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Principles of Operation
7.4.4.3. SYNC/DEMOD STATUS LED'S
LED
D1
M/R Sensor Status
D2
Segment Sensor
7.4.4.4. PHOTO-DETECTOR TEMPERATURE CONTROL
7.4.4.5. DARK CALIBRATION SWITCH
7.4.4.6. ELECTRIC TEST SWITCH
7.4.5. Relay Board
212
The following two status LED's located on the synch/demod board provide
additional diagnostic tools for checking the GFC wheel rotation.
Table 7-1:
Sync/Demod Status LED Activity
FUNCTION
Status
See Section 8.1.4 for more information.
The synch/demod board also contains circuitry that controls the IR photo-
detector's thermoelectric coolers. A drive voltage, PHT DRIVE, is supplied to
the coolers by the synch/demod board which is adjusted by the synch/demod
board based on a return signal called TEC control which alerts informs the
synch/demod board of the detector's temperature. The warmer the detector, the
harder the coolers are driven.
PHT DRIVE is one of the Test Functions viewable by the user via the front
panel. Press <TST or TST> until it appears on the display.
This switch initiates the Dark Calibration procedure. When initiated by the user
(see Section 4.13.6 for more details), the dark calibration process opens this
switch, interrupting the signal from the IR photo-detector.
analyzer to measure any offset caused by the synch/demod board circuitry.
When active this circuit generates a specific waveform intended to simulate the
function of the IR photo-detector but with a known set of value which is
substituted for the detector's actual signal via the dark switch. It may also be
initiated by the user (see Section 4.13.5 for more details).
By actuating various switches and relays located on this board, the CPU controls
the status of other key components. The relay board receives instructions in the
form of digital signals over the I
activates its various switches and relays appropriately.
Teledyne API Model T360/T360M Operation Manual
STATUS OK
LED flashes approximately
2/second
LED flashes approximately
6/second
2
C bus, interprets these digital instructions and
FAULT STATUS
LED is stuck
ON or OFF
LED is stuck
ON or OFF
This allows the
07272B DCN6552
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