1-1
SECTION I
TRANSMITTER CONTROLLER THEORY OF OPERATION
1-1.
INTRODUCTION.
1-2.
The following text provides theory of operation with supporting diagrams for the FM-5T/
FM-5TS transmitter controller.
1-3.
GENERAL DESCRIPTION.
1-4.
All transmitter control and monitoring functions are performed by a microprocessor based
controller (refer to Figure 1-1). The controller is designed to monitor the status of several
transmitter parameters and perform control actions when required. The controller will
interface with almost any remote control device such as the Broadcast Electronics VMC-16
remote control system.
1-5.
The controller is equipped with 12 switch/indicators, 4 overload indicators, and 5 status
indicators. Controller processing power is provided by a Z-Soft microcontroller. The
microcontroller is housed on a small plug-in circuit board. The microcontroller circuit
board is designed to plug directly into a header on the controller main circuit board.
1-6.
The controller circuitry includes a front-panel modem port, one rear-panel modem port,
one rear-panel local port, and a printer port. The modem ports and the printer port are
designed to be used with a future remote monitoring and diagnostic system. The rear-
panel local port is for interfacing to a future dual/main/alternate transmitter control sys
tem.
1-7.
A Lithium battery back-up system is included in the controller design. The battery back-
up system will maintain the controller memory and other parameters during a power fail
ure. This system allows the transmitter to return to operation after the power failure in
the exact same operating conditions.
1-8.
A modular switching power supply provides operating potentials for the controller circuit
ry. Power supply status indications are provided by +15V, -15V, and +5 V indicators.
1-9.
FUNCTIONAL DESCRIPTION.
1-10.
The following text presents a description of the major functions performed by the transmit
ter controller. The text describes controller operations during major transmitter functions
such as turn-on and automatic power control.
1-11.
TRANSMITTER TURN-ON.
1-12.
Commands such as filament on and high voltage on are initiated by the front-panel
FILAMENT ON
and
HIGH VOLTAGE ON
switch/indicators. A one-button-start may
be selected by depressing only the
HIGH VOLTAGE ON
switch/indicator. As each switch
is depressed, the associated switch/indicator will illuminate to indicate that the selected
command has been received and stored.
1-13.
Assuming the
FILAMENT ON
and/or
HIGH VOLTAGE ON
switch/indicators have been
depressed and all internal interlocks are closed, the blower will start. The internal inter
lock closed condition is identified by the illumination of the front-panel
INTERLOCK
in
dicator.
Summary of Contents for FM-5T
Page 1: ...FM 5T FM 5TS 5 KILOWATT FM BROADCAST TRANSMITTERS July 1999 IM No 597 0033 014 ...
Page 14: ...1 3 FIGURE 1 1 FM 5T FM 5TS TRANSMITTER 597 0033 1 COPYRIGHT 1990 BROADCAST ELECTRONICS INC ...
Page 29: ...2 13 COPYRIGHT 1997 BROADCAST ELECTRONICS INC 597 0033 415 FIGURE 2 4 TRANSFORMER TAPS ...
Page 32: ...2 16 597 0033 406 FIGURE 2 6 FM 5T PRIMARY AC WIRING COPYRIGHT 1997 BROADCAST ELECTRONICS INC ...
Page 46: ...3 9 TABLE 3 2 INDICATOR CHECKLIST 597 0098 412 ...
Page 61: ...4 19 FIGURE 4 5 PA CAVITY 597 0032 32 COPYRIGHT 1997 BROADCAST ELECTRONICS INC ...
Page 83: ...5 22 WARNING DISCONNECT POWER PRIOR TO SERVICING BLANK PAGE ...
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