Scara support ?

dc42

There are pics of my SCARA printer at https://miscsolutions.wordpress.com/2017/08/09/testing-the-robotdigg-scara-arm-3d-printer/. It's a very cheap printer - Duet electronics are too good for it! But it's good enough for me to use it to test the SCARA support.

dc42

My SCARA printer is now working properly. SCARA fixes are in the 1.19+4 bugfix test version - see separate thread.

frafa

Hello

IR sensor received
I removed end-stop from the Z
I connected "IR Sensor" to the end-stop of the Z
I can not run correctly
Can you give me an example for config.g and homeall.g? (hooming Z and auto-levelling bed.g on Scara ?)

I put M558 P5 but I have error if i use G30 on homeall.g

[c]G28
Attempt to move the head of a Delta or SCARA printer before homing the towers
Error: Z probe already triggered at start of probing move
Error: Z probe already triggered at start of probing move
Error: Homing failed[/c]

I get to operate without G30 in homeall.g in the meantime …

[[language]]
;homeall.g 
... Home x/y ok ...
G91                ; relative movement
G1 S1 Z-400 F250    ; ensure head is clear of the bed
G1 S2 Z6          ; move Z by 6 mm
G1 S1 Z-10 F100    ; move proximal joint slowly to the endstop switch again
G90                ; absolute movement

dc42

The IR sensor should be connected as a Z probe, not an endstop switch. See https://duet3d.com/wiki/Connecting_a_Z_probe. You can keep the existing homing switch if you like and just use the Z probe to do mesh levelling or just to get a more accurate Z=0 position immediately before printing.

frafa

ok

Other problem impossible to move X / Y with G1 in scara if Z is not homing

; homeall.g
; called to home all axes
; File homeall.g
;G91 ; relative movement
;G1 Z4 F100 ; ensure head is clear of the bed

; Home proximal joint
G91
G1 S1 X-200 F2000 ; move proximal joint clockwise by up to 200 degrees until the endstop switch is triggered
G1 S2 X5 ; move proximal joint anticlockwise by 10 degrees
G1 S1 X-20 F300 ; move proximal joint slowly to the endstop switch again
G90 ; absolute movement
;G1 S2 X0 F2000 ; move proximal joint to centre of range

; Home distal joint
G91 ; relative movement
G1 S1 Y200 F2000 ; move distal joint clockwise by up to 200 degrees until the endstop switch is triggered
G1 S2 Y-5 ; move distal joint anticlockwise by 10 degrees
G1 S1 Y20 F300 ; move distal joint slowly to the endstop switch again
G90 ; absolute movement
;ko
G90 ; absolute movement
G1 X150 Y150 F2000 ; move distal joint to centre of range

; Home Z
G91 ; relative movement
G1 S1 Z-400 F250 ; ensure head is clear of the bed
G1 S2 Z6 ; move Z by 6 mm
G1 S1 Z-10 F100 ; move proximal joint slowly to the endstop switch again
G90 ; absolute movement

;ok
G90 ; absolute movement
G1 X150 Y150 F2000 ; move distal joint to centre of range

dc42

In my homeall.g file, after homing the proximal and distal joints I use G90 then G0 S2 Xxxx Yyyy Ffff, where xxx and yyy are the angles that I want the proximal and distal joints to take up prior to Z homing. This gets round the issue of moves to XYZ coordinates not being allowed until all axes have been homed.

frafa

ok ==> G0 S2 Xxxx Yyyy Ffff

It is not conceivable for the futur to RFF support connect IR Sensor to End-Stop Z ?
Would it be cleaner at the wiring level ?
(I do not want to keep Mechanical Z End-Stop)

dc42

No. The IR sensor produces a 4-level analogue output. This is so that the firmware can slow down the probing move when the trigger point is approaching.

You will need to change your homeall.g file, also homez.g if you are using one, to use a G30 probing move instead of a G1 S1 move. See https://duet3d.com/wiki/Configuring_RepRapFirmware_for_a_Cartesian_printer#Homing_Z.

frafa

ok i change connect tomorrow …

Where connect "out" (3-pin IR Sense on duet-wifi)

dc42

Not on the expansion connector at all. Use the Z probe connector and see the link i posted earlier (6 posts back).

frafa

ok
out IR Sense (3-Pin) on ==> Z PROBE IN ?

dc42

Yes. Leave the Mod pin on the Z probe connector unconnected.

frafa

Hello
Sorry to solicit you again …

Z End-Stop removed
And "IR Sense" connect on "Z probe connector"

my config.g (End-stop only)
; Endstops
M574 X1 S0 ; Define (P) active low microswitches
M574 y2 S0 ; Define (D) active high microswitches
M574 Z0 S0 ; Define (Z) active low and unused microswitches
M558 P2 X0 Y0 Z1 H5 F120 T2000 ; Set Z probe type to modulated, the axes for which it is used and the probe + travel speeds
G31 P500 X30 Y30 Z2.5 ; Set Z probe trigger value, offset and trigger height
M557 X15:285 Y15:285 S20 ; Define mesh grid

my homeall.g (Z Only)
…
G90 ; absolute movement
G30 ; Single Z-Probe

Z does not stop where is my error ?

frafa

Hummmm….
modified M558/G31/M574 Z

[[language]]
; Endstops
M574 X1 S0 ; Define (P) active low microswitches
M574 y2 S0 ; Define (D) active high microswitches
M574 Z0 S1 ; Define (Z) active low and unused microswitches
;Z probe
M558 P1 I1 X0 Y0 Z1
G31 Z2.5 P500

[[language]]
16:04:09
Attempt to move the head of a Delta or SCARA printer before homing the towers
16:04:05
G28
Error: Z probe already triggered at start of probing move
Attempt to move the head of a Delta or SCARA printer before homing the towers
Error: Z probe already triggered at start of probing move
Error: Homing failed

frafa

Found ! ok
M558 P1 I0 X0 Y0 Z1

dc42

The default for M558 is I0. Your mistake was to use P2, because P1 is correct as described at https://duet3d.com/wiki/Connecting_a_Z_probe#Mini_differential_IR_sensor_by_dc42

frafa

It all starts to work really well
Homing, auto-leveling …

Another question: p
How the heightmap.csv file is used
In my gcode after G28 I add a G29 S1 to recharge it?

dc42

G29 S0 (or G29 with no parameters) generates a height map, activates it, and also saves it. The default filename is heightmap.csv. You can load and activate a height map that you have previously generated using G29 S1.

I've just released test firmware 1.19+3 which includes a code speedup of some of the SCARA calculations. I've also reduced the default segments/sec from 200 to 100, because 200 turned out to be too many - although that was before I implemented part of the code speedup.

frafa

A small facelift for my 3D printer
It remains to find a place to the electronics, surely at the top of the mat?
Again thanks to you for your reactivity, I will talk about the Duet all around me
https://youtu.be/yfZkDReH0pI

dc42

Looking good!

I guess there is no obvious place to put the electronics for a SCARA printer. On my SCARA printer almost the entire Z axis rotates, so the Duet is mounted on the Z axis to avoid a lot of rotating cables (just like the original electronics that was supplied with the printer). I haven't worked out a good place to put a Panel Due yet - having a touch screen that rotates is not a good option! I don't have a bed for my SCARA printer - I print on blue tape stuck to the desk. You do have a bed so you could put the Duet below that, but you would still need to find somewhere to put the touch screen.

If you are happy with the way the Duet is running your SCARA printer, perhaps you would like to write a post about your machine at http://forums.reprap.org/list.php?185.

In your initial post in this thread, you implied that you were using Smoothieware to run your printer. I'm a little surprised that you decided to risk purchasing a Duet for it, even though homing wasn't implemented in RepRapFirmware at that time. Can you explain your reasons?

Let me know if there is anything else you feel is missing from the SCARA support. I'm still a SCARA novice and I probably have a lot to learn.