Closed Loop Motor Setup

Toastinator

Can Closed Loop Steppers Only be Used on Cartesian/Delta Machines?

During Homing Sequence, Machine Moves X130 Y150 Same Time, When X Gets to Location, Z Starts Lifting and Is not Waiting for Y to Finish Getting to Location.

Phaedrux

@Toastinator said in Closed Loop Motor Setup:

Can Closed Loop Steppers Only be Used on Cartesian/Delta Machines?

I don't think that is the case.

Are you sure about the timings for the servos?

Toastinator

@Phaedrux

Thanks for the Reply, I Cannot be Sure about the Timing. The Manual does not go into Details about the timing.

I have Tried 0.5, up to 5.

How would I go about Finding the Correct Timing?

Phaedrux

I'm not really sure about that. Closed loop servos are well outside of my wheel house.

fcwilt

@Toastinator said in Closed Loop Motor Setup:

Can Closed Loop Steppers Only be Used on Cartesian/Delta Machines?

During Homing Sequence, Machine Moves X130 Y150 Same Time, When X Gets to Location, Z Starts Lifting and Is not Waiting for Y to Finish Getting to Location.

The drivers I have used have nothing like you PEND output indicating a move is in progress.

When the RRF firmware T values are set correctly the connected steppers behave like those which are driven directly by a Duet board driver.

Perhaps your driver needs changes made to the RRF firmware to handle the PEND output.

Just guessing about that though.

Good luck.

Frederick

alankilian

@Toastinator said in Closed Loop Motor Setup:

During Homing Sequence, Machine Moves X130 Y150 Same Time, When X Gets to Location, Z Starts Lifting and Is not Waiting for Y to Finish Getting to Location.

Could you post your homing files?

The Duet shouldn't even be able to tell if the motors are open or closed-loop, so I think it's something else.

Toastinator

@alankilian
Here is My Home All File. This Issue Only Happens When X and Y Movements are Done Together. Usually It Finishes X Movement, Still Moving Y and Begins Z Lift. During Prints there is a Continuous Layer Shift Indicating to me that Moves are not Finishing before starting the Next.

I have Started Playing with the Timing, and that does not seem to change anything other then if the Motors actually Move or not.

Im not sure how you would add somthing in the Config.g File to Wait for Move to complete before going to next move. monitored by Pend Connections on Each Motor.

G91                    								; relative positioning
G1 H2 Z5 F6000        								; lift Z relative to current position
G1 H1 X-370 Y-370 F1800 							; move quickly to X or Y endstop and stop there (first pass)
G1 H1 X-370            								; home X axis
G1 H1 Y-370             							; home Y axis
G1 X10 Y10 F6000        							; go back a few mm
G1 H1 X-370 F360        							; move slowly to X axis endstop once more (second pass)
G1 H1 Y-370             							; then move slowly to Y axis endstop
G90                     							; absolute positioning
G1 X121 Y207 F6000        							; go to bed probe point and home Z
G30                     							; home Z by probing the bed

dc42

@Toastinator said in Closed Loop Motor Setup:

During Prints there is a Continuous Layer Shift Indicating to me that Moves are not Finishing before starting the Next.

That usually means that one of the last two T values is too low for your driver. Low cost step servo drivers are often very slow to respond to direction changes. The manual you linked to did not specify the required timings, other than 200kHz maximum step pulse frequency.

Toastinator

@dc42 Thanks! I have Tried Numbers Varying up 500.

T5:5:50:250 And So On, How High is TOO High? 1000? 10000?

I Will keep Playing with Timing Keep Checking back

Edit: The Stupid Manual is not much of a manual. I saw the Step Pulse Frequency, But not Direction Setup time and Hold Times

dc42

@Toastinator said in Closed Loop Motor Setup:

@dc42 Thanks! I have Tried Numbers Varying up 500.

T5:5:50:250 And So On, How High is TOO High? 1000? 10000?

I Will keep Playing with Timing Keep Checking back

T2.5:2.5:50:50 should probably be high enough.

PS which Duet do you have, and how have you connected the drivers to it?

Toastinator

@dc42

Just Tried T2.5:2.5:50:50 Timing and It still Does the Same thing. Im wondering if this is a CoreXY Related Issue.

Im using a Duet 3 6HC, Duet 3 Expansion 3HC and 2 - Duet 3 Expansion 1XD Boards
The Motors are Connected by a "Differential Connection"

After Homing X and Y, X and Y Move Toward Center, When Y Finishes. X Continues Toward Center But now Z Starts Lifting Before getting to Center.

Phaedrux

Can you use M122 B# to check that your mainboard and all expansion boards are updated as well?

alankilian

I wonder what this means from the manual;

13 Pulse command filtering time
Unit: 50us
Range: 0~600
Default: 60

The larger the value, the smoother the motor runs and the noise,
but the position tracking lag time also increases.

50 microseconds times 60 is 3 milliseconds which is a LONG time.

The mention of "the position tracking lag time also increases" makes me think this thing might be accumulating a bunch of input pulses before starting to move the motor depending on whatever it's gains are set to.

But that would make these motors completely unsuitable for CNC or 3D printer applications, so I just don't know.

Toastinator

@Phaedrux

Yes, They all Report Back. I Had to Down Grade Firmware too 3.3Beta1 Because Using 3.3Beta2 Was Causing the Temperature of my Thermocouples to not read anymore.

@alankilian

Good Catch, If these Motors end up being Unusable. Would you or anyone else have a Suitable Option for Replacement? I Thought the Default 60 Meant 60us, Not 50us x 60.

alankilian

How about trying some square motion starting very slowly and getting faster and faster and make sure only one axis moves at a time?

I don't know the size of your machine or where the origin is, but something like this: (Made-up GCODE, you'll need to make real code)

G0 X0 Y0 Z10
G1 X300 F50
G1 Y300
G1 X0
G1 Y0
G1 X300 F100
G1 Y300
G1 X0
G1 Y0
G1 X300 F150
G1 Y300
G1 X0
G1 Y0
G1 X300 F200
G1 Y300
G1 X0
G1 Y0
G1 X300 F250
G1 Y300
G1 X0
G1 Y0

Toastinator

@alankilian

Ill give it a shot. Im also Checking into a way of Modifying that setting from 60 to somthing Much Lower. Should that be Lowered to 1? to = 50us

I don't see that as an option. A 3d Printer that can only Print square Objects! lol

alankilian

I'm interested in seeing if when you move very slowly that only one axis moves at time and (maybe) when yo move faster, it's not waiting for the move to complete and starting the next move due to "the position tracking lag..." mentioned above.

That would indicate it's more likely the drives and not a Duet firmware thing.

Toastinator

@alankilian Thanks for your help, I really appreciate it!

Alright, Heres what happened.
I Had to change the Speed because the original was moving at 0.5mm Per second. I did Pick Ridiculous Speed Numbers To see what would happen, and the Speed Remained CONSTANT the entire time suggesting the Speed is Controlled by the External Driver?

G90
G0 X0 Y0 Z10
G1 X300 F3000
G1 Y300
G1 X0
G1 Y0
G1 X300 F5000
G1 Y300
G1 X0
G1 Y0
G1 X300 F10000             <- Here is where it said the Print was Finished.
G1 Y300
G1 X0
G1 Y0
G1 X300 F15000
G1 Y300
G1 X0
G1 Y0
G1 X300 F20000
G1 Y300
G1 X0
G1 Y0

Edit: The External Driver Doesn't Fully Control the Speed, But Perhaps the Maximum Speed? When Requesting a Low Speed Like 50, it Moved at 0.5mm Per second. But at 3000, It was moving more like 50mm Per Second.

alankilian

This post is deleted!

Toastinator

I Just Got the Software to Modify the Settings Built in to the Closed Loop Stepper.

Will change the Motors back and Get back Tomorrow with the Findings

My First Attempt will change the Timing:

13 Pulse command filtering time
Unit: 50us
Range: 0~600
Default: 60 <- Will Change to 1 = 50us
 
The larger the value, the smoother the motor runs and the noise,
but the position tracking lag time also increases.