Sea Tel 9711-92 Installation And Operation Manual Download Page 63

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9711-92 Ku-Band TXRX

Setup – Ships Gyro Compass

5-1

Setup – Ships Gyro Compass

The Ships Gyro Compass connection provides true heading (heading of the ship relative to true North) input to the system. This

allows the ACU to target the antenna to a “true” azimuth position to acquire any desired satellite.
After targeting this input keeps the antenna stabilized in azimuth (keeps it pointed at the targeted satellite azimuth). In normal
operation when viewing and ADMC recording in DacRemP, the “Relative Azimuth” trace should do exactly

equal and opposite

to whatever the Heading trace does and the “Azimuth” trace should stay flat.
In normal operation the heading display in the ACU should at all times be the same value as the reading on the Gyro Compass
itself (this is also referred to as Gyro Following.).
If the ACU is not following the Ships Gyro Compass correctly (un-erringly) refer to the Troubleshooting Gyro Compass

Problems.

5.1.

Gyro Type

The GYRO TYPE parameter selects the type of gyro compass interface signal, the appropriate hardware connections

and the ratio of the expected input signal for ship turning compensation. Default GYRO TYPE parameter for all
systems is 0002 so that the ACU will properly follow for Step-By-Step or NMEA gyro signals.
The GYRO TYPE parameter must be set correctly to properly read and follow the ship’s Gyro Compass signal that is

being provided. The acceptable settings are:

362

for 360:1 Synchro with S/D Converter

for 90:1 Synchro with S/D Converter

for 36:1 Synchro with S/D Converter

for Step-By-Step gyro or NMEA gyro

for 1:1 Synchro with S/D Converter

for No Gyro linear AZ Search Mode (No Heading input available)

5.2.

Updating the GYRO TYPE parameter

To manually update, press the LEFT arrow key to bring the cursor under the least significant character. Continue to
move the cursor until the desired character to be edited is underscored (selected). Use the UP or DOWN arrow keys to

increment or decrement the selected character.
Use the LEFT or RIGHT arrow key to move the cursor left or right to select other characters to modify. When you are

finished modifying press ENTER to execute the new value OR press NEXT to abort and exit setup mode.
When you are finished making parameter changes, go to the SAVE NEW PARAMETERS display to save the changes you

have made.

5.3.

If there is NO Ships Gyro Compass

Without heading input to the system the ACU will

NOT

be able to target, or stay stabilized

, a “true” azimuth

pointing angle. This will make satellite acquisition much more difficult and the true azimuth value that any given

satellite should be at will not be displayed correctly.

This mode of operation is NOT recommended for ships

. A better solution would be to provide a Satellite

Compass (multiple GPS antenna devices) to provide true heading input to the ACU. These devices are readily available

and are much less expensive than a Gyro Compass.
If there is NO Gyro Compass (ie on a large stationary rig which is anchored to the ocean floor) set the GYRO TYPE
parameter to 0000, the SWEEP INC parameter to 0047 and SAT REF (Satellite Reference Mode)

MUST

be turned

ON.

This combination of settings will cause “No Gyro” Search pattern to be use to find the desired satellite (refer to the

setup – Searching lesson).