PlanetCNC THC User manual

Torch height controller user manual
2020/08/26

Disclaimer
TORCH HEIGHT SENSOR DE ICE AND TORCH HEIGHT CONTROLLER ARE
PRO IDED TO YOU "AS IS," WITHOUT WARRANTY. THERE IS NO WARRANTY FOR
THE HEIGHT SENSOR AND HEIGHT CONTROLLER, EITHER EXPRESSED OR
IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT OF THIRD PARTY RIGHTS. THE ENTIRE RISK AS TO THE
QUALITY AND PERFORMANCE OF THE DE ICES IS WITH YOU. SHOULD THE
HEIGHT SENSOR OR HEIGHT CONTROLLER PRO E DEFECTI E, YOU ASSUME
THE COST OF ALL NECESSARY SER ICING, REPAIR OR CORRECTION.
IN NO E ENT SHALL THE AUTHOR BE LIABLE TO YOU FOR DAMAGES, INCLUDING
ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE TORCH SENSOR OR HEIGHT
CONTROLLER.
2

Introduction
1 Introduction
1.1 Overview
Plasma CNC cutting machine is one of the most commonly used types of CNC machine.
It’s used mostly for cutting Steel, aluminium and other conductive materials.
Like any other type of CNC machine, plasma machine has it own specifics. Machine
should be properly designed for such type of machining, considering slag, steel dust, high
temperatures, moisture, grease etc..
Plasma cutter is a great source of electromagnetic interference. So special care should be
taken into account when designing and wiring machine electronics.
Be sure to use shielded cables for motors, limit switches. External power supply for motion
controller is very recommended. Plasma cutters itself sometimes do not satisfy standards
of electromagnetic compatibility (EMC), so make sure that your plasma cutter is within
EMC regulations.
Heat emitted from plasma could deform workpiece material, usually metal sheet. In such
case plasma cutter would not cut at constant height which could result as a faulty
workpiece or could damage plasma cutter in the process. This is usually solved with THC
device. THC stands for Torch Height Control.
Torch height controller consists from torch height controller and torch height sensor device.
Torch height sensor device measures arc voltage. Bigger the distance between the plasma
torch and material higher the voltage and vice versa. So based on the measured voltage
value we can maintain constant height of plasma torch above the material.
Torch height sensor device is connected with torch height controller via optic cable. Torch
height controller then sends control signals (Up, Down, Arc OK) to motion controller which
then dynamically compensates Z axis and thus maintains constant cutting height.
3

Introduction
1.2 Features and specifications:
Torch height sensor device:
•Plasma arc voltage measurement up to 350
•Additional input for divided plasma voltage (1:50) up to 10
•Plasma voltage present signalization
•Full optical output isolation; transmitter and receiver connected over an optical fiber
cable
•Main AC power supply (110 AC-230 AC/50-60 Hz)
Torch height controller:
•Output signals: Arc Ok, Up and Down (normally-open solid-state relay outputs)
•Programmable reference and hysteresis voltage, delay time and anti-dive limit voltage
•Current plasma voltage presentation on LED display
•LED signalization of arc present, up and down signals
•Full optical input isolation; transmitter and receiver connected over an optical cable
•Test mode operation
•Wide power supply voltage range (6 - 36 )
4

Hardware
2 Hardware
2.1 Torch height controller terminal description
5

Hardware
2.2 Torch height sensor terminal description
6

Connection diagrams
3 onnection diagrams
3.1 High voltage source from plasma cutter
7

Connection diagrams
3.1.1.1
8

Connection diagrams
3.2 Divided voltage output source from plasma cutter
3.3 Torch height controller connection with Planet N controller
inputs
Please note that Down, Up, Arc OK signals can be connected to any input of PlanetCNC
controller since inputs function can be configured later in PlanetCNC TNG settings.
9

User Interface
4 User Interface
Parameters can be modified during operation and will immediately affect the output
signals! Device will automatically save the last settings.
During the plasma cutter’s operation, the current arc voltage is shown on the display.
If there are no arc voltage present, display shows - - -.
Reference voltage (Ref) can be set by pushing (left) or ꓥ(right) button. (During operation
the green (OK) led flashes when reference voltage is setting). User can set Ref from 45
to 265 . Factory setting 180 .
To enter a setup menu press and hold • (middle) button for one sec. The LED display will
start flashing then the setup menu will appear.
Select the parameter by pressing • button. Press / ꓥbutton to modify parameter’s value.
Sdt - Set delay time from 0.1 to 9.9 sec. Time between Arc OK signal appears and
generation of signals up and down is enabled. Factory setting 0.5 s.
HYS - Hysteresis from 2 to 32 (2 step). oltage frame around reference. If arc
voltage is higher than Ref + HYS/2 then down signal is generated. If voltage is lower than
Ref - HYS/2, up signal is generated (see the output signal example below). Factory setting
6 .
AdL - Ant-dive limit from 50 to 300 . Arc voltage that disables THC. If voltage goes
higher than Anti-dive limit all output signals go low. The parameter’s value must be set
higher than reference voltage. Factory setting 220 .
tSt - Test mode. Only available when no arc voltage present! Pressing or ꓥbutton
generate output signals. The display indicates direction.
To leave a setup menu, do not press any button for around 2 seconds.
In case of communication failure E-I is shown on the display. Please check the optical
cable is properly inserted on both sides and that the PlasmaSens sensor device is turned
on.
10

User Interface
11

Controller input configuration in PlanetCNC TNG software
5 ontroller input configuration in Planet N TNG software
User can configure controller inputs for THC under File/Settings/THC.
12

Controller input configuration in PlanetCNC TNG software
Axis:
User selects machine axis from drop down menu. Selected axis will be height
compensated.
Dec Pin:
Dec input pin number, located at INPUT header of controller. Select input pin number from
drop down menu.
When this input pin is active, machine will move/compensate in negative direction.
Down signal from torch height controller is connected to this input.
Inc Pin:
Inc input pin number, located at INPUT header of controller. Select input pin number from
drop down menu.
When this input pin is active, machine will move/compensate in positive direction.
Up signal from torch height controller is connected to this input.
OK Pin:
OK input pin number, located at INPUT header of controller. Select input pin number from
drop down menu.
If set, software waits until this input is active and only then begins with program
execution.
Arc OK signal from torch height controller is connected to this input.
Range Min/Max:
Low and high limit compensation travel.
Speed:
Speed of compensation moves. Units are mm/s or inch/s.
13

Controller input configuration in PlanetCNC TNG software
When torch height controller will activate its output, corresponding digital input of controller
should activate.
You can observe status of controller inputs via IO tab of PlanetCNC TNG state panel.
14

THC related g-codes
6 TH related g-codes
THC compensation can be enabled or disabled, as also additional gcode parameters can
be used so that machine behaviour will suit your plasma cutting requirements for better
cutting results.
M54 - Enable/Disable THC
Usage: M54 P <Q> <R> - P = zero for Off, otherwise On
- Q = speed limit
- R = constant speed
If speed limit is set then THC will not move Z axis if machine speed is below set speed.
If constant speed is enabled then THC will not move Z axis if machine is accelerating or
decelerating.
Example:
M54 P1 Q1000 R1 – enable THC for constant speeds (no acceleration) above 1000.
15

THC related g-codes
Table of ontents
1 Introduction.......................................................................................................................3
1.1 Overview....................................................................................................................3
1.2 Features and specifications:......................................................................................4
2 Hardware...........................................................................................................................5
2.1 Torch height controller terminal description...............................................................5
2.2 Torch height sensor terminal description...................................................................6
3 Connection diagrams........................................................................................................7
3.1 High voltage source from plasma cutter....................................................................7
3.2 Divided voltage output source from plasma cutter....................................................9
3.3 Torch height controller connection with PlanetCNC controller inputs.......................9
4 User Interface..................................................................................................................10
5 Controller input configuration in PlanetCNC TNG software............................................12
6 THC related g-codes.......................................................................................................15
16