4-8
888-2523-001
7/26/05
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation
ATLAS Analogue
e.
/PS_MUTE
The /PS_MUTE line shuts down the output of the 32 Volt PA module supplies
temporarily until the fault condition is cleared. This is a non-latching signal. The
Main Controller, Power Block Controller, External I/O and RF Monitor Boards
monitor this line and have the ability to activate it if necessary.
f.
/AC_LOW
This signal is an early warning of impending loss of control voltage. When the
AC line voltage that powers the LVPS(s) drops below an acceptable threshold the
board will pull this open collector line low. Phase samples L3-L1 (C-A) are
continuously monitored. The other boards in the control system will use this
indication as an advanced warning to save any data and prepare for loss of power.
The Power Block Controller board is the only control board with the ability to
drive this signal and it will affect the Main Controller, External I/O and RF
Monitor Boards.
g.
ALC - Automatic Level Control. The ALC signal is used to control the
transmitter power output and is normally sent digitally over the CAN bus. This
line carries a voltage from the Main Controller to the PA Modules which is an
analog version of the digital ALC signal sent over the CAN bus. It is a backup
signal only used by the modules if the CAN bus fails and the modules lose
communication with the Main Controller. If the CAN bus is operational, this
signal is not used.
4.3.5
Main Controller
The Main Controller is the primary interface between the transmitter and the operator
via the front panel Graphical User Interface or GUI. It is connected to all transmitter
subsystems, both internal and external to the transmitter, through either an RS-485
serial port or the CAN (Controller Area Network) bus and dedicated parallel control
lines. The CAN bus and the parallel control lines are distributed on a single multi-
conductor cable called the System Control Bus.
The Main Controller is mounted directly behind the front control panel. It is directly
connected to the front panel switchboard which is considered a "Mezzanine" board. The
front panel switchboard uses a CPLD to serialize the I/O (the control lines and status
signals) to and from the Main Controller.
Summary of Contents for ATLAS ANALOGUE
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