PRICECNC AVHC10 User manual

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CNC Plasma Torch Height Controller
Installation and Operation Manual
Model: AVHC10 Revision: 1.2

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SAFETY NOTICE
WHEN THIS DEVICE IS IN OPERATION, VOLTAGES
HAZARDOUS TO HEALTH AND HUMAN LIFE ARE
PRESENT INSIDE THE ISOLATION MODULE.
This device should only be connected by a qualified and authorized person.
Improper connection can cause serious injury or death. Prior to installation and
operation, carefully read the entire manual and be absolutely sure that you fully
understand and are able to make the sole decision to determine if you are capable of
a safe and proper installation. Remember that inside the Isolation Module, voltages
hazardous to health and life may be present.
There must be no physical contact with any electrical connections while this device
or any connected device is powered. Do not operate this product with wet hands, wet
gloves, or any wet clothing. Before turning the unit on, secure the safety of others,
and read and understand all instructions. If you have any questions or concerns, do
not continue.
Warning: Provide adequate protection for all risks associated with plasma cutting.
For more detailed information of the risk associated with plasma cutting, refer to your
plasma cutter's owner manual.
This device must be earthed/grounded in accordance with this installation guide,
earthing of non-electrified conductive parts (including device housings) is an
essential part of electrical safety.
Touching non-insulated and non-grounded elements can be fatal. Provide a safe
place for your device. After installation, securely protect against any physical contact
between the terminals on the Isolation Module and any person(s).
It is strictly prohibited to perform any repairs or modifications to this product,
performing either one of these actions could lead to serious injury or death to
yourself and/or others.
Terms of Use: By proceeding with the installation and use of this product, you fully
understand and agree that PRICECNC and their distributors are not liable for any
incident or event resulting in direct loss, indirect loss, injury to self or others, damage
to property, or loss or damage of any kind and that the end user assumes all risks. If
you do not agree to these terms in their entirety, proceed no further, and return this
product for a full refund.
If you have any questions or are unsure about anything stated in this manual, please
contact a PRICECNC dealer or service centre for assistance.

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Contents
Introduction......................................................................................................................... 4
1 Installation........................................................................................................................ 5
1.1 High Frequency Plasma Cutter Interference ................................................................ 5
1.2 Earthing....................................................................................................................... 6
1.3 Raw Arc Measuring Point Connections........................................................................ 6
1.4 50:1 Measuring Point Connections .............................................................................. 6
1.5 Floating Z Axis (not included) ...................................................................................... 7
1.6 Anti-Dive...................................................................................................................... 7
1.7 AVHC10 Installation Wiring Diagram ........................................................................... 8
1.8 Wiring Definitions......................................................................................................... 9
2 AVHC10 Operation ......................................................................................................... 10
2.1 Display List ................................................................................................................ 11
3 Appendix ........................................................................................................................ 14
3.1 Setting up the AVHC10 in Mach 3......................................................................... 14
3.2 Setting up the AVHC10 in SheetCAM........................................................................ 16
Introduction
When using a CNC Plasma cutting table, good cut quality can only be achieved by
maintaining a consistent distance between the cutting torch and the material being cut. This
can be difficult to achieve as heat from the cutting process can warp the material being cut
or the material that is being cut may not be level or flat. To overcome these problems during
cutting, the cutting torch needs to be raised and lowered to compensate for changes in the
height of the sheet.
The PRICECNC Arc Voltage Height Controller measures the voltage between the plasma
torch and the material being cut, this is known as the ‘Arc Voltage’. As the distance between
the torch and the material changes during a cut, the voltage also changes. The greater the
distance, the higher the voltage and the smaller the distance the lower the voltage. By
measuring the changes in the Arc Voltage, the AVHC10 can continuously adjust the arc
length for optimum cutting performance.
Different materials types and thicknesses require different height controller setting. For
convenience, up to 30 different material or thickness settings can be saved on the AVCH10.

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1 Installation
The PRICECNC Arc Voltage Height Controller has two main components. One is called the
‘User Interface’ and the other is called the ‘Isolation Module’. Both of these units need to be
connected to each other. The Isolation Module also connects to the plasma cutter and the
user interface also connects to a power supply and the signal inputs and outputs on the
breakout board.
In this installation example, we show how to install the PRICECNC AVHC10 on to a Plasma
CNC table with the following properties:
Design Software SheetCam
Work Software
MACH 3
Breakout Board 5-axis with 1 relay output and 5 inputs
PC to Breakout Board Interface
LPT
Parallel Printer Port
CNC Machine Custom/Homemade/DIY 3 Axis CNC Table with
Floating Z axis
Mechanical Drive Stepper Motors
Plasma Cutter R-Tech Plasma50CNC
1.1 High Frequency Plasma Cutter Interference
Some value plasma cutters use a high frequency, high voltage striking arc to strike across
the air gap between the plasma cutter electrode and the work piece. This striking arc can
generate massive electromagnetic fields which can interfere with surrounding electronics
including CNC motors, drive units, breakout board and Computers. This electromagnetic
field comes from the cables that connect the plasma cutter electrode to the plasma cutting
machine. Cables that are connected to this circuit can also spread interference. The
PRICECNC Arc Voltage Height Controller is designed to keep this interference away from
the CNC control circuitry by utilising a completely electrically isolated measuring circuit in the
Isolation Module. The Isolation Module is also supplied and fitted with a shielded cable that
provides the User interface with a clean signal for accurate measurement.

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1.2 Earthing
To prevent the above mentioned High Frequency interference from becoming an issue on
your CNC plasma cutting equipment, proper earthing/grounding must be fitted using at least
16mm
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(AWG 5) multi strand cable. In a typical 3 axis CNC plasma cutting setup, the
following components should be earthed direct to the star point:
•Arc Voltage Height Controller aluminium case.
•Fixed portion of table.
•Gantry
•Buggy
•Z axis travel plate
•Stepper/Servo motor control box
•Plasma Cutter case
The star point is a point where the earth wires from all of these individual items meet, this is
then connected to the earth electrode. The alternative to a star point earthing system is a
daisy chain earth system. This is not recommended as it is not as effective at preventing
interference.
1.3 Raw Arc Measuring Point Connections
For best results, the cables that connect the Isolation Module to the plasma cutter should be
protected from the effects of a bad connection on the circuit that carries the plasma current.
Sometimes rust or dirt on the work sheet can cause a poor clamp connection which can
create a voltage difference between the clamp and the work piece which would affect the
measured voltage used for controlling torch height. For best results, the black connection on
the Isolation Module should be connected to the work piece by a separate small clamp.
A poor connection on the torch cable can cause the same issue, for best results, the
connection from the Blue plug on the Isolation Module should be connected to the plasma
torch as close to the tip as safely possible. Preferably, where the flexible air/current hose
connects to the torch.
1.4 50:1 Measuring Point Connections
The 50:1 measuring circuit is designed to work with the 50:1 voltage divider output on a
Hypertherm Powermax 45 Plasma Cutter and other Plasma cutters that use the same
resistor network to create the 50:1 voltage. The Hypertherm Powermax 45 plasma cutter
uses 100,000 and 2,000 ohm resistors in series to produce the a 50:1 voltage across the
2,000 ohm resistor. The PRICECNC AVCH10 is calibrated for use with 50:1 voltage dividers
with these particular resistances. Other resistor values will work but the accuracy of the
measured voltage may be affected. The overall circuit resistance of the voltage divider
should not exceed 120,000 ohms.

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1.5 Floating Z Axis (not included)
For best plasma cutting results, the height at which each cut in a job starts should be
measured by a floating Z axis. The floating Z axis operates a switch which activates the
Digitize/Probe input in Mach3 when the torch descends into the work piece. When this
method is used with the correct G-code (G31), the Z axis Digital Read Out (DRO) will be
reset to zero at the start of each cut. This compensates for uneven sheet height and
improves the cut quality.
1.6 Anti-Dive
A reduced feed rate is often used when cutting small holes or tight angles, this reduced feed
rate increases the arc voltage which will cause the AVHC10 to lower the torch into the work
piece. To prevent the torch diving into the work piece when a reduced feed rate is used,
Torch Height Control should be deactivated during the reduced feed rate. One way to
deactivate Torch Height Control is to use an anti-dive Macro in Mach 3. Unfortunately Mach
3 pauses the operation of the CNC machine momentarily while it executes the macro which
may result in poor cut quality (dings/notches).
To overcome this, the PRICECNC AVHC10 can take in a signal that blocks outgoing Raise
and Lower commands. Using the correct cut rules in SheetCAM, the Post Processor will
write G-code that includes a command to turn on and off a signal output on the breakout
board. This signal is received by the AVHC10, blocking the raise and lower commands. This
method is simple to install on most Breakout boards and prevents the CNC machine from
needing a Macro to turn Torch Height Control on and off.
When anti-dive is activated, both blue LEDs will light up.
1.7 Mounting Holes
There are two threaded holes on the rear of the
AVHC10 that can be used to mount the unit
onto your CNC machine or control console.

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1.8 AVHC10 Installation Wiring Diagram

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1.9 Wiring Definitions
AVHC10
Wire Pairs Polarity Function Min. Value Max. Value Unit
Red Positive Supplies power to the AVHC10 8 35 V
Black Negative
White Positive Measures the signal from the
Isolation Module
Black Negative
Yellow Positive Receives Anti-Dive Signal from
Mach 3 via Breakout Board 2 50 V
Black Negative
Green Either Sends Arc OK Signal to
Mach 3 via Breakout Board
50 V
Black Either 100 mA
Blue Either Sends Torch Up Signal to
Mach 3 via Breakout Board
50 V
Black Either 100 mA
Brown
Either
Sends Torch Down Signal to
Mach 3 via Breakout Board
50
V
Black Either 100 mA
Isolation Module
Wire Pairs Polarity Function Max. Value Unit
White Positive Sends Isolated and reduced
signal to the AVHC10 5 V
Black Negative
4mm Plug Polarity Function Max. Value Unit
Blue Negative* Connects to Plasma Electrode -300 continuous*
(HV starting Arc OK) V
Black Positive* Connect to Plasma Return clamp
50:1 Plug Polarity Function Max. Value Unit
Green See
Label Connects to 50:1 voltage divider 6 (HV starting through
100k Resistor OK) V
* Most Plasma Torch Electrodes operate at Negative Voltages

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2 AVHC10 Operation
The AVHC10 is always ready to work when powered on, minimising the need to interact with
the device. The way the AVHC10 operates can be set by the user by using the Jog Wheel to
navigate through the simple menu structure.
The recommended sequence of events for Plasma Cutting using the AVHC10 is:
1. Prepare G-code that uses a floating Z axis to find a new Z axis zero at the start of
each cut and also activates Anti-Dive on certain types of cut operations like tight
radius cuts and corners.
2. Run the cut job.
3. The Torch moves over the first pierce point.
4. The Torch lowers until the floating Z axis switch is triggered by the torch touching the
material to be cut. (G31).
5. The Z axis position is reset to Zero minus the switch offset (G92).
6. The Torch is raised to the pierce height and Plasma is turned on.
7. After the (G-code) pierce delay, the torch is lowered to the cut height.
8. The torch moves along the cut while the AVHC10 monitors the Arc Voltage and
issues raise and lower commands to Mach 3 via the Breakout Board.
9. The torch comes to a tight radius bend during the cut which contains an M11P2 (Turn
off THC) command which turns on the output signal that activates the AVHC10 Anti-
LCD Display
Display Number
Jog Wheel
Earthing Screw
2 Mounting
Screws on
Rear
Signal
Indicator
LEDs