Possible bug (RRF3.5.1): M208 throws error when used with array

[NeoDue]

In order to make axis limits tool-dependent (see here), i wanted to define the X and U limits on my IDEX printer as follows:

; config.g
if !exists(global.X_Limit)
    global X_Limit = {-175.5,151}       ; X limits
if !exists(global.U_Limit)
    global U_Limit = {-151,175.5}       ; U limits

;[...]

M208 X{global.X_Limit[0]}:{global.X_Limit[1]} Y-101:101 Z0:209 U{global.U_Limit[0]}:{global.U_Limit[1]}

That resulted in the error "M208: U axis maximum must be greater than minimum".

The same happens if I define only the U or the X values to shorten the command.

If I use the old separate notation however...

M208 S0 X{global.X_Limit[1]} Y101 Z209 U{global.U_Limit[1]}
M208 S1 X{global.X_Limit[0]} Y-101 Z0 U{global.U_Limit[0]}

...it works as it should, except that the variables are not replaced by their values in the console output.

Can anyone confirm this behaviour?

[dc42]

@NeoDue There has been a change to the way that expressions are used as parameters with array type in GCode commands. Now the entire parameter must be either a colon-separated list of literal values, or an expression of array type. Try this:

M208 X{global.X_Limit[0], global.X_Limit[1]} Y-101:101 Z0:209 U{global.U_Limit[0], global.U_Limit[1]}

[NeoDue]

@dc42 Thanks, that one works as intended

[dc42]

@NeoDue I have now added this change to the upgrade notes at https://github.com/Duet3D/RepRapFirmware/wiki/Changelog-RRF-3.x#reprapfirmware-351-stable-changes-since-346.