NORTHROP GRUMMAN naviguide 4000, User, Installation And Service Manual

Page: 85 / 252

NAVIGUIDE 4000 056336 Rev. AA
5.2: Configuring the Steering Gear Control Page 5–3
5.2 Configuring the Steering Gear Control
5.2.1 Configuring Bang-Bang Steering Control
When Bang-Bang steering control is used, each SCU is equipped with one or two
solenoid daughter PCBs. Each solenoid daughter PCB contains two separate con-
trol sections with the corresponding outputs for AC or DC solenoid valves. In addi-
tion, the daughter PCBs contain two opto-isolated status inputs for monitoring the
„Pump On“ status signal for each output section.
5.2.1.1 Staging Output Sections
The NAVIGUIDE 4000 system allows to stage the available solenoid output sec-
tions for a given rudder. When staging is used, not all sections are activated at
once, but depending on the rudder error (the difference between the ordered and
the actual rudder angle), stages above the first stage („Stage 1“) are successively
activated and deactivated.
When equipped with two solenoid daughter PCBs, one SCU can provide up to four
control stages. Two SCUs controlling the same rudder can provide up to eight
stages, where staging alternates between the two SCUs.
Fig. 5–1:
Staging sole-
noid outputs
The „Rudder On“ and „Rudder Off“ thresholds at which Stage 1 is activated and
deactivated are configurable in the SCU setup. The threshold values for higher
stages are fixed and cannot be altered.
When the output sections’ „Pump On“ status inputs are used, the SCU will use in-
clude only sections with an active „Pump On“ status into the staging scheme. For
example, if the „Pump On“ status of a Stage 2 section is inactive and the status of
a Stage 3 section is active, the Stage 3 section will act as if it were configured for
Stage 2 operation.
ACTIVE
ACTUAL 0.0
ACTIVE
ACTUAL 30.0
"st. 1 off"
≤
2°
≤
4°
≤
6°
≤
8°
≤
10°
≤
12°
≤
14°
"rudder off"
threshold
"st. 1 on"
2 SCUs
master stage 1
slave stage 1
master stage/dump 2
slave stage/dump 2
master stage/dump 3
slave stage/dump 3
master stage/dump 4
slave stage/dump 4
1 SCU
stage 1
stage/dump 2
stage/dump 3
stage/dump 4
≥
3°
≥
5°
≥
7°
≥
9°
≥
11°
≥
13°
≥
15°
rudder controlled by
"rudder on"
threshold