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 and a
+40VDC is fed to the remote board to power an
optional gas solenoid. An over or under input voltage
detection and shutdown circuit is also part of the
power board’s circuitry.
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 panel, the
status panel, the display panel and /or the optional
remote panel. These communications are processed
through a digital 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 contained within the control board processes and
compares these commands with the voltage and cur-
rent feedback information it receives from the output
current 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.
