Unexpected behaviour of expression { } in command parameters.

wackyfrog

Hi, David!

It seems that not more that one expression can be used when it is necessary to specify several values, for instance:

M581 P{var.myVar1}:{var.myVar2}:{var.myVar3} ...

My test g-code:

global x_axis_endstop_pin = 6
global y_axis_left_endstop_pin = 7
global y_axis_right_endstop_pin = 8
global z_axis_endstop_pin = 9

echo {global.x_axis_endstop_pin}
echo {global.y_axis_left_endstop_pin}
echo {global.y_axis_right_endstop_pin}
echo {global.z_axis_endstop_pin}

; Emergency stop trigger on endstops hits
M581 T8 R0 S1 P{global.x_axis_endstop_pin}:{global.y_axis_left_endstop_pin}:{global.y_axis_right_endstop_pin}:{global.z_axis_endstop_pin}

Only the first pin triggers when its state changes. The rest 3 specified pins does not cause the trigger.

Am I use wrong syntax or it is a bug ?

Echoed values are correct, additionally I have checked them in the object viewer.

And all 4 pins work correctly only when I specify them manually, like this:

M581 T8 R0 S1 P6:7:8:9

Board: Duet 2 WiFi (2WiFi)
Firmware: RepRapFirmware for Duet 2 WiFi/Ethernet 3.4.0beta5 (2021-10-12)

Thank you very much!

dc42

@adegtiar I have updated https://duet3d.dozuki.com/Wiki/GCode_Meta_Commands#Section_Use_of_expressions_within_GCode_commands to show the correct syntax.

wackyfrog

@dc42 said in Unexpected behaviour of expression { } in command parameters.:

@adegtiar I have updated https://duet3d.dozuki.com/Wiki/GCode_Meta_Commands#Section_Use_of_expressions_within_GCode_commands to show the correct syntax.

I have tried that syntax, but got an error:

M581 T9 R0 S1 P{global.x_axis_endstop_pin, global.y_axis_left_endstop_pin, global.y_axis_right_endstop_pin, global.z_axis_endstop_pin}

Error: M581: expected '}'

jay_s_uk

@adegtiar there should be + in between , not a ,

wackyfrog

@jay_s_uk said in Unexpected behaviour of expression { } in command parameters.:

@adegtiar there should be + in between , not a ,

Thank you! It works

wackyfrog

Returning to the question, I found that the solution still does not work.

Tested on Firmware: RepRapFirmware for Duet 2 WiFi/Ethernet 3.4.0 (2022-03-15)

Operator '+' just summarizes pins values and as result I have one pin number 30 instead of 4 pins (6:7:8:9)

G-CODE to reproduce

; Variables
global x_axis_endstop_pin = 6
global y_axis_left_endstop_pin = 7
global y_axis_right_endstop_pin = 8
global z_axis_endstop_pin = 9


; remove all pins from trigger
M581 T9 P-1

; check the trigger configuration
M581 T9
Result: Trigger 9 is not configured

; setup new pins
M581 T9 R0 S1 P{global.x_axis_endstop_pin + global.y_axis_left_endstop_pin + global.y_axis_right_endstop_pin + global.z_axis_endstop_pin}

;  check what we have
M581 T9
Result: Trigger 9 fires on a rising edge of endstops/inputs 30

dc42

@wackyfrog the M581 P parameter is a single string so you need to concatenate the various parts using ^. Try this:

M581 T9 R0 S1 P{global.x_axis_endstop_pin ^ "+" ^ global.y_axis_left_endstop_pin ^ "+" ^ global.y_axis_right_endstop_pin ^ "+" ^ global.z_axis_endstop_pin}

wackyfrog

@dc42 I've got the error:

M581 T9 R0 S1 P{global.x_axis_endstop_pin ^ "+" ^ global.y_axis_left_endstop_pin ^ "+" ^ global.y_axis_right_endstop_pin ^ "+" ^ global.z_axis_endstop_pin}
Error: M581: expected integer value

wackyfrog

As a workaround, I'm currently using the code below, but I would like to figure out how to correctly pass multiple values using variables in such parameters.

M581 T9 P-1
M581 T9 R0 S1 P{global.x_axis_endstop_pin}
M581 T9 R0 S1 P{global.y_axis_left_endstop_pin}
M581 T9 R0 S1 P{global.y_axis_right_endstop_pin}
M581 T9 R0 S1 P{global.z_axis_endstop_pin}
M581 T9

Result: Trigger 9 fires on a rising edge of endstops/inputs 6 7 8 9

dc42

@wackyfrog I'm sorry, I made a mistake. In RRF 3.4 the M581 P parameter is a list of pin numbers that you created using M950 with the J parameter. So this command from your earlier post should work under firmware 3.4:

M581 T9 R0 S1 P{global.x_axis_endstop_pin, global.y_axis_left_endstop_pin, global.y_axis_right_endstop_pin, global.z_axis_endstop_pin}

But I've just tested it, and I get the same error that you reported. I am investigating why.

dc42

@wackyfrog I found and fixed the problem. The fix will be in the 3.4.1 release.

wackyfrog

@dc42 Thanks, David!