22.
ANTENNAS
22.1
Section in process.
23.
ALIGNMENT
DATAFLOW RTU
23. I
The only alignment procedure required for the
DAT
AF
LOW RTU
control board is adjustment of the deviation.
Normally, the deviation should not require realignment. This adjustment controls the amount of deviation
produced by the RF board. Refer to the following procedure to properly perform this alignment.
RECOMMENDED TEST EQUIPMENT
I.
DATAFLOW RTU
programming kit.
2.
PC compatible computer.
3.
BvI deviation meter.
PREPARATION
I.
Connect the
DATAFLOW RTU
programming kit to the unit to be tested.
2.
Configure
theDATAFLOW RTUto
transmit on channel 460 MHz for UHF systems, or 154 MHz for
VHF
systems.
For instruction on the use of the programming software see the
DATAFLOW RTU
Software/ Programmers Manual.
3.
Locate RBI on the control board. Ifa battery board covers the control board, Rl31 is located under
a hole in the battery board. The battery board does not need to be removed to access RI3 I.
DEVIATION ALIGNMENT
I.
Execute the
DATAFLOW RTU
transmitter test. This will cause the
DATAFLOW RTU
to transmit a
15-second test pattern. For instruction on the use of the programming software, see the
DATAFLOW
RTU
Software/Programmers Manual.
2.
Using an adjustment tool, adjust RI31 for a deviation of2.80 kHz to 3.00 kHz.
23.2
Refer to the applicable RITRON DTX manual for alignment of the RF board. When using the DTX manual in
support of the
DATAFLOW RTU
only the RF portion is valid. Disregard all references to the DTX control
board.
24.
THEORY OF OPERATION
24.1
The
DATAFLOW RTU
control board performs many functions. It is used to program and control the DTX RF
board. It is the real-world interface for the telemetry inputs and outputs. It communicates to devices over an RS-
485 serial link. The following paragraphs describe how individual blocks of the control board operate.
24.1. l +5V REGULATOR:
ICIOl
is a DC-to-DC converter that changes the VUNREG input
voltage to +5VDC. The +5VDC value is set by resistors R!0l, RI02, and RI03 with FB = 2.50V (pin 13). This
IC also contains an output comparator used to monitor 5VDC voltage. This comparator shuts the
system down
if
low power is detected to prevent abnormal system operation due to low voltage.
24.1.2 VREG REGULA TOR:
IC112
is a DC-to-DC converter that changes the VUNREG input
voltage to +8.5VDC. The +8.5VDC value is set by resistors R!48 and R!49 with ADJ= 1.23V (pin 5). This IC
also contains an ENABLE pin (pin I) which allows the microprocessor to tum this regulator ON and OFF. With
5V applied to the ENABLE pin, the regulator is ON; with 0V applied to the ENABLE pin, the regulator is OFF.
24.1.3 4 Hz. INTERRUPT CLOCK:
IC102
provides a 4 Hz. clock to the microprocessor, which
functions as an interrupt timer to make the microprocessor read all the digital and analog inputs. The 4 Hz. rate
is made by dividing the 32768 Hz. crystal (YIOI). To save power, ICI02 is not run at full +5V. Diodes CRI03
and CRI04 are used to decrease the supply voltage to ICI02.
( A-19)
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