Lincoln Electric POWER MIG SVM165-A - Manual (Page 40)

WELD CONTROL BOARD
The Weld Control Board performs the primary interfac-
ing functions to establish and maintain output control of
the Power MIG 350MP machine. The function genera-
tor and weld files reside within the Weld Control Board
hardware and software. Digital command signals and
feedback information from other machine components
are received and processed at the Weld Control Board.
Software within the Weld Control Board processes the
command and feedback information and sends the
appropriate pulse width modulation (PWM) signals to
the Chopper Assembly IGBT. (See Pulse Width
Modulation in this section.) In this manner, a digitally
controlled high-speed welding waveform is created.
In addition, the Weld Control Board monitors the
Chopper thermostat and the Main Transformer sec-
ondary winding thermostat. In the event of a fault con-
dition, the Weld Control Board will activate the thermal
light and will disable or reduce the machine output.
THEORY OF OPERATION
E-6 E-6
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POWER MIG 350MP
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
FIGURE E.6 – WELD CONTROL BOARD
IGBT
+
LINE
SWITCH
RECONNECT
PANEL
MAIN
TRANSFORMER
RELAY
SPOOL
GUN
BOARD
FEEDER
BOARD MSP
BOARD ENCODER
BOARD DISPLAY
BOARD
RS232
CONNECTOR WELD CONTROL BOARD
SPOOL GUN
PUSH-PULL
SWITCH
WIRE DRIVE
MOTOR
OUTPUT
RECTIFIER CHOPPER
ASSEMBLY
OUTPUT
CHOKE
CURRENT
TRANSDUCER
GUN
POS
OUTPUT
TERMINAL
NEG
OUTPUT
TERMINAL
POWER
BOARD
DIODE CONTROL
RECTIFIER
FAN
MOTOR
FOOT AMPTROL OR REMOTE (6-PIN AMPHENOL)
SPOOL GUN OR PUSH-PULL GUN (7-PIN AMPHENOL)
GAS
SOLENOID
SEC
THERMOSTATS
_
+
115
VAC
30
VAC
60
VAC
80
VAC
40 VDC
40
VDC
40 VDC
24 VDC
20 VDC
PWM
SIGNALS
+15/-15/+5 VDC
SHIELDED
CABLE
GUN TRIGGER AND THUMB SWITCH
SHIELDED CABLE AND SPI COMMUNICATIONS ARCLINK
+5 VDC
CURRENT
FEEDBACK
VOLTAGE
FEEDBACK
FROM WELD
CONTROL BOARD
TO FAN RELAY
IGBT
DRIVE
T
A
C
H
CHOPPER
(Below code 10900)
Mechanical Encoders
(Above code 10900)
GAS
SOLENOID
115 VAC AUX.
RECEPTACLE