Having severe limit switch issues

I am having real problems getting my limit switches to work at the same time as my touch plate.

My setup is an XCarve that was originally a Shapeoko2, upgraded to the latest model except I am using the original TinyG board. The only non standard thing on my setup is that I have an extended Y axis giving a build area of 715mm x 2200mm (28×86 inches) and the Z axis has been somewhat extended.

I am using chilipeppr as the UI. I reflashed the board with the latest version yesterday (.95)

The situation is that I am unable to get the machine to behave correctly. The errant behaviors include:

With $st=0 (Normally Open)

Homing cycle works on X and Y axis. The Touch plate works exactly once. Attempts to recalibrate result in the machine locking up completely. All commands result in {“ey”:0} being returned. Alternatively, the machine just tries to drive the tool right into the bed and keep going.

Touch plate seems to be calibrating to the wrong value, cutter is a couple of mm above the bed and can’t be persuaded to go lower.

With $st=1 (Normally Closed)

Homing cycle does not work on X or Y. The machine drives into the limit switch as normal but does not back off as it should.

Currently, I have the limit switches set up as follows:

xmin 1 (homing)
ymin 1 (homing)
zmax 2 (limit)
zmin,xmax,ymax 0 (disabled)

I have tried different settings on zmax. Setting zmax to 1 seemed to cause the spindle to attempt to home off the upper limit switch.

One thing that seriously worries me is that chilipeppr seems to be using G28.2 X0 Y0 Z0 to home the machine. Which obviously isn’t the right thing to do with a touch off plate.

There seems to be a pervasive confusion between the use of the switches for limit and homing. When I hit machine home, I want it to go to z=max, x=0, y=0 in that order. Calibrating to a touch off plate is a totally different operation in my view.

Any ideas?