Scara manual control

Fuzionline

@Fuzionline
Good afternoon! Are there any updates?

droftarts

@Fuzionline Ah, yes, M599 doesn't work on Duet 2 due to memory limitations.

Looking at your config.g, you seem to have your machine limits set to allow the Scara arm to go anywhere in a donut shape around the centre. Your M208 XY limits are +/- 1200mm, which is roughly the length of your proximal (765mm) and distal (475mm) arms, with a central no-go area of 450mm radius (ie 900mm diameter). Is this correct?

If you command it to go into any area within the 900mm diameter central area, I would think it should stop at the point it gets within 450mm of X0 Y0. If it continues to attempt to get there, I think that sounds like a bug. Can you confirm that's what you see?

Ian

Fuzionline

@droftarts

@droftarts said in Scara manual control:

Looking at your config.g, you seem to have your machine limits set to allow the Scara arm to go anywhere in a donut shape around the centre. Your M208 XY limits are +/- 1200mm, which is roughly the length of your proximal (765mm) and distal (475mm) arms, with a central no-go area of 450mm radius (ie 900mm diameter). Is this correct?

Regarding the M208 limits, everything is fine; when it reaches -1200/1200, it doesn't allow further movement.
However, there is an issue with the R value. I even increased it to R500, but it exceeds this value and continues until it reaches the limit defined by the distal angle, which is 150(endstop). If it continues to be commanded in that direction, it moves in the opposite direction and stops at the -151 distal angle.
It seems to me that the situation starts with it ignoring the value set in R.

@droftarts said in Scara manual control:

If you command it to go into any area within the 900mm diameter central area, I would think it should stop at the point it gets within 450mm of X0 Y0. If it continues to attempt to get there, I think that sounds like a bug. Can you confirm that's what you see?

No.Only stop when reach the 150 distal angle(420mm of X0 Y0 approximate).

droftarts

@Fuzionline said in Scara manual control:

No.Only stop when reach the 150 distal angle(420mm of X0 Y0 approximate).

I think that's the default. From 'Serial SCARA' tab of M669 https://docs.duet3d.com/en/User_manual/Reference/Gcodes#m669-set-kinematics-type-and-kinematics-parameters

Rnnn (optional, RRF 2.03 and later only) Minimum permitted printing radius from the proximal axis. If not specified, it will be calculated to be slightly larger than the distance between nozzle and proximal axis when the distal axis is homed.

So it does look like R is being ignored. I'll report it to @dc42 and see what he says.

Ian

Fuzionline

@droftarts
tks for your help

droftarts

@Fuzionline I've raised this as an issue on Github: https://github.com/Duet3D/RepRapFirmware/issues/1045

Ian

droftarts created this issue in Duet3D/RepRapFirmware

open [Bug]: Scara kinematics ignoring M669 R parameter in RRF 3.5.2 #1045

Fuzionline

@droftarts
Tks

Fuzionline

@Fuzionline
hello
Do you have news
tks

T3P3Tony

@Fuzionline did you test this with 3.6beta2 to see if its resolved or not?

Fuzionline

I updated to version 3.6.0 Release Candidate 1, but the M571 command doesn't work. I reverted to Release 3.5.4, and it's working. Thank you.
I have a Duet 2 wifi.

Fuzionline

@Fuzionline
I haven't had the opportunity to test 3.6 beta 2 yet to see if it resolved the issue with M669 R.

dc42

@Fuzionline said in Scara manual control:

I updated to version 3.6.0 Release Candidate 1, but the M571 command doesn't work. I reverted to Release 3.5.4, and it's working. Thank you.
I have a Duet 2 wifi.

Confirmed, M571 doesn't work in 3.6.0-rc.1 and 3.6 beta versions. It will be fixed in rc2.

Fuzionline

@dc42
Hello
Now with the rc2 it´s ok .
Another doubt

When I run a simulation and there is a movement that cannot be executed, the system correctly reports the error and shows the exact line in the G-code where the issue occurs — so far, so good.

However, sometimes the simulation finishes without detecting any errors, but when I start the actual print, I get errors in the console like:

Error: G1: intermediate position outside machine limits

These messages appear either in blue or red, but the printer keeps running without stopping.
Tks

dc42

@Fuzionline the reason for this is that when simulating on a Scara or other machine with nonlinear kinematics, RRF doesn't segment the moves and simulate the segments, but instead simulates the entire move. We tried simulating individual segments but found it was too slow. Unfortunately there are some situations in which out-of-bounds errors are only detected at the segment level; for example, if a move has reachable start and end coordinates but would bring the head too close to the proximal axis on the way between them.