Mesa 7i39 + 5i20 + Pittman ELCOM ST BLDC
- karl1
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I setup the following combination of components:
Pittman ELCOM ST BLDC Motor - uses 34 pattern for hall effect sensor commutation. 4 poles.
24VDC power supply
USDigital Encoder model E5S-1024-315-IG - no index, no compliments for A or B signal.
two Mesa 7i39-LV - about 2 years old, but never got to work before recent LinuxCNC update. These are on connectors P2 and P3 of the 5i20.
Mesa 5i20 card - works well; I also have a 7i33 that I've used to test other motors and amplifier combination. The 7i33 is not wire into this setup.
using LinuxCNC 2.5
Used PNCconf, and with some tweeking, I have movement from the above setup.
Problem is there is no feedback from the encoder in LinuxCNC, and I'm sure I'm missing the needed HAL components for this. When running the Axis demo g-code, seems to run away, but does reverse directions. When I turn motor shaft, no feedback; display never changes x axis values.
I only have one axis, the X-Axis, wired for now. Motor is not coupled with anything.
Could someone who has worked with both Hall Sensors and Encoder Feedback post a HAL and INI file that they have working? I'm glad I have movement, and really anxious to tie the x-axis into LinuxCNC, before I wire up the remaining motors.
I've attached my HAL and INI files for this setup.
Thanks!
Karl
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- BigJohnT
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John
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- karl1
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- PCW
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- karl1
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I am embarrassed to say that the wiring was correct, but the lack of any signal was purely a rookie mistake.
I literally have a hundred of these motors in my scrap bin - all next to new. I happen to grab one for this testing that I had removed the encoder's optical transmissive module; this happened about a year ago when I was troubleshooting an encoder problem. The electrical connector snapped and latched into the housing. I never bothered to check "under the cover", and when I finally removed it to replace what I thought was a blown module, I was shocked to see it missing. Funny that I should meet it half way with a signal.

I just need to get the rotation of the motor feedback to match the proper direction in LinuxCNC - throws a joint 0 error when commanding a positive motion and feeds back a negative. Anyone have a quick solution?
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- andypugh
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Reverse almost any of the scales. Or pset the dir pin of bldc, or even find the other working Hall pattern or swap any two motor power leads or exchange A and B on the encoder or....I just need to get the rotation of the motor feedback to match the proper direction in LinuxCNC - throws a joint 0 error when commanding a positive motion and feeds back a negative. Anyone have a quick solution?
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- karl1
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Studied the following link:
www.linuxcnc.org/docview/2.5/html/man/man9/bldc.9.html
Thanks all! I will post my final set up with pictures. Stay tuned.
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- andypugh
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Ihttp://www.linuxcnc.org/docview/2.5/html/man/man9/bldc.9.html
I do intend writing something rather more informative at some point.
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