Aids to Navigation monitoring data

Introduction/Additional information:

Monitoring the status of lighthouse equipment and buoys; reliability, maintenance, availability

Permitted as from:

15/01/2009

Registrant:

UK Trinity House

Physical link:

AIS

Message number (0=VDES-VDE):

DAC or VPFI:

235

FI / Message ID:

Technical point of contact:

Alan Stuwart

State:

in force

Number of slots (max):

Last modified:

29/01/2021 - 23:18

Reporting Rate:

Varies, depending on the type of AtoN (1-10 minutes)

The interval between the transmission of these messages will be synchronized with message 21, although not necessarily at the same reporting rate. If Message 21 is not used at a particular site, then the reporting interval should be selected to minimise the power requirement of the transponder, whilst still providing enough data to enable meaningful diagnostic analysis.

Used by:

UK Trinity House

Commissioners of Irish Lights

Northern Lighthouse Board

Details:

Parameter	Number of bits	Description
Message ID	6	Identifier for this message 6; always 6.
Repeat Indicator	2	Used by the repeater to indicate how many times a message has been repeated. 0 - 3; default = 0; 3 = do not repeat any more.
Source ID	30	MMSI number of source Unit
Sequence Number	2	0 - 3
Destination ID	30	MMSI number of destination Unit.
Retransmit Flag	1	Retransmit Flag should be set upon retransmission: 0 = no retransmission = default 1 = retransmitted.
Spare	1	Not used. Should be zero.
DAC	10	Destination Area Code. Default: 235 (UK & NI) or 250 (ROI)
FI	6	Function Identifier Default: 10 for this GLA standard message
Analogue (internal)	10	0.05- 36V 0.05V step Supply voltage to AIS Unit 0 - Not Used
Analogue (external - from hardware analogue input No 1	10	0.05 - 36V 0.05V step 0 - Not Used
Analogue (external - from hardware analogue input No 2	10	0.05 - 36V 0.05V step 0 - Not Used
Status Bits 0 / 1 (internal - same as the 5 LSBs of status bits from Message type 21)	5	4 \ / 00 - no RACON installed; 01 - RACON not monitored 3 / \ 10 - RACON operational; 11 - RACON ERROR 2 \ / 00 - no light or no monitoring; 01 - Light ON 1 / \ 10 - Light OFF; 11 - Light ERROR 0 0 - Good Health, 1 - Alarm
Status Bits 0 / 1 (external - derived from hardware digital inputs)	8	7 Digital Input Off/ / On : : 0 Digital Input Off/ / On
Off Position Status	1	Off position or On position 0: On position 1: Off position
Spare	4	For future use. Should be zero.
TOTAL OF BITS.	136	Occupies 1 slot.

How portrayed:

Text and graphical (at shore-based monitoring centres, buoy tending vessels) - uses ICAN “Bespoke” dedicated graphic software for display - shows trending over time; alarm dispatching, etc.