Machinekit Documentation
HAL Component — THCUD
NAME
thcud — Torch Height Control Up/Down Input
SYNOPSIS
thcud
USAGE SYNOPSIS
loadrt thcud
DESCRIPTION
Torch Height Control This THC takes either an up or a down input from a THC
If enabled and torch is on and X + Y velocity is within tolerance of set speed allow the THC to offset the Z axis as needed to maintain voltage.
If enabled and torch is off and the Z axis is moving up remove any correction at a rate not to exceed the rate of movement of the Z axis.
If enabled and torch is off and there is no correction pass the Z position and feed back untouched.
If not enabled pass the Z position and feed back untouched.
Typical Physical Connections using a Parallel Port
Parallel Pin 12 ⇐ THC controller Plasma Up
Parallel Pin 13 ⇐ THC controller Plasma Down
Parallel Pin 15 ⇐ Plasma Torch Arc Ok Signal
Parallel Pin 16 ⇒ Plasma Torch Start Arc Contacts
HAL Plasma Connections
net torch-up thcud.torch-up ⇐ paraport.0.pin-12-in
net torch-down thcud.torch-down ⇐ paraport.0.pin-13-in
net torch-on motion.spindle-on ⇒ parport.0.pin-16-out (start the arc)
net are-ok thc.arc-ok ⇐ motion.digital-in-00 ⇐ parport.0.pin-15-in (arc ok signal)
HAL Motion Connections
net requested-vel thc.requested-vel ⇐ motion.requested-vel
net current-vel thc.current-vel ⇐ motion.current-vel
Pyvcp Connections In the xml file you need something like:
<pyvcp> <checkbutton> <text>"THC Enable"</text> <halpin>"thc-enable"</halpin> </checkbutton> </pyvcp>
Connect the Pyvcp pins in the postgui.hal file like this:
net thc-enable thcud.enable ⇐ pyvcp.thc-enable
FUNCTIONS
thcud.N (requires a floating-point thread)
PINS
torch-up bit in - Connect to an input pin
torch-down bit in - Connect to input pin
current-vel float in - Connect to motion.current-vel
requested-vel float in - Connect to motion.requested-vel
torch-on bit in - Connect to motion.spindle-on
arc-ok bit in - Arc Ok from Plasma Torch
enable bit in - Enable the THC, if not enabled Z position is passed through
z-pos-in float in - Z Motor Position Command in from axis.n.motor-pos-cmd
z-pos-out float out - Z Motor Position Command Out
z-fb-out float out - Z Position Feedback to Axis
cur-offset float out - The Current Offset
vel-status bit out - When the THC thinks we are at requested speed
removing-offset bit out - Pin for testing
PARAMETERS
velocity-tol float rw - The deviation percent from planned velocity
correction-vel float rw - The Velocity to move Z to correct
AUTHOR
John Thornton
LICENCE
GPLv2 or greater