about which channel it is on?
net spindle-index encoder.0.phase-Z <= hal_gpio.GPIO14-in
# Connect encoder index pulse (GPIO8).
Last edit: 20 Oct 2025 22:08 by andypugh.
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