10/6/10
888-2629-200
4-27
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation
Maxiva ULX COFDM Series
Pin 7 of the cabinet bus carries the PA_voltage_select signal from the MCM card to the
IPA and PA backplanes. Its function is to set the output voltage of the AC to DC
converters in the PA (and IPA) modules. Table 4-13 gives the control voltage levels and
the corresponding PA and IPA module AC to DC converter output voltage.
4.4.9
Parallel Control Lines
The parallel control lines are used for quick actuation of critical functions, such as ON,
OFF, RF mute, PS adjust, and Fault Off. These lines are also the backup control lines in
Life Support mode when the PCM (and therefore the system CAN bus) is not
operational. The MCM card in each cabinet can independently activate some or all of
the parallel control lines to maintain operation and protect the transmitter in case of a
fault or other condition that may adversely affect the transmitter. These parallel control
signals are duplicated in the CAN messages. The following is a brief explanation of
each of the parallel control lines included in the system control bus.
a.
SYS_ON_CMD
This command corresponds to the transmitter operator pushing the "ON" button,
This signal is high for ON and produced by the MCM card in the TCU.
b.
/SYS_OFF_CMD
This command corresponds to the transmitter operator pushing the "OFF" button.
The signal is low for OFF and produced by the MCM card in the TCU.
c.
/SYS_RESTRIKE
When the transmitter is already turned ON and the operator presses the "ON"
button, this line will be pulsed low for a minimum of 100ms. This will cause all
controller boards to reset any faults and status and try to return to normal
operation. This line is a sense only line for the rest of the control boards.
This command is basically a RESET pulse which will try to turn on any
transmitter components which have faulted off due to a critical fault condition. If
they are still faulty, this will be detected and the component will simply be shut
off again. This will not reset or clear the Fault Log.
Table 4-13 PA Module Power Supply Output Voltage Control
PA_Voltage_ Select Voltage
Power Supply Output Voltage
5.755 Vdc
44Vdc
4.122 Vdc
46 Vdc
2.490 Vdc
48 Vdc
0.875 Vdc
50 Vdc
Содержание Maxiva ULX
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