Troubleshooting RPi + mesa 7i76e + omc steppers
06 May 2022 10:44 #242118
by Jeremie
Troubleshooting RPi + mesa 7i76e + omc steppers was created by Jeremie
Hello everyone,
I'm trying to build a 3 axis CNC based on a killerbee mechanical kit. It is the first time I'm building such a thing. I've decided to really on linuxcnc in order to learn as much as possible on all topics from electrical to electronics and how to build an autonomus machine in general that could help me to tackle more ambitious wookworking projects.
Actual setup
The problem
I'm struggling at troubleshooting what's wrong with my setup. To summarize what i've done so far
1. create a basic config for the mesa with all values by default in order to make the X motor moves
2. use the X axis tune for find the right values to prevent the drivers to to itself in safety mode (it blinks 7 times)
Based on the driver documentation blinking 7 times means any of this situation
I've got the impression that I miss something big but I can't tell what. Do you have any idea on how to troubleshoot this?
I'm trying to build a 3 axis CNC based on a killerbee mechanical kit. It is the first time I'm building such a thing. I've decided to really on linuxcnc in order to learn as much as possible on all topics from electrical to electronics and how to build an autonomus machine in general that could help me to tackle more ambitious wookworking projects.
Actual setup
- RPi 4 that runs linuxcnc (i've followed this documentation )
- A mesa 7i76e
- 4 drivers OMC stepper online CL57T
- 4 nema 23 motors OMC stepper online 23hs45-4204D
The problem
I'm struggling at troubleshooting what's wrong with my setup. To summarize what i've done so far
1. create a basic config for the mesa with all values by default in order to make the X motor moves
2. use the X axis tune for find the right values to prevent the drivers to to itself in safety mode (it blinks 7 times)
Based on the driver documentation blinking 7 times means any of this situation
- The acceleration time setting is too small, increase the value of appropriately;
- Motor torque is not enough or motor speed is too high;
- Motor wiring error, check wiring
I've got the impression that I miss something big but I can't tell what. Do you have any idea on how to troubleshoot this?
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06 May 2022 10:46 #242119
by Jeremie
www.youtube.com/shorts/4NNmbMMivDk please find in real what's happening.
Thanks in advance for your help!
Replied by Jeremie on topic Troubleshooting RPi + mesa 7i76e + omc steppers
www.youtube.com/shorts/4NNmbMMivDk please find in real what's happening.
Thanks in advance for your help!
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06 May 2022 12:17 #242129
by andypugh
Replied by andypugh on topic Troubleshooting RPi + mesa 7i76e + omc steppers
Can you attach the HAL and INI files?
It seems like the acceleration and/or velocity settings are too high, and the motor is immediately stalling.
But it is also possible that the motor is wired incorrectly.
**** Power off the drives before disconnecting the motor *********
Check, with a multimeter, that A+ and A- are connected in the motor, and the same for B+ to B- (assuming a 4-wire stepper)
If it is a 6 or 8-wire stepper then there is even more scope to get things wrong. I have had 8 wire steppers where the wire colours did not match the datasheet.
It seems like the acceleration and/or velocity settings are too high, and the motor is immediately stalling.
But it is also possible that the motor is wired incorrectly.
**** Power off the drives before disconnecting the motor *********
Check, with a multimeter, that A+ and A- are connected in the motor, and the same for B+ to B- (assuming a 4-wire stepper)
If it is a 6 or 8-wire stepper then there is even more scope to get things wrong. I have had 8 wire steppers where the wire colours did not match the datasheet.
The following user(s) said Thank You: Jeremie
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06 May 2022 13:08 #242134
by spumco
The following user(s) said Thank You: Jeremie
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06 May 2022 14:39 #242144
by itsme
Replied by itsme on topic Troubleshooting RPi + mesa 7i76e + omc steppers
Wrong Encoder or Motor wiring...
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06 May 2022 15:07 - 06 May 2022 15:09 #242147
by Jeremie
Replied by Jeremie on topic Troubleshooting RPi + mesa 7i76e + omc steppers
First of all, thanks everyone for your reactivity this is much appreciated
Indeed, it was a wiring problem of the encoder, the pinout was wrong like Spumco suggested it in another topic.
I thought I could trust OMC but in the end nothing could replace an exhaustive continuity testing of all motors.

Indeed, it was a wiring problem of the encoder, the pinout was wrong like Spumco suggested it in another topic.
I thought I could trust OMC but in the end nothing could replace an exhaustive continuity testing of all motors.
Last edit: 06 May 2022 15:09 by Jeremie.
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