Sensorless homing with dual Y motors.

wdenker

I have a custom build I am working on that is utilizing dual Y motors on a duet 3 and expansion board and toolboard. I have all of the firmware up to date on each of the boards. I am trying to get my sensorless homing resolved and found out that every other time I home with Y it only uses one Y motor and swaps to the other Y motor every other time. I have uploaded my config.g and my homey.g I also have video showing it doing this. Any ideas?

homey.g config.g

Phaedrux

Can you post your video?

Firmware version?

Have you done any of the sensitivity tuning required for stall detection?

https://docs.duet3d.com/en/User_manual/Connecting_hardware/Sensors_stall_detection

wdenker

@Phaedrux I have done all of this. Literally one motor spins on the first home sequence and then the other motor spins on the second sequence. So I am only getting one motor at a time on homing. Also to note I have modified my config.g a little and it seems to have made things a little more consistant. config (3).g working on uploading the video to drive now since I can't directly here because of the size.

wdenker

@Phaedrux https://drive.google.com/file/d/1OJUGAJQfAjk0c5YrzlNQWeJ3KOkPR1mq/view?usp=drivesdk

Phaedrux

M913 Y95 ; reduce motor current to 45% to prevent belts slipping

You're not actually dropping the current all that much. The comment says 45%, but the actual command is 95.

You may also want to look into M201.1 to reduce acceleration for homing.

Your config also has M584 defined twice.

Phaedrux

Firmware version?

wdenker

@Phaedrux said in Sensorless homing with dual Y motors.:

M201.1

3.4.5 and M201.1 is that new? because 201 doesn't work like it used to. I used to use M201 and M205 so now your saying I need to call M201.1 I also got both axis working by specifying my second Y as A for it's axis and then hiding it and reclassifying it in my home file at the end.

Phaedrux

@wdenker said in Sensorless homing with dual Y motors.:

because 201 doesn't work like it used to

What do you mean by this?

https://docs.duet3d.com/en/User_manual/Reference/Gcodes#m2011-set-reduced-acceleration-for-special-move-types

M201.1 is new and optional. It's the same as setting M201 manually in certain cases.

@wdenker said in Sensorless homing with dual Y motors.:

I also got both axis working by specifying my second Y as A for it's axis and then hiding it and reclassifying it in my home file at the end.

Splitting the axis is another way to go.

wdenker

@Phaedrux Ya I created a new A axis and I used to could use M201 but I guess they implemented 201.1 now for homing. I was able to get this resolved by creating the new A axis and using M201.1 to slow it down on homing. Thanks!

dc42

@wdenker it should be possible to home dual Y axis motors without splitting the motors into separate axes, but you may need to use M201.1 to reduce the acceleration in order to prevent one of the motors stalling immediately.

wdenker

@dc42 I was only able to get them to work together on a home by creating a second axis and hiding that axis and homing them together.