1HCL Closed Loop - layer shifts - Timing?

T3P3Tony

@gruna-studio which, the 1HCL expansion board? How was it broken? We will probably want that back for investigation.

A Former User

Duet3 3HC expansion board has a small burninig on it. I will send a picture. I haven´t used it before.
But crazy issue for a burned board.

Just a last quick question.
How to calculate the steps per mm in closed loop? same way like open loop but no microsteps?
I have a gt2 with 20 teeth = 40 mm
200 steps per revolution / 40 = 5 ----

I have 100steps/ mm (which is crazy high) but the models are printed only 20 per cent to big. How can that be?

thanks
Richard

A Former User

@gruna-studio

T3P3Tony

@gruna-studio thanks for confirming that - can you email warranty@duet3d.com to arrange a replacement referencing this thread.

I think the issue with microsteps on your setup is because the scaling provided by M350 is still having an impact. 100 steps/mm does not sound right. I expect you have M350 set to 16 (which is the default where microstepping applies) which would be a steps/mm setting of 80 in your setup. (16*5 = 80). If you would prefer to work in full steps then set M350 to 1 and M92 to 5.

edited to add an update:

The microstep setting should be high enough to use the full encoder CPR. e.g. if the encoder is 1000 PPR (so 4000 CPR) and the full steps/rev is 200, then the microstepping needs to be at least 4000/200 = 20 to make use of the full resolution of the encoder.

So in that case I would use M350 X32, and M92 X160 (adjust for the other axis you have with 1HCL.).

T3P3Tony

@gruna-studio I have also updated the documentation page to make this clear:
https://docs.duet3d.com/en/Duet3D_hardware/Duet_3_family/Duet_3_Expansion_1HCL#microstepping

A Former User

@t3p3tony
ok great information!!
It´s working great, now. It´s kind of crazy this closed loop system.
thanks for updating the documentation.

cheers
richard

T3P3Tony

@t3p3tony said in 1HCL Closed Loop - layer shifts - Timing?:

@gruna-studio thanks for confirming that - can you email warranty@duet3d.com to arrange a replacement referencing this thread.

did you see this regarding the damaged expansion board?

A Former User

@t3p3tony
Yes. Sry
I'll do it
Cheers

A Former User

Are there some new information about tuning 2 motors an the same axis?
Would be very nice
Cheers
Richard

dc42

@gruna-studio not yet. Do you mean the basic closed loop tuning that you need to do on every power up, or PID tuning?

A Former User

@dc42
In this case the v31 manoeuvre. But for PID tuning it would be also helpful.
Cheers