component thcud "Torch Height Control Up/Down Input";
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
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Parallel Pin 12 <= THC controller Plasma Up
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Parallel Pin 13 <= THC controller Plasma Down
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Parallel Pin 15 <= Plasma Torch Arc Ok Signal
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Parallel Pin 16 => Plasma Torch Start Arc Contacts
HAL Plasma Connections
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net torch-up thcud.torch-up <= parport.0.pin-12-in
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net torch-down thcud.torch-down <= parport.0.pin-13-in
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net torch-on spindle.0.on => parport.0.pin-16-out (start the arc)
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net arc-ok thcud.arc-ok <= motion.digital-in-00 <= parport.0.pin-15-in (arc ok signal)
HAL Motion Connections
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net requested-vel thcud.requested-vel <= motion.requested-vel
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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
""";
author "John Thornton";
license "GPLv2 or greater";
option singleton yes;
// Input Pins
pin in bit torch_up "Connect to an input pin";
pin in bit torch_down "Connect to input pin";
pin in float current_vel "Connect to motion.current-vel";
pin in float requested_vel "Connect to motion.requested-vel";
pin in bit torch_on "Connect to spindle.N.on";
pin in bit arc_ok "Arc Ok from Plasma Torch";
pin in bit enable "Enable the THC, if not enabled Z position is passed through";
pin in float z_pos_in "Z Motor Position Command in from axis.n.motor-pos-cmd";
// Output Pins
pin out float z_pos_out "Z Motor Position Command Out";
pin out float z_fb_out "Z Position Feedback to Axis";
pin out float cur_offset "The Current Offset";
pin out bit vel_status "When the THC thinks we are at requested speed";
pin out bit removing_offset "Pin for testing";
// Parameters
param rw float velocity_tol "The deviation percent from planned velocity";
param rw float correction_vel "The Velocity to move Z to correct";
// Global Variables
variable float offset;
variable float last_z_in;
function _;
;;
#include "rtapi_math.h"
FUNCTION(_) {
if(enable){
float min_velocity = requested_vel -(requested_vel*(velocity_tol*0.01));
if(current_vel > 0 && current_vel >= min_velocity){vel_status = 1;}
else {vel_status =0;}
if(torch_on && arc_ok && vel_status){ // allow correction
if(torch_down){
offset -= correction_vel;
}
if(torch_up){
offset += correction_vel;
}
last_z_in = 0;
}
if(!torch_on){ // remove any offset
float z_diff;
z_diff = z_pos_in - last_z_in;
if(z_diff > 0 && offset != 0){ // torch is moving up
removing_offset = 1;
if(offset > 0){ // positive offset
if(offset > z_diff){ // remove some
offset -= z_diff;
}
else {offset = 0;}
}
if(offset < 0){ // negative offset
if(offset < z_diff){ // remove some
offset += z_diff;
}
else {offset = 0;}
}
}
else {removing_offset = 0;}
last_z_in = z_pos_in;
}
z_pos_out = z_pos_in + offset;
z_fb_out = z_pos_in; // keep axis motor position fb from being confused
}
if(!enable){
z_pos_out = z_pos_in;
z_fb_out = z_pos_in; // keep axis motor position fb from being confused
}
}