ontime AVC118 User manual

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AVC118
ARC VOLTATGE CONTROLLER
Instruction Manual
Revision 2.0A
Mar. 2012
SHENZHEN ONTIME TECHNOLOGY CO.LTD

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Introduction
The AVC-118 is a voltage sensing torch height control system
that is designed for the CNC plasma cutting machines.
During cutting process, the cutting current always keep
constant, and the cutting arc voltage will be changed with the
height of torch. When the distance between the torch nozzle
and work piece increases, the arc voltage increases, on the
opposite, the arc voltage will decrease. AVC118 plasma arc
voltage torch height controller will detect the voltage changes,
then control the distance between cutting torch and work piece
via the lifting motor in order to keep the arc voltage within a
given range, so that the height of cutting torch is kept within a
corresponding range.
Specifications
Work power: DC24V±10%, 3-5A.
The total power of the DC supply must be 10W bigger than the
power of the torch lifting motor.
Lifting motor: DC24V motor within the power of 60W.
Drive Mode: PWM (pulse width modulation).
Working Temperature: -10℃- 60℃

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IHS (Initial Height Setup) mode:
Inductive proximity switch mode.
Torch tip ohmic contact mode, only be suited for the
plasma power which has less HF and HV interferences
and working in dry cutting condition.
Arc voltage divider ratio: 1:100.
Accuracy: ±1V to ±5V adjustable.
Outline: 240mm/210mm/60mm(L/W/H).

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Pictures

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System connection
AVC118 controller system connection
AVC118 Controller
CNC
SYSTEM
WORK PIECES
PLASMA
ARC VOLT
MOTOR
Torch
Lifter
SHIELD
L
I
M
I
T
PRO SW
GROUND
START

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Connectors
Terminals outline
J1：Connect to CNC controller.
J2：Connect to DC24V power supply, lifting motor and limit
switches.
J3：Connect to the proximity switch and plasma start switch.
J4：Connect to the arc voltage sampling terminals.
J5：Connect to the torch shield cap signal terminal.
GND：Connect to the system ground. The grounding cable
should be at least 4mm2.
5 1 1 7
9 6 1 5
GND

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TERMINALS DEFINITION
NAME TERMINAL SIGNAL FUNCTION
J1
1 AUTO CNC AUTO THC Enable
2 UP CNC Torch Up Signal
3 DOWN CNC Torch Down Signal
4 START CUT CNC Start Cutting Signal
5 NC
6 MOTION Motion Enable to CNC
7 NC
8 COM GND of Control Signals
9 NC
J2
1 UP_LMT Upper Limit Switch
2 DOWN_LMT Lower Limit Switch
3 COM GND of Control Signals
4 MOTOR_1 Motor Terminal 1
5 MOTOR_2 Motor Terminal 2
6 DC24V(+) Power Supply DC24V(+)
7 DC24V(-) Power Supply DC24V(-)
J3
1 PRO_VCC_12V+ Power of the Proximity
Switch :+12V
2 PRO_SW_SIGNAL Proximity Switch signal in
3 PRO_GND_0V
GND of the Proximity Switch
Power: 0V
4 PLASMA_START1 Plasma Start Switch Term.1
5 PLASMA_START2 Plasma Start Switch Term.2

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J4：Arc voltage input.
Through this lock terminal, Connect the WORK terminal
inside the controller to the positive terminal of plasma
power, and connect the E-TRODE terminal to the
negative terminal of the plasma power.
AVC118 has been integrated an isolated arc voltage
divider, the divided ratio is 1:100. The arc voltage sense
wires should be at least 0.9 mm squared twisted pair
wire, rated 600V or greater. When connecting arc
voltage sense wires to the controller, please check the
arc voltage polarity carefully to ensure correct
connection, otherwise serious damage may occur.
J5：SHIELD CAP.
Through this lock terminal, Connect the shield cap lead
line (as the Ohmic IHS sensing signal) to the SHELD
terminal.

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J4 ,J5 connection illustration
J5：
SHIELD: CAP SHIELD
LEAD LINE
J4：
E_TRODE: ARC VOLT-
WORK: ARC VOLT+

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CNC INTERFACE
J1: connected to the CNC control system.
Terminal description:
J1-1: AUTO
Auto height control enable signal from CNC to AVC118
controller. Default definition: HIGH level signal enable
auto control, LOW level signal disable auto control. This
definition can be reversed by demand when placing order.
J1-2: UP
Torch UP signal from the CNC. Active level: LOW.
J1-3: DOWN
Torch DOWN signal from the CNC. Active level: LOW.
J1-4: START CUT
Start cutting cycle signal from the CNC, this signal must be
maintained during the entire plasma cutting cycle. Active
level: LOW.
J1-5: NC
J1-6: MOTION
Motion enable signal output to the CNC system. This signal
is issued after the plasma torch ignition and the pierce
process has been completed. This signal indicates that the

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CNC should begin the cutting motion. In case of serious
error occurred during the plasma cut, this signal will be
reset to high level. Active level: LOW.
Please refer to the MOTION signal interface circuit
illustration.
J1-7: NC
J1-8: CNC_COM
This is the common ground terminal of all above signals.
MOTION signal interface

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LIFTER MOTOR AND LIMIT SWITCH
Lifter motor：
DC shunt motor, 24V DC, power within 60W.
Connected terminal: J2-5 and J2-6, if the torch up and down
direction is not corresponding to the controller, please
exchange the lead wires of the lifter motor.
Limit switch：
J2-1: Connect to the terminal of normal open contact of the
upper limit switch.
J2-2: Connect to the terminal of normal open contact of the
lower limit switch.
J2-3: Connect to the terminals of common contact of the upper
and lower limit switches.
PLASMA START
Terminal: J3-5 and J3-5. Relay contact output, 10A/250V.
Connect to the start arc terminal of the plasma power source.

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Proximity switch IHS mode
Terminal: J3-1: +12V output, supply for proximity switch.
J3-2: proximity switch signal input.
J3-3: 0V, ground.
Proximity switch type:
NPN, normal open, sense distance 2mm.
If there is a short wire connected between terminal J3-2 and
j3-3, you should remove it before connecting the proximity
switch.
When more than one proximity switch used, the user can
design a proper interface board or refer to the simple series
connection illustration.
Simple series connection illustration.
DC24V+
DC24V-
SIGNAL

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Shield cap IHS mode
Terminal: J5.
Through this lock terminal, Connect the shield cap lead wire
(as the Ohmic IHS sensing signal) to the SHELD CAP terminal.
The Ohmic IHS sense wire should be at least 0.5 mm squared,
rated 1000V or greater.
Shield cap IHS illustration
SHIELD
CAP

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Operation mode
The AVC118 will work in auto mode after power on. This
means that the controller will take the responsibility to monitor
the arc voltage and modify the torch height correctly during
plasma cut. In case of needed, you can Press the
AUTO/MANU key to enter into manual operation mode, and it
is your responsibility to maintain the torch height correctly.
Operational keys
MEMU --- Menu key
ENTR --- Enter key.
UP --- Move the lifter upward while standby.
Increase the value while parameter setup.
Increase the given arc voltage while cutting.
Select previous items while menu operation.
DOWN --- Move the lifter downward while standby.
Decrease the value while parameter setup.
Decrease the given arc voltage while cutting.
Select next items while menu operation.

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Arc voltage setup
Press the MENU key once while standby, the controller will
enter into parameter setup interface, then press UP or DOWN
arrow key to select menu items, press the ENTR (enter) key to
setup working arc voltage when it displays Arc_Volt
information. Now the current arc voltage value will be
displayed on the LCD display and the cursor blinks, after that,
press the UP or DOWN arrow key to increase or decrease the
value of working arc voltage. Holding the UP or DOWN key for
about 2 seconds to increase or decrease the value
automatically and faster. Press ENTR key to confirm and exit
to menu item select interface. After all working parameters
have been setup properly, press the MENU key to return to
standby status while menu item select interface.
IHS time setup
The unit of the initial height setup (IHS) time is 10ms
(millisecond).
The procedure of the IHS time setup is the same as above.
Caution: if the IHS time is setup to zero, the controller will not
execute initial height setup procedure and will start arc directly.

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You have to setup the initial torch height manually when start
arc.
Pierce time setup
The unit of the pierce time is 0.1s (second).
The procedure of the pierce time setup is the same as
above.
Caution: if the pierce time is setup to zero, the controller
will not execute pierce procedure. The CNC controller should
take the responsibility of pierce procedure control.
IHS Test
Press the MENU key once while standby, the controller will
enter into parameter setup interface, then press UP or DOWN
arrow key to select menu items, press the ENTR (enter) key to
enter into IHS test interface when it displays Ihs_Test
information. Now the controller will ask you to press the ENTR
key again to confirm and start the IHS test procedure. Now
you can press the MENU key to exit or the ENTR key to start
the IHS test procedure, you can also press the UP or DOWN
key to enter into IHS_TIME setup procedure to modify the IHS

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time. During the IHS test procedure you can press the ENTR
key to stop the procedure manually. After the IHS test
procedure, press the MENU key to return to standby status
while menu item select interface.
Arc Test
Press the ARC_TEST key while standby, the controller will
enter into arc test interface, the controller will ask you to press
the ENTR key to confirm and start the arc test procedure. You
can press the ARC_TEST key to exit or the ENTR key to start
the arc test procedure. During the arc test procedure you can
press the ENTR key to stop the procedure manually. After the
arc test procedure, press the ARC_TEST key to return to
standby status.
Inner parameters configuration
Caution: All inner parameters should not need to be changed
after the controller had been installed and debugged properly
by the CNC cutting machine manufactory. They are only
provided to a trained engineer to optimize the technical
performance.

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Press the MENU key once while standby, the controller will
enter into parameter setup interface, then press the UP and
DOWN arrow key at the same time for about 3 seconds, then
release the key, the controller will enter into inner parameters
setup interface.
Press UP or DOWN key to select the inner parameter
which you want to modify, press ENTR key once to edit
current parameter, and then press the UP or DOWN arrow key
to modify current parameter value, press ENTR key again to
return. Press the MENU key to exit to standby status after all
inner parameters have been setup properly.
MAX_PWM：The maximum PWM value of the lifting motor.
This parameter defines the maximum speed of torch
lifting motor.
Range:60-120，default：120.
MIN_PWM：The minimum PWM value of the lifting motor.
This parameter defines the minimum speed of torch
lifting motor.
Range:10-120，default：30.
IhsUPPWM: The IHS upward PWM value of the lifting

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motor.
This parameter defines the upward speed of torch lifting
motor during initial height setup procedure.
Range: MIN_PWM-MAX_PWM，default：30.
IhsDN PWM：The IHS downward PWM value of the lifting
motor.
This parameter defines the downward speed of torch
lifting motor during initial height setup procedure.
Range: MIN_PWM-MAX_PWM，default：90.
U&D_ PWM：The upward and downward PWM value of the
lifting motor.
This parameter defines the speed of torch lifting motor
during manual torch height control.
Range: MIN_PWM-MAX_PWM，default：120.
ARC_TOLE：Arc voltage toleration range.
This parameter defines the maximum allowable positive
deviation from the given arc voltage. An arc voltage
deviation bigger than this value means that the torch is
cutting across a kerf, and the controller will disable
auto height control temporally to avoid the cutting torch
diving into the workpiece.