component thcud "Torch Height Control Up/Down Input";

to install open a terminal and cd to where the file is and use the following command

sudo comp --install thcud.comp

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.

Physical Connections typical
paraport.0.pin-12-in <= THC controller Plasma Up
paraport.0.pin-13-in <= THC controller Plasma Down
parport.0.pin-15-in  <= Plasma Torch Arc Ok Signal
parport.0.pin-16-out => Plasma Torch Start Arc Contacts

HAL Plasma Connections
thc.torch-up <= paraport.0.pin-12-in
thc.torch-down <= paraport.0.pin-13-in
motion.spindle-on => parport.0.pin-16-out (start the arc)
thc.arc-ok <= motion.digital-in-00 <= parport.0.pin-15-in (arc ok signal)

HAL Motion Connections
thc.requested-vel <= motion.requested-vel
thc.current-vel <= motion.current-vel

""";

author "John Thornton";

license "GPL";

option singleton yes;





// Input Pins
pin in bit torch_up "Connect to paraport.0.pin-12-in";//may need changed
pin in bit torch_down "Connect to paraport.0.pin-13-in";//may need changed
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 motion.spindle-on";
pin in bit arc_ok "Arc Ok from Plasma Torch";//may need changed
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";


// Parameters

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*(.8)); //.8 is velocity tolerance, change as needed
        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
    }
}




Items need added to HAL file

# Torch Height Control
loadrt thcud
addf thcud servo-thread

# position command and feedback
# hijack position command and feed through thc
net emcmot.02.pos-cmd thcud.z-pos-in <= axis.2.motor-pos-cmd
net thc-pos-cmd thcud.z-pos-out => hm2_[HOSTMOT2](BOARD).0.stepgen.02.position-cmd
net motor.02.pos-fb axis.2.motor-pos-fb <= thcud.z-fb-out


Place these two files here - PROGRAM_PREFIX = /home/tyler/linuxcnc/nc_files
or add this line to ini file and create the directory "m_code_files" at that location
[RS274NGC]
PARAMETER_FILE = linuxcnc.var
----> USER_M_PATH = /home/tyler/linuxcnc/m_code_files

Save below as "M101" and place in /home/tyler/linuxcnc/nc_files
#!/bin/bash
# file to activate THC - M101
halcmd setp thcud.enable True
exit 0

Save below as "M102" and place in /home/tyler/linuxcnc/nc_files
#!/bin/bash
# file to deactivate THC - M102
halcmd setp thcud.enable False
exit 0