Navitron
Systems Ltd
Autopilot Types NT951G & NT991G MK2
Technical Specifications

Whilst the NT951G and NT991G MK2 autopilots are similar in appearance and apparently identical in terms of the parameters specified below, it should be noted that the software structures differ significantly to reflect the steering and response characteristics of vessels up to approximately 2000 grt (NT951G) compared with larger vessels from approximately 2000 grt upwards (NT991G MK2).

Certification Standards: -
Fully Type Approved to ISO 11674 & IMO A342 (IX) as amended by MSC64/67 Annex 3.
Wheelmarked in accordance
with MED 96/98/EC

Autopilot Input / Output Specifications

Inputs: -
Outputs: -
Supply Voltage Range
11-40Vdc
NMEA 0183 Heading Data (Isolated RS422)
Power Consumption
2.5W (@24Vdc)
Update
Rate
Selectable @
1Hz, 10Hz or 20Hz
Illumination Max
8.1W (@24Vdc)
 Sentence Types (Mag/Gyro
versus
Update Rate)
Hz
Mag
Gyro
Mag Heading Input Ports: -
1
HCHDM
 
Navitron Heading Sensor Coil mounted above or below existing Mag compass
Coil type
HSC1 or HSC2
HCHDG
HEHDT
APHDM
AGHDT
APHDG
 
10
HCHDM (5Hz)
HEHDT
Resolution
0.25°
HCHDG
AGHDT (5Hz)
20
HCHDM
HEHDT
NMEA 0183 Heading Sentence from Electronic Compass (Priority and max update rate as shown)
XX HDM
25Hz
Resolution
0.1°
XX HDG
16Hz
Autopilot status data
1
APRSA
APHTD
AGRSA
AGHTD
XX HCC
28Hz
Furuno Heading Format: -
XX HDT
25Hz
Update Rate
Selectable @
5Hz or 40Hz
Resolution
0.1°
Resolution
Selectable @
0.166 or 0.1
Gyro Heading Input Ports: -
Isolated 1:1 Synchro
(if available in Gyro)
400Hz Excitation
from Autopilot
Signal Amplitude
Selectable @
5Vdc or 12Vdc
Resolution
0.25°
Step by Step Heading Data: -
NMEA 0183 Heading Sentence from Gyro or optional NT925HDI (Priority and max update rate as shown)
XX HDT
25Hz
Steps per degree
Selectable @
3, 6, 12 or 24
XX HDM
25Hz
XX HDG
16Hz
Signal Amplitude
5Vdc
XX HCC
28Hz
Resolution
0.1°
Navitron Custom Serial Heading Data: -
(to Navitron Digital Repeaters)
Follow Up Rate (Minimum): -
All Heading Input Types
30° / Sec
Navitron Serial Input/Output Data: -
(to / from Navitron Bowthruster Interface,
Analogue Steering & Dual Steering Interface options)

NT991G MK2 Heading to steer data accepted
(from GPS/Plotter etc. for Track mode use)

NMEA 0183
Sentence types
XX HTC
Solid State Solenoid Switching: -
XXHSC
Polarity
Selectable @
Common +VE/-VE
XXAPB
 
Max Rating
5A (11-40Vdc)
 
Panel Alarms: -
Operating Temp Range
-20 to +60 °C
Power Fail
(int / ext supply fail)
Steering Fail
(no rudder response)
Operator Controls & Selectors: -
Heading Input
(no heading data)
Yaw
  Alarm Test/Cancel Deg / min/sec
(ROT Status)
Rudder Autotrim On/Off Off Course
(specified limit exceeded)
Counter Rudder Turn Rate Rudder Limit
(specified limit reached)
Rudder Limit Off Course Alarm level Remote
(remote station engaged)
Illumination +1° / -1° keys (NT951G) Alarm Test
(tests all alarms)
Mode Switch
OR
Gyro/Mag Selector Cancel/Confirm keys
(NT991G MK2)
Mechanical
NT951G/991G MK2 Control Unit
Width
297mm
Height
176mm
Compass Safe Distance: -
Depth - behind
bezel
110mm
NT951G/991G MK2
Control Unit
0.6m
Weight
3.3Kg

Click for information on the NT920NFU Click for information on the NT920NFU Click for NT951G & NT991G MK2 Control Unit Outline & Mounting Dimensions Click for information on the NT921BTI Click for information on the NT925HDI Click for information on the NT920URB Click for information on the NT920AHR Click for information on the NT920DHR Click for information on the NT920NFU Click for information on the NT920WA Click for information on the NT920RAI Click for information on the NT990ASI Click to view image of the NT920RRU

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