This is a Vismach simulator config intended for testing out tool-changer configurations
The Vismach model combined with the sim_vmc.hal file features three axes
with home and limit switches, a carousel with both gray-code and pulse/index outputs, 
a locking bar and a power drawbar. 
There are two alternative configs, one demonstrating gray-code carousel coding and the other demonstrating
pulse/index.
Note that the carousel component also supports straight-binary and individual sensors. 

The "virtual" VMC is created by the sim_vmc.hal file and defines the following signals
that my be used in the other HAL files

Axis positions
x-pos
y-pos
z-pos

Axis limits
x-pos-lim
x-neg-lim
y-pos-lim
y-neg-llm
z-pos-lim
z-neg-lim

Simulated Spindle
spindle-cmd - set spindle speed in rpm, negative for reverse
spindle-pos - the simulated spindle position (revs)
spindle-vel - the simulated spindle speed out

Toolchanger arm
arm-act - actuate the arm
arm-in - arm in limit switch
arm-out - arm out limit switch

Carousel lock
car-lock - activate the lock
car-locked
car-unlocked - limit switches

Drawbar
tool-release
tool-released
tool-locked

Carousel
car-fwd rotate clockwise
car-rev rotate anticlockwise
bit0
bit1
bit2
bit3
bit4 - Gray-coded carousel position