Navitron
Systems Ltd
Autopilot Types NT921G & NT990G
Technical Specifications

Whilst the NT921G and NT990G 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 (NT921G) compared with larger vessels from approximately 2000 grt upwards (NT990G).

Certification Standards: -
Russian Martime Register of Shipping (R.M.R.S) and Morsviasputnik Type Approved in accordance with ISO 11674 & IMO A342 (IX) as amended by MSC64/67 Annex 3.

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, 11Hz or 22Hz
Illumination Max
8.1W (@24Vdc)
 Sentence Types (Mag/Gyro
versus
Update Rate)
Hz
Mag
Gyro
Mag Heading Input Ports: -
1
HCHCC
 
Navitron Heading Sensor Coil mounted above or below existing Mag compass
Coil type
HSC1 or HSC2
HCHDG
HEHDT
APHCC
AGHDT
APHDG
 
11
HCHDM
HEHDT
Resolution
0.25°
HCHDG
AGHDT
22
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
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 Bowtruster Interface
and Analogue Steering Interface options)

Cross Track Error Signal Input
(from GPS/Plotter etc. for Track mode use)

NMEA 0183
Sentence types
XX APA
Solid State Solenoid Switching: -
XXAPB
Polarity
Selectable @
Common +VE/-VE
XXRMB
XX XTE
Max Rating
5A (11-40Vdc)
NMEA 0180
(CTE Only)
Panel Alarms: -
Operating Temp Range
-20 to +60 °C
Power Fail
(int / ext supply fail)
Steering Fail
(no rudder response)
Operator Control & Selectors: -
Heading Input
(no heading data)
Yaw
  Alarm Test/Cancel Data Input Fail
(no Track data)
Rudder Autotrim On/Off Off Course
(specified limit exceeded)
Counter Rudder Track On/Off Rudder Limit
(spec'd limit/ROT reached)
Rudder Limit Track HI/LO Resolution Remote
(remote station engaged)
Illumination Off Course Alarm level Alarm Test
(tests all alarms)
Mode Switch +1° / -1° keys (NT921G)
Gyro/Mag Selector Cancel/Confirm keys
(NT990G)
Mechanical
NT921G/990G Control Unit
Width
297mm
Height
176mm
Compass Safe Distance: -
Depth - behind
bezel
110mm
NT921G/990G
Control Unit
0.6m
Weight
3.3Kg


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Click for NT921G & NT990G Control Unit Outline & Mounting Dimensions Click for information on the NT990DSDB Click for information on the NT990DSDB 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 NT920HRC Click for information on the NT920FU Click for information on the NT920NFU Click for information on the NT920WA Click for information on the NT920RAI Click for information on the NT990DSI Click for information on the NT990ASI Click to view image of the NT920RRU