Sea Tel DTV04, Инструкция по установке и эксплуатации

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DTV04 HD TVRO Antenna Troubleshooting and Maintenance
7-5
7.3.7.
For testing and calibration purposes you may need to temporarily disable DishScan (and thus the
drive is produces).
To turn
DISHSCAN drive off:
To Disable/Enable DishScan
1. Using the ACU front panel, Select the Setup Remote Parameter “
DISHSCAN
”:
2. Press the
RIGHT
arrow.
3. Press the
UP
arrow (verify status changes to “OFF”).
4. Press the
ENTER
key.
If DishScan is
OFF
and the
Step Integral
parameter is set to
0000
, you will get a constant ACU
ERROR
0016
(DishScan error) and you will see zeros flashing in the lower left of the Azimuth and
Elevation ENTRY sub-menu displays. This is a visual indication that DishScan is turned OFF.
To turn
DISHSCAN
drive on:
1. Using the ACU front panel, Select the Setup Remote Parameter “
DISHSCAN
”:
2. Press the
RIGHT
arrow.
3. Press the
UP
arrow (verify status changes to “ON”).
4. Press the
ENTER
key.
DO NOT SAVE this parameter disabled to the P edestal C ontrol U nits NVRAM unless doing so for a
specific system test. DishScan drive and signaling is
required
for normal operation. A failure to
operate with DishScan enabled will result in degraded system performance due to the direct
inability to make proper tracking decisions.
7.3.8.
The ships gyro compass input to the ACU may be accurate and stable in static conditions and yet
may NOT be accurate or stable enough in some underway dynamic conditions. If the gyro
compass input is corrupt, not stable the errors will become large enough to cause the antenna to be
mis-pointed off satellite as the system compensates for what it assumes to be actual vessel
movement .
Satellite Reference Mode will uncouple the gyro reference from the azimuth rate sensor control
loop. This decoupling of the Gyro source only happens 2.5 minutes after an azimuth command has
been sent to the antenna by means of an AZ target command, a search pattern initiated, or the a
Satellites is retargeted. When operating in Satellite Reference Mode changes in ships gyro reading
will reflect its changes to the ACU’s display but will not directly affect the azimuth control loop.
The Pedestal Control Unit will stabilize the antenna based entirely on the azimuth rate sensor loop
and the tracking information from DishScan. This will keep the azimuth rate sensor position from
eventually drifting away at a rate faster than the tracking loop can correct by using the tracking
errors to regulate the rate sensor bias.
Satellite Reference Mode can be used as a diagnostic mode to determine if tracking errors are
caused by faulty gyro inputs.
Satellite Reference Mode enabled is the recommended mode of operation regardless of GYRO type.
To view, or change, the Satellite Reference Mode status, select the SAT REF remote parameter:
Satellite Reference Mode
1.
Press the RIGHT arrow, then press the UP arrow and last press the ENTER key to turn
Satellite Reference Mode ON.
2. Press the RIGHT arrow, then press the DOWN arrow and last press the ENTER key to turn
Satellite Reference Mode OFF.
If you change this remote parameter, you must save the change using REMOTE PARAMETERS.