Sea Tel DAC-2202 Installation And Operation Manual Download Page 45

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DAC-2202 Antenna Control Unit

Setup

5-13

5.28.

REMOTE MONITOR

Use to monitor the results of a diagnostic command which was sent to the PCU. Refer to your antenna manual.

5.29.

To Disable/Enable DishScan

To be able to use Step Track, or to revert to Conscan, as your active tracking mode you will have to disable DishScan.
Select the DISHSCAN parameter window on the ACU:

Press the

RIGHT

arrow, then press the

arrow and last press the

ENTER

key to turn DishScan mode ON.

Press the

RIGHT

arrow, then press the

DOWN

arrow and last press the

ENTER

key to turn DishScan Mode

OFF.

If you change this remote parameter, you must save the change using

REMOTE PARAMETERS

If DishScan is OFF and the Step Integral parameter is set to 0000, you will get a constant ERROR 0016 (DishScan error)
and you will see zeros flashing in the lower left of the Azimuth and Elevation ENTRY menu displays. This is a visual
indication that DishScan is turned OFF.

5.30.

Satellite Reference Mode

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 there is no gyro compass or if the input is corrupt,
not stable or not consistently accurate the tracking errors will become large enough to cause the antenna to be mis-
pointed off satellite.
Satellite Reference Mode will uncouple the gyro reference from the azimuth rate sensor control loop.  When operating
in Satellite Reference Mode changes in ships gyro reading 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.

I t should normally be

OFF

as long as you have an accurate, reliable, gyro compass input available.

MUST

OFF

when the elevation angle is greater than 75 degrees. Above 75 degrees Elevation, the ability of Sat

Reference tracking to correct the Az Rate sensor bias begins to degrade, especially on a circular C system.

Satellite Reference Mode

MUST be ON when:



No Gyro Compass is available.



The Gyro Compass input is noisy, occasionally inaccurate or occasionally unavailable.



Frequent or constant ACU Error Code 0001 (Gyro Compass has failed).



Using an

uncompensated

Flux Gate Compass.

To view, or change, the Satellite Reference Mode status,

select the SAT REF remote parameter:

Press the RIGHT arrow, then press the UP arrow and last press the ENTER key to turn Satellite Reference Mode
ON.

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.

5.31.

REMOTE TILT

Allows easy access to the tilt adjustment commands. Refer to your antenna manual. Press LEFT or RIGHT arrow bring
up the cursor and begin adjustment. Press UP/DOWN arrow to adjust tilt forward and back. Press LEFT/RIGHT to
adjust the tilt left and right. Press ENTER to restore normal system operation. (You must save the new tilt settings
using the REMOTE PARAMETERS function below.