ASI BAC2000 Bacdoor programming help

[zachattack2881]

@Georgia088, are you trying to control these separately because of a failed vcm in your mower? I just picked up a cub cadet mower from 2020 with a dead vcm. I got the contactors to close and was able to manually command each motor controller thru the back door software. Trying to get the mower working again without buying a 500 dollar vcm. Just curious if this is what you ended up doing

 

[Georgia088]

@Georgia088, are you trying to control these separately because of a failed vcm in your mower? I just picked up a cub cadet mower from 2020 with a dead vcm. I got the contactors to close and was able to manually command each motor controller thru the back door software. Trying to get the mower working again without buying a 500 dollar vcm. Just curious if this is what you ended up doing

Yes, and I do have it working... sorta. I didn't want to spend the $500 either. It took a lot of work though and I'm still not happy with the performance.

 

[zachattack2881]

Yes, and I do have it working... sorta. I didn't want to spend the $500 either. It took a lot of work though and I'm still not happy with the performance.

Good to know. I have some ideas on things to try so I'll be sure to post anything meaningful here. I might try to just use the can bus like the vcm did so I hopefully don't have to alter wiring or configs of the controller.

 

[Georgia088]

Please post. I haven't looked at any of mine for a while, but it is about grass cutting time again. I have actually used it a few times this season and it does work, but I need to figure out how to program the motor for better performance. I do not think my blade speed is high enough and I also don't think the drive motor is configured correctly. It will stall and I have to turn off and back on. This happened several times in my last cut. Keep me posted. If I can be any help, I'll be glad to. Thanks.

 

[zachattack2881]

Please post. I haven't looked at any of mine for a while, but it is about grass cutting time again. I have actually used it a few times this season and it does work, but I need to figure out how to program the motor for better performance. I do not think my blade speed is high enough and I also don't think the drive motor is configured correctly. It will stall and I have to turn off and back on. This happened several times in my last cut. Keep me posted. If I can be any help, I'll be glad to. Thanks.

So i replaced my VCM with a microcontroller and a couple switches. I got the microcontroller to talk with the motor controllers over CAN and was able to switch on the mower blades (i have 2 controllers for blades), which just links to a toggle switch (when the microcontroller sees the switch flipped, it commands the blades to 100% throttle). I did get the drive motor to spin aswell over the CAN bus. I used the stock throttle sensor wires, used analog read on the microcontroller, and mapped that to a throttle % sent over CAN. This is all with the wheels up in the air. I havent made any changes to wiring besides the custom connectors I made for where the VCM use to be.

The problem ive run into is when i put the mower on the ground and try to drive, the motor makes all sorts of racket and i dont move, and usually the controller faults for instantaneous current (or something like that). I see you had played with the tuning parameters and got something working, i just dont get why the defaults the controller already had arent working.

I dont belive the VCM is doing anything special. Looking at the controller configs, the only parameters coming over CAN bus is the Motor Current limit percent, Braking Current Limit percent, Motor State (0=off, 1=idle (not sure what idle is), 2=RUN), and throttle percent. That makes me confident the VCM isnt "reconfiguring" the tuning parameters or anything.

Hopefully I can get my hands on a known good VCM and monitor the CAN bus to figure this out. If not ill keep tinkering and see if I can get it working

Would you mind sending me the .xml config of the baseline(before changes) and the one you have now that seems to work a bit? I havent gotten mine to move under its own power yet so id atleast like to get that.

 

[zachattack2881]

Small update. The motor stuttering is just when you try to start from a stop. Giving it a push and hitting the throttle works wonders and it seems to drive great. I ended up mowing the whole yard like that. I just need to figure out the starting from a stop thing.

I did probe all the Hall sensor pins and verified they are all working as the trouble starting is usually a symptom of a faulty hall sensor/sensorless operation. I'll continue to investigate.

Also I'll post all the files to build your own VCM standin on GitHub once the project reaches a good point

 

[Georgia088]

Small update. The motor stuttering is just when you try to start from a stop. Giving it a push and hitting the throttle works wonders and it seems to drive great. I ended up mowing the whole yard like that. I just need to figure out the starting from a stop thing.

I did probe all the Hall sensor pins and verified they are all working as the trouble starting is usually a symptom of a faulty hall sensor/sensorless operation. I'll continue to investigate.

Also I'll post all the files to build your own VCM standin on GitHub once the project reaches a good point

Hey. sorry just seeing this, yes I can get you the files. They are on my other computer. It still doesn't work correctly. It jerks at start and sometimes faults still. Like you described, once it starts, it runs good, but to start from a stand still is not right. I will be glad to send the file I am using over though.. Maybe you can correct it... What model mower do you have?

 

[zachattack2881]

Hey. sorry just seeing this, yes I can get you the files. They are on my other computer. It still doesn't work correctly. It jerks at start and sometimes faults still. Like you described, once it starts, it runs good, but to start from a stand still is not right. I will be glad to send the file I am using over though.. Maybe you can correct it... What model mower do you have?

I have the cub cadet lt42e from 2020. I think I got it all figured out. Ended up being some throttle ramp tuning. Can start perfectly from a dead stop and even tow my double jetski trailer through my yard.

 

[Georgia088]

I have the cub cadet lt42e from 2020. I think I got it all figured out. Ended up being some throttle ramp tuning. Can start perfectly from a dead stop and even tow my double jetski trailer through my yard.

Awesome! Do you mind sharing your configuration files? Mine still jerks at startup.

Thanks!

 

[zachattack2881]

Awesome! Do you mind sharing your configuration files? Mine still jerks at startup.

Thanks!

Yeah I'll grab the config files from my controllers. I didn't change anything on the controllers tho. I implemented a replacement vcm that communicated over CAN bus just like the normal vcm. Initially I did have stuttering at startup too but the fix was just too adjust the throttle curve so it wasn't linear from 0 to 100%. If that is something that can be programmed into the BAC controller since you modified yours to have the throttle go directly to the controller then I would think that it would do the same thing