Harris Atlas DVL400, Technical Manual

Page: 134 / 180

4-34 888-2473-001 2/25/03
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation ATLAS Series™
4.5.4.2 LVPS Interface and Cabinet ID
The PS Monitor Board controls the low voltage power supplies and acts as the
distribution point for the low voltage to the rest of the system. If the dual LVPS
option is used, then the 2 supplies will be diode or’ed on this board to provide
redundancy should one supply fail. The CAN bus would then be used to send the
fault status of the failed supply to the Main Controller to alert the operator.
There are 2 Power Bus cables, J8 and J9, which carry the +7.5Vdc and +/-15Vdc
from the LVPS and the Cabinet ID (Identification) from dipswitch S3. J9 connects
to the Backplane Interface board for distribution of low voltage and Cabinet ID to
the PA modules. J8 distributes low voltage and cabinet ID to the RF Monitor Board,
External I/O Board, DCU (Drive Control Unit) and the Main Controller. This
allows one dipswitch to set the cabinet ID for all other sub-assemblies in the PA
cabinet reducing the possibility of an error in setting the cabinet ID on each board.
4.5.4.3 PA Power Supply Monitoring and Control
The PS Monitor board monitors the DC OK outputs from each of the PA Power
Supply modules in the transmitter cabinet. There may be from one to four power
supplies in each cabinet, depending on the transmitter model. The Power Supply
Monitor board also interfaces and controls the remote enable/disable function on
each supply. Should a fault off condition or a power supply mute condition exist,
the PS Monitor board will disable the outputs of the PA supplies. These lines are
monitored and controlled by the CPLD. The PS Monitor board has a bicolor status
LED for each PA Power Supply. See Table 4-4 on page 4-38, for a listing of all PS
Monitor board LEDs. The control and status lines for the power supplies are:
a.
PA Supply Voltage Adjust (only used on 3-Phase supplies)
This is an analogue voltage used to adjust the DC output of the PA power
supplies to optimise efficiency of the PA Modules across the entire UHF
band. This voltage is obtained from a lookup table in the software, based on
the operating frequency entered into the Configuration screen of the GUI.
b.
PA Supply Disable
The Power Supply Monitor board interfaces to each of the PA power supply's
disable signal. When a condition exists that requires the PA supply output to
be shut off, the Power Supply Monitor will pull this signal low.
c. PA Supply DC OK
The Power Supply Monitor board will monitor the DC OK signal from each
of the PA power supplies. A 5 volt level from the PA supply indicates the DC
is okay while a 0 volt level represents a DC fail condition. This information
will be reported via the CAN network.