Nautel XL12, Technical Instructions

Page: 121 / 238

12 000 WATT AM BROADCAST TRANSMITTER
XL12
Page 6-8
01 January 2002
6.6.5 RF ON/OFF CONTROL:
The remote
on/off control circuit must be the equivalent of a
single pole, three position (on/off/on) switch. Each
of the on positions must be spring-loaded to return to
the off position when the toggle is released. It must
be connected to apply the remote common potential
from one on-position, to the remote interface PWB's
RF ON terminal when the transmitter is to be turned
on and from the other on-position to the remote
interface PWB's
RF OFF
terminal when the
transmitter is to be turned off.
6.6.6 PRESET POWER LEVEL SELECT:
The remote preset power level select circuit should
be the equivalent of six single pole momentary
(on/off) switches. Each of the on positions must be
spring-loaded to return to the off position when the
toggle is released. Each must be connected to apply
the remote common potential to the remote interface
PWB's
OUTPUT POWER
terminal (
PWR1, PWR2,
PWR3, PWR4, PWR5
or
PWR6
) that determines the
desired power level.
6.6.7 EXCITER A/B SELECT:
The remote
exciter select circuit should be the equivalent of a
single pole, three position (on/off/on) switch. Each
on position must be spring-loaded to return to the off
position when released. It must be connected to
apply a remote common potential to the
EXCITER
SELECT
terminal (
A
or
B
) that selects the active
exciter. There must be a one second delay between
exciter select commands.
6.6.8 RF POWER TRIM:
The remote power
trim circuit must be the equivalent of a single pole,
three position (on/off/on) switch. Each of the on
positions must be spring-loaded to return to the off
position when the toggle is released. It must be
connected to apply a ground potential, from one on-
position, to the remote interface PWB's
RAISE
terminal when an increment in RF power is required
or to its
LOWER
terminal from the second on-position,
when a decrease is required.
6.6.9 SYSTEM RESET:
The system reset
circuit must be the equivalent of a single pole, single
throw (on/off) switch. It must apply a ground
potential, from its on-position, to the remote interface
PWB's
SYSTEM RESET
terminal when all latched
alarms are to be cleared and power modules reset.
A normally open/held closed spring-loaded switch
should be used.
6.6.10 PWM INHIBIT CONTROL:
The
external PWM (pulse width modulation) inhibit
switching circuit must be the equivalent of a single
pole, single throw (on/off) switch. It must be
connected to apply a ground potential, from its on-
position, to the
PWM INHIBIT
terminal when the
transmitter's RF output, is to be inhibited.
NOTE
The external PWM inhibit input is intended to be
used in conjunction with antenna switching
circuitry, to ensure RF output current is not
flowing during opening/closing of contacts in the
transmitter's RF output feed cable. The antenna
switching circuits must apply a ground to the
PWM INHIBIT terminal prior to contact opening
(disconnecting the RF load) and must maintain
this ground until contact closure has occurred
and an appropriate impedance has been
connected to the transmitter's RF output. A
residual RF leak of approximately ten watts is
present when the RF output is inhibited. The RF
output will be instantly restored to its original
level when the ground potential is removed from
the
PWM INHIBIT
terminal.
6.6.11 ALARM RECALL:
The alarm recall
circuit must be the equivalent of a single pole, three
position (on/off) switch. The on positions must be
spring-loaded to return to the off position when the
toggle is released. It must be connected to apply a
ground potential, from the on-position, to the remote
interface PWB's
ALARM RECALL
terminal when the
last event latched alarms are to be reviewed.
6.6.12 CUTBACK RESET:
Whenever the
transmitters RF output power has had three shutback
events, the RF output will be held in a cutback mode.
The cutback mode can be reset (RF output return to
normal power) momentarily pressing the
RAISE
or
LOWER
RF power trim control.
6.6.13 RF PERFORMANCE MONITORING:
The transmitter provides outputs that are
representative of the forward power level, reflected
power level and RF envelope for external monitoring.
These outputs are available on remote interface
PWB.