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 ⇐ parport.0.pin-12-in
net torch-down thcud.torch-down ⇐ parport.0.pin-13-in
net torch-on spindle.0.on ⇒ parport.0.pin-16-out (start the arc)
net arc-ok thcud.arc-ok ⇐ motion.digital-in-00 ⇐ parport.0.pin-15-in (arc ok signal)
HAL Motion Connections
net requested-vel thcud.requested-vel ⇐ motion.requested-vel
net current-vel thcud.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.-
PINS
- thcud.torch-up bit in
-
Connect to an input pin
- thcud.torch-down bit in
-
Connect to input pin
- thcud.current-vel float in
-
Connect to motion.current-vel
- thcud.requested-vel float in
-
Connect to motion.requested-vel
- thcud.torch-on bit in
-
Connect to spindle.N.on
- thcud.arc-ok bit in
-
Arc Ok from Plasma Torch
- thcud.enable bit in
-
Enable the THC, if not enabled Z position is passed through
- thcud.z-pos-in float in
-
Z Motor Position Command in from axis.n.motor-pos-cmd
- thcud.z-pos-out float out
-
Z Motor Position Command Out
- thcud.z-fb-out float out
-
Z Position Feedback to Axis
- thcud.cur-offset float out
-
The Current Offset
- thcud.vel-status bit out
-
When the THC thinks we are at requested speed
- thcud.removing-offset bit out
-
Pin for testing
- thcud.correction-vel float in
-
The Velocity to move Z to correct
PARAMETERS
- thcud.velocity-tol float rw
-
The deviation percent from planned velocity
AUTHOR
John Thornton
LICENSE
GPLv2 or greater