or can provide a logic LOW output when a pull-up resistor to +5
to +15 VDC is used. Maximum safe voltage at a status output
terminal is +15 VDC and maximum safe current into a status
output is 100 mA.
2.17.3.1
Explanation Of Selected Remote Control Functions
Most remote control functions and monitor outputs are the same
as the corresponding functions or indications in the transmitter.
Some indications and functions will, however, be explained here
to aid in planning and installing a remote control system.
a. OFF Control: Use for normal transmitter turn-off, for
example, at the end of the operating day. The external OFF
control operates the same as the front panel OFF button
and turns off the PA Power supply.
b. EXTERNAL PA TURN OFF: Use to remove RF output
during antenna pattern switching or for other RF switching
operations. Because the transmitter RF output returns as
soon as the PA Turn Off control input voltage is removed,
PA Turn Off MUST NOT be used for failsafe or safety
interlock purposes. A PA Turn Off input turns all PA
Modules OFF through modulator section action, causing
RF output to go to zero. The PA is held OFF as long as the
External PA Turn Off input is active. As soon as the
External PA Turn-Off signal is removed, the transmitter
immediately comes back up to its pre-set operating power.
The External PA Turn-Off command does NOT turn off
the PA Power supply and will NOT result in any red LED
indication on the ColorStat™ panel. However, segment
nine of DS1 on the Modulation Encoder (A37) will illumi-
nate RED whenever there is an active PA Off command.
The External PA Turn-Off provides the same function as
the PA OFF switch S2 on the Controller.
NOTE
PA TURN OFF should NOT be used for FAILSAFE purposes, for
interlocks, or for routine transmitter turn off. It is intended to
remove RF output during antenna switching operations.
c. EXTERNAL INTERLOCK is used for Failsafe and for
safety interlocks on any enclosure which would permit
contact with RF output, such as phasors or antenna switch-
ing equipment.
d. TRANSMITTER ON does not use a separate ON switch.
The transmitter comes ON at the desired power level when
a momentary remote control input (at least 100 mS long)
is provided at the LOW, MEDIUM, or HIGH terminals on
TB1. If the transmitter is already ON, providing another of
these inputs will change power level without interrupting
RF output.
e. RAISE/LOWER inputs change the RF power. A RAISE
input will cause transmitter power output to INCREASE
for as long as the control input is provided, or until the
transmitter power output reaches the maximum power
limit. A LOWER input will cause transmitter power output
to DECREASE for as long as the control input is provided,
or until the power output reaches zero.
NOTE
When remote control and monitoring is used, delays in data
transmission can delay the remote output power reading while
the RAISE or LOWER controls are being operated. This can
cause the remote output power reading to continue to change for
a short time after the RAISE or LOWER command is stopped.
f. FORWARD and REFLECTED POWER (Remote Meter
Reading) outputs correspond to the transmitter FOR-
WARD and REFLECTED power meter indications. Note
that the transmitter power meter scale is not linear. The
voltage outputs at Forward remote output TB1-3 and Re-
flected remote output TB1-4 are proportional to the RF
output voltage which is proportional to the square root of
the RF power.
g. BANDPASS FILTER VSWR and ANTENNA VSWR (Re-
mote Meter Reading) outputs are uncalibrated, relative
readings from the VSWR phase detectors on Output Moni-
tor.
1. BANDPASS FILTER VSWR corresponds to the DE-
TECTOR NULL (FILTER) reading on the transmitter
front panel multimeter. A change in the Bandpass Fil-
ter/Output Network of the transmitter will cause the
reading to increase.
2. ANTENNA VSWR corresponds to the DETECTOR
NULL (ANTENNA) reading on the front panel mul-
timeter. A mismatch in the antenna system will cause
the Antenna VSWR reading to increase. Antenna
VSWR is an uncalibrated, relative reading, but is more
sensitive than Reflected Power.
h. RF DRIVE ESTIMATE (Remote Meter Reading) is an
UNCALIBRATED sample of the RF drive to the PA
Modules and corresponds to the RELATIVE RF DRIVE
position on the front panel Multimeter.
i. MONITOR SIGNALS: +22 VDC, -22 VDC, +8 VDC, And
-8 VDC (Remote Meter Readings) are samples of unregu-
lated voltages from the low voltage power supply, and will
in3.4 VDC for positive supplies and -3.4 VDC for
negative supplies during typical operation.
DX-25U
2-14
888-2297-002
Rev. AA: 8/9/2000
WARNING: Disconnect primary power prior to servicing.
