Harris Atlas DVL400, Technical Manual

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4-32 888-2473-001 2/25/03
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation ATLAS Series™
The proper voltage is then obtained from a frequency table in the PS Monitor
software and is not directly user adjustable. Nominal operating voltage at the
frequency tested can be obtained from the factory test data which shipped with the
transmitter.
4.5.3 Low Voltage Power Supplies (LVPS)
The standard cabinet configuration comes with a single Low Voltage Power Supply
or LVPS. A second LVPS is optional. The supplies are located near the middle of
the cabinet and are accessed from the front of the transmitter. The outputs from the
LVPS are connected to the PS Monitor Board.
For Dual LVPS systems, the outputs from the 2 supplies are diode or’ed together on
the Power Supply Monitor Board. Should one supply fail, the low voltage will still
be available throughout the transmitter. The failure will be reported via CAN to the
main controller in order to alert the transmitter operator.
The Power Supply Monitor Board also acts as a distribution point for low voltage to
the rest of the transmitter. The outputs from the LVPS are:
•
+7.5Vdc @ 100W (13.3A) - This voltage is used to drive all the logic
contained on the various control boards throughout the Atlas transmitter.
The 7.5 volt output will be regulated on each board with a linear
regulator to step down the voltage to 5Vdc and/or 3.3Vdc as needed.
•
+15Vdc and -15Vdc @ 75W (5A) each - These voltages are used as the
supply for biasing op-amps and other analogue circuitry for each board.
Each of the three output voltages of the LVPS will be monitored by the Power
Supply Monitor Board. The +7.5V output is fused with a 10Amp fast acting fuse
while both the +15V and -15V outputs are fused with a 5Amp fast acting fuse for
each polarity. The AC supply input is auto ranging and will accept 180-264Vac at a
frequency of 47 to 63 Hz.
4.5.4 Power Supply Monitor Board
The Power Supply (PS) Monitor Board monitors and controls the various power
supplies and monitors the internal transmitter cooling. It uses the 376 micro module
and is interfaced to the Main Controller via the CAN bus and the parallel control
lines (System Control Bus). As is standard with all of the control boards, a CPLD is
used for processing the digital I/O and interfaces with the micro-module. This
allows the CPLD to be able to provide control and status monitoring in the event
that the CAN bus or micro-controller fails. The following paragraphs give a detailed
description of the individual PS Monitor Board functions.