Lun 1794 - Synchro/Resolver to Arinc Converter

The converter is used to convert voltage signal levels from selsyns or resolvers to a digital value corresponding to the angle measured. The digital value is broadcasted on the ARINC bus. 

 The device has three channels (3× - XYZ, 3× - reference phase) and for each channel it is possible to set the type of input signal synchro/resolver. A logical signal informing about the validity is attached to each channel.

The converter is also capable of performing self-diagnostics; it monitors supply voltage level and input signal or its validity. If an error is detected the converter halts and signalizes error.

Typical aplication

LUN1794.3 is successfully instaled on L-410, L-410UVP, JAK40, TU154, An-26 and L39 aircrafts and MI - 24, MI-17 hellicopters.

There are many old synchro or resolver systems there (LUN1205 Electrical gyro horizont, russian GMK gyro among others) serving as sources of analogue signals for LUN1794 output arinc interface is directly connected to safety aircraft systems from Bendix/King - Honeywell (EGPWS, TCAS System).

LUN1794 is also successfully instaled on russian Mi-171, Mi-17V-5 and MI 24 helicopters. There is as the signal source for heading GMK and for roll and pitch AGB-96D, AGB-3K, ARK-15 or ARK-UD.

Systems which may serve as a source of signals

GMK1E Gyro-magnetic compass
AGB-96D Avia horizon
AGB-3K Gyro horizon
AGD1 Artificial horizon
TarSyn H Three-Axis Reference
KEA 130A Encoding altimeter (baro potentiometer)
ARK 15 (АРК15) Automatic Radio Compass
ARK-UD (АРК-УД) Radio Compass
ADC 2000 Fuel and Aerometrical Computer
RDR 2000 Digital Weather Radar
and many others...


Supported Airplanes and helicopters

L-410, L-410UVP, L39, JAK40, TU154, Falcon 50, An-24, An-26, An-28, JAK40, TU154, Dassault Aviation Falcon 50, MIG 21, MIG 29, McDonnell Douglas MD-11
MI-24, MI-171, MI-171S, MI-171Sh, MI-172, MI-17V-5, MI-8, Bell Helicopters 


Variants specification

Inputs Outputs P/N Description
3× Synchro/Resolver
ARINC429 LS/HS LUN1794 Synchro/Resolver to ARINC429
2× Synchro/Resolver
1× Synchro DC (DESYN)
ARINC429 LS/HS LUN1794.1 Synchro/Resolver and Synchro DC to ARINC429
1× Synchro/Resolver
2× 1 phase gyro (ECFR 251)
ARINC429 LS/HS LUN1794.2 Synchro/Resolver and 1phase gyro (ECFR 251) to ARINC429
1× Russian Synchro,
vertical & lateral deviation
OBS selector(Resolver)
LUN1794.3 Converts analog signals of vertical deviation, lateral deviation and signals of vertical and lateral deviation validity from main output of GNS430 unit to format suitable for Russian navigation indicator NPP or similar. More converts OBS(ZK) selection from Russian NPP to GNS OBS Resolver input.
1× Synchro /Resolver
2× Synchro DC (DESYN)
1x GPO Relay
LUN1794.4 Synchro/Resolver and Synchro DC to ARINC429
1× Synchro/Resolver (ARINC407/Russian) ARINC429 LS/HS
1× Synchro/Resolver
output (ARINC407)
LUN1794.5 Synchro/Resolver to ARINC429 and Synchro/Resolver (ARINC407) to connect EHSI.
2× Synchro/Resolver
1× DC
ARINC429 LS/HS LUN1794.6 Synchro/Resolver and DC Baro Correction inHg to ARINC429
3× Synchro/Resolver
3x GPO Relay
LUN1794.7 Synchro/Resolver to ARINC429 and ARINC429 to Runway Markers (GPO Relays)
2× Synchro/Resolver
vertical & lateral deviation & TO/FROM
ARINC429 LS/HS LUN1794.8 Converts analog signals of vertical deviation, lateral deviation and TO/FROM signals.


ARINC429 labels suported

Label Label name
320 Magnetic Heading
321 Drift Angle
324 Pitch Angle
325 Roll Angle
235 Baro Correction inHg
162 ADF Bearing
274 Heading Status
222 Bearing

Technical specification


Type Analog Input Synchro (XYZ) or Resolver (SIN/COS)
Number of Channels Three Fully Independent
Analog Input 3× synchro/resolver,
3× 26V/36V 400 Hz
3× reference signal, 26V/36V 400 Hz (ARINC 407 or Russian)
Digital Input 3× flag input - opto isolated
Communication interface Arinc 429
RS 232 for service only


General parameters

Input Impedance 20 kOhm, f=400Hz
Conversion Accuracy ±0,3 °
Power supply 14...32 V DC
Power consumption 5,0 W
Operating temperature range -55 - 70 °C
Storage temperature -55 - 85 °C
Humidity max. 95 %
Connector MIL-37, CAN 9
Dimensions 206 × 70 × 100 mm
Weight 1500 g


Block diagram

lun1794 block diagram



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