Simrad GI51, Manual, Page: 16 / 29

Simrad GI51 Gyro Interface
8
20221594 / Cb
2.7 Initial heading and heading change test
If the heading read-out from GI51 has a fixed offset or is not
following the synchro signal from the gyro compass correctly,
this section gives you some guidelines to locate the fault. First of
all make sure that the dip switches are set correctly for gearing
and synchro voltage (ref. page 4).
Recommended action
Problem
1:1 synchro Geared synchro
Compass and GI51 output
is counting in opposite
direction Interchange S1 and S3.
For a compass that can be slewed (compass card
turned), S1 - S3 can be located as follows: slew the
compass to 000°, disconnect S1 - S2 - S3. The 2 wires
between which approx. 0 V AC is measured are S1 - S3.
Compass differs
approximately 120° or
240° from GI51 output Move S1 to S2, S2 to S3 and S3 to
S1.
Compass differs
approximately 180° from
GI51 output Interchange R1 and R2.
Compass differs
approxi/-60° from
GI51 output Corrected by a combination of
swapping R1 and R2 for 180° shift
and different sequence of S1 – S2 –
S3 connections for 120° shift to
obtain the required 60° correction
(180° – 120°). Note that swapping
two phases only gives change of
direction!
Constant difference of
some degrees between
compass and GI51 output
for all headings Adjust offset as described in sec 2.5.
2.8 S9 Steering lever
The S9 Steering Lever can be added to an autopilot system to
provide remote non-follow up steering capability. The S9 is
designed to be mounted in weather exposed locations. If it is
installed in such location, it is recommended to insure that the
cable entry glands are properly tightened. In addition silicone
sealant should be added around cable to ensure water protection.
As the mode selection by the Enable signal is based on a pulse, it
is recommended that only one S9 lever is used. This because the
mode selection switch is fixed levels, not pulsed. If several NFU
levers are required, the S35 lever is recommended.