Alternate coordinate systems not working

[aafuni]

If you choose G54 as the CS the machine probes the plate then sets the G54 CS to what the G53 CS is minus the plate thickness offset. If you home the machine to Zmax to have a safe parking position for the G53 location, you can't then set G54 with the touch plate.

[PyroAVR]

Does this happen with all coordinate systems, or only G54? I did intentionally write it such that the new CS would be set from the G53 CS, as I intended for the user to home the machine, touch off, and then set relative CS from that point. I am no machinist, and if this workflow is not the standard I can change it, but this is what I thought other platforms such as Mach 3 would do, although I am not sure.
On my tinyG machine, I can set G54, etc. from Zmax when homed by jogging the cutter to the touchplate and running the widget, but of course it cannot be set from the maximum to go any higher. The alternate CS will be initially zeroed at the point where the tool is moved to, because this allows the machine to home relative to the plate. What behavior were you expecting/what would be more optimal for the future?

I apologize for not getting back to this sooner. I just finished my semester a few days ago and am back home where I can test this.

[aafuni]

I think it is common practice, but am certainly no expert. The default TinyG post processor in Fusion360 puts a G53 Z0 at the end of the program.

My flow has been to set G53 to the machine coordinate system with the Z height at a "safe height" of Zmax, then from there set a work CS of G54 that is at the actual work piece (so this would be using the probe).

If I can keep G53 as the machine home rather than the part home, then I can have the machine return to its parking spot at the end of the job. The machine finishes the part, drives to clearance, then goes to G53.

[PyroAVR]

I did some research, and the widget works as it should in terms of the relative offsets. The coordinate systems G54-59.3 are set relative to G53, which are the machine absolute coordinates. These are what are set with G28.[1-3] when homing using limit switches, and the widget uses G28.3 to set the absolute coordinates with the touchplate when the user so desires.
Many CNC machines set some upper corner of their operating range as the origin. I know on my CNC, I configured it such that the upper left of the workspace is (0,0,0), and the Z axis works downwards for positive change in Z (which is backwards). However, when using the touchplate, the Z axis is reset such that Z0 maps to the top of the workpiece.

On your machine, you have options. It seems that Fusion is assuming you have your CNC configured similarly to how I have described it above, and that the origin is the safe height. If this is not the behavior you would like, you can change the last line to read "G53 Z " in your gcode.

If you are having troubles setting the Z offset with the way your machine is configured, you can issue G28.3 Xx Yy Zz to set the G53 to (x,y,z). This link may be of further assistance as well, specifically the section on G28, which is a special tinyG command.

I think that the widget should still work with your setup, you may have to issue G28.3 Z0 at your Zmax before running it if you encounter issues. Keep me updated on what happens, I may be able to make changes which would make this easier if it becomes a problem for many users.