POWER BOARD, CONTROL BOARD
AND SERIAL PERIPHERAL INTER-
FACE (SPI) COMMUNICATIONS
POWER BOARD
The 28VAC auxiliary is rectified and filtered and applied
to the power board. The power board, utilizing a
switching power supply, processes the 40VDC input
and develops several regulated positive and negative
DC supplies. Three DC supplies are fed to the control
board for machine control supplies. Two positive DC
voltages are coupled to the control board for the Serial
Peripheral Communications (SPI) supplies. A +5VDC
is used for the RS232 connection supply. An over or
under input voltage detection and shutdown circuit is
also part of the power board’s circuitry. The optional
12VDC gas solenoid is powered by the remote board.
CONTROL BOARD
The control board performs the primary interfacing
functions to establish and maintain output control of
the V350 machine. The control board sends and
receives command signals from the mode or advanced
process panel, the display panel and the remote panel.
These communications are processed through a digi-
tal network called a Serial Peripheral Interface (SPI).
This network digitally communicates to and from the
control board the user’s commands and various
machine status messages. The software that is con-
tained within the control board processes and com-
pares these commands with the voltage and current
feedback information it receives from the output cur-
rent sensor and the output voltage sensing leads. The
appropriate pulse width modulation (PWM) signals
(See Pulse Width Modulation in this section) are sent
to the switch board IGBTs. In this manner, the digital-
ly controlled high-speed welding waveform is created
and regulated.
The control board also monitors the thermostats, the
main transformer primary currents and the input
capacitor voltages.
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
