NMEA2000 Library  0.1
Library to handle NMEA 2000 Communication written in C++
Additional Information about NMEA2000

Table of Contents

NAME

On NMEA2000 NAME (written all capital) means data defined by device information. Since device information will be sent by PGN 60928, NAME is also 8 byte content of than message. NAME can be used to identify devices sending some information. For this reason it is important that NAME is unique for all devices on the bus.

Normally unique number and manufacturer code within device information should be enough to define unique device. Some manufactures does not do that and their devices may require modification for device instance when same devices appears on the bus.

Safest way to fullfill unique NAME requirement is to keep unique number unique. For commercial production that requires some kind of register for manufactured devices.

On library you set device information by using function tNMEA2000::SetDeviceInformation and if necessary with function tNMEA2000::SetDeviceInformationInstances.

Address claiming

NMEA2000 bus can have maximum 252 devices. Each device will get device source address (0-251), which can be predefined on device start, but may be changed by address claiming at any time.

On start device starts address claiming using previously saved source address by sending its NAME to the bus by using message ISO address claim PGN 60928. If there is no other device using same source address, device can start normal operation after 250 ms delay. If there is another device using same address there are two possible cases.

  1. Other device NAME has lower priority, so it will increment its own address and start address claiming. This device can keep its source address.
  2. Other device NAME has higher priority and responds with ISO address claim. This device will increment its source address and start address claiming again with new address.

If bus is full of devices, devices with lowest priority will get source address 254 and they can not send anything to bus.

Library takes care of address claiming and required silence delay automatically. To get information possible source address changes, use funtion tNMEA2000::ReadResetAddressChanged().

NMEA2000 instances

Instances are used in an NMEA 2000 network to identify multiple similar products connected on the same network.

As an example, take a system with two battery monitors (one for the main battery bank, and another for the hydraulic-thruster bank) and also a Quattro inverter/charger. All three of those devices will send their battery voltage measurements out on the N2K network. For the displays to show these values at the right place, they need to know which voltage belongs to what battery. That is what instances are for.

Different types of instances

There are various types of instances: Device instance, Data instance and System instance. Device and System instance is stored in tNMEA2000::tDeviceInformation and so they are also part of NAME. See also tNMEA2000::SetDeviceInformationInstances.

Device instance

The device instance is sent in PGN 60928, ISO Address Claim, as a combined field of Device Instance Lower (ISO ECU Instance) and Device Instance Upper (ISO Function Instance). The Device instance is e.g., used by Victron chargers (Skylla-i/-IP44, VE.Can MPPTs) to configure them in the same group and synchronize them.

Data instances

These instances belong to data on the bus (e.g., Battery Instance, DC Detailed Instance, Switch bank instance, etc.) and are embedded in the different PGN’s. For changing these instances through a complex write, PGN 126208, Complex Request Group Function Code 5, write fields.

System instance

The system instance is also sent in PGN 60928, field 8. System instance indicates device occurence in other like redundant or parallel NMEA2000 networks. For small and simple vessels this is always 0.

See also

SID

The sequence identifier field is used to tie different PGNs data together to same sampling or calculation time. In other words same SID in different PGNs sent by same device defines that values on PGN:s has been sampled or calculated at same time. Devices reading those messages can use in calculations PGNs data provided with same SID and get more accurate results.

For example, the GPS200 will transmit identical SIDs for 126992 (System Time), 128259 (Speed), 129026 (COG and SOG, Rapid Update), 129029 (GNSS Position Data), 129539 (GNSS DOPs), and 129540 (GNSS Satellites in View) to indicate that the readings are linked together (i.e., the data from each PGN was taken at the same time although they are reported at slightly different times).

E.g., with temperature data I do not see any use for SID. Temperature changes are normally anyway slow and 1.5-2 s difference on sampling does not have meaningfull effect. I would also think that there is no device using SID for temperature, pressure and humidity data.

On sending in most cases you can use just 0xff for SID. On receiving you can normally just forget it.

If you like to use SID, you have to increase value synchronized with sampling and sending. SID value has to be on range 0-252. 255 (0xff) means data not available and 253-254 are reserved. So use it e.g., with code

If you e.g., sample your multisensor every 2 s,
but PGNs will be sent every 1 s you can increase SID after each sampling and there would be
2 sends having same SID indicating that they have been sampled at same time.
If you instead sample faster than send, you have to increase SID after all related messages
has been sent. It would be even more complex if your devices a lot different messages and their
sampling is grouped and requires different SID. Then you have to also take care that messages
which are not linked to each other never has same SID.
If you use multitasking system, you should also lock data
during sampling and sending so that they would not change during task. If you e.g.,
have task sending sensor values from some kind of globals, both task should use some
data locking system:
Sampling task:
```shell
SampleSensors(Sensor1,Sensor2);
LockSend();
Sensor1Out=Sensor1;
Sensor2Out=Sensor2;
SensorsSID++; if ( SensorsSID>252 ) SensorsSID=0;
ReleaseSend();

Sending task:

LockSend();
double S1=Sensor1Out;
double S2=Sensor2Out;
SID=SensorsSID;
ReleaseSend();
SendSensorsData(SID,S1,S2);

Manufacturer Code

The Manufacturer Code is part of the NAME (see tNMEA2000::tDeviceInformation). Manufacturer code is mandatory for each NMEA2000 device and it has to be requested from NMEA organization.

Note that NMEA2000 devices does not have way to request manufacturer name. Manufacturer code is link to hardcoded name. So if you have old MFD and sersor from new manufacturer, sensor will be listed with name "unknown manufacturer".

Some manufacturers hardcodes which manufacturer sensors they accept. So in case e.g., MFD document claims to support e.g., PGN 130316, but sensor data will not be shown or not shown properly, check your MFD manufacturer that your sensor manufacturer is listed in their database. As opposite if you make device for your own vessel only, you can setup your device to use accepted manufacturer code.

List of registered manufacturer codes

NMEA2000 certification

I have advertised library to be certification ready. There are some functionalities left for developer, since there is no common way do that. Good example is saving possibly changed source address or device/system instances. It is developer responsibility to choose method for saving. It can be e.g., EEPROM, file, flash. To fullfill all certification requirements you have to add some functionality.

For commercial certified devices you need also (prices at 2024 are for members):

  • Join as member to NMEA organization - new member 475 $, yearly renewal 300 $.
  • Request Manufacturer Code from NMEA organization - 1200 $.
  • Request ProductCode from NMEA organization - 450 $.
  • Run certification tests for you device. For that you need specific certification tool. You can ask help from me. Costs depends of certification test provider - I know some providers. Costs 500 $ - 2000 $.
  • Certification verification - 850 $.

So total costs for certified device for new member is about 4000 $.

Relation between CAN ID and NMEA2000

The SAE J1939 protocol requires a specific format for the CAN message’s identifer. The ID can consist of 11 bits, or optionally 29 bits in the extended format. At NMEA2000 only the extended format ist supported.

  • Priority (28-26)- establishes the arbitration priority, highest priority being 0 and lowest is seven
  • EDP (25) - Extended Data Page: combined with DP to identify different message definitions
  • DP (24) - Data Page: J1939 set to Page 0, Page 1 for NMEA2000
  • PDU Format (23-16) - helps to define the parameter group the message belongs in. Distinguishes what type of data is being sent
  • PDU Specific (15-8) - the address of the message’s destination device
  • Source Address (7-0) - the address of the message’s source device
See also
J1939 PGN vs. 29-Bit CAN ID - Online Converter

List of registered manufacturer codes

Code Manufacturer name
78 Fw Murphy
80 Twin Disc
85 Kohler Power Systems
88 Hemisphere
116 BEP Marine
135 Airmar
137 Maretron
140 Lowrance
144 Mercury Marine
147 Nautibus Electronic Gmbh
148 Blue Water Data
154 Westerbeke
161 Offshore Systems UK
163 Evinrude/Brp Bombardier
165 CPAC Systems Ab
168 Xantrex Technology
172 Yanmar Marine
174 Ab Volvo/Volvo Penta
176 Carling Technologies
185 Beede Electrical
192 Floscan Instrument Co., Inc.
193 Nobeltec
198 Mystic Valley Communications
199 Actia Corporation
201 Disenos Y Technologia
211 Digital Switching Systems
215 Xintex/Atena
224 Emmi Network
228 Zf Marine Electronics
229 Garmin
233 Yacht Monitoring Solutions
235 Sailormade Marine Telemetry
243 Eride
257 Honda Motor Company
272 Groco
273 Actisense
274 Amphenol Ltw Technology
275 Navico
283 Hamilton Jet
285 Sea Recovery
286 Coelmo Srl Italy
295 BEP Marine
299 Garmin
304 Trigentic/EmpirBus
305 Novatel
306 Sleipner Motor As
307 Mbw Technologies
315 ICOM
328 Qwerty
329 Dief
341 Böning Automationstechnologie GmbH
345 Korea Maritime University
351 Thrane And Thrane
355 Mastervolt
356 Fischer Panda Generators
358 Victron Energy
370 Rolls Royce Marine
373 Electronic Design
374 Northern Lights
378 Glendinning
381 B&G
384 Rose Point Navigation Systems
385 Johnson Outdoors Marine Electronics
394 Capi 2
396 Beyond Measure
400 Livorsi Marine
404 ComNav
419 Fusion Electronics
421 Standard Horizon
422 True Heading
426 Egersund Marine Electronics As
427 Em-Trak Marine Electronics Ltd
431 Tohatsu Co Jp
437 Digital Yacht
438 Comar Systems Limited
440 Cummins
443 VDO
451 Parker Hannifin
459 Alltek Marine Electronics Corp
460 San Giorgio S.E.I.N.
466 Veethree Electronics
467 Humminbird Marine Electronics
470 SI-TEX Marine Electronics
471 Sea Cross Marine Ab
475 GME/Standard Communications
476 Humminbird Marine Electronics
478 Ocean Sat Bv
481 Chetco Digitial Instruments
493 Watcheye
499 Lcj Capteurs
502 Attwood Marine
503 Naviop S.R.L.
504 Vesper Marine
510 Marinesoft Co. LTD
517 NoLand Engineering
518 Transas USA
529 National Instruments Korea
532 Onwa Marine
540 Webasto
571 Marinecraft Co.
573 McMurdo Group
578 Advansea
579 KVH
580 San Jose Technology
583 Yacht Control
586 Suzuki Motor Corporation
591 USCG
595 ShipModul
600 Aquatic AV
605 Aventics GmbH
606 Intellian
612 SamwonIT
614 Arlt Tecnologies
637 Bavaria Yacts
641 Diverse Yacht Services
644 KUS Manufacturer
645 Garmin
658 Shenzhen Jiuzhou Himunication
688 Rockford Corporation
704 JL Audio
715 Autonnic
717 Yacht Devices
734 REAP Systems
735 Au Electronics Group
739 LxNav
740 JL Audio
743 DaeMyung Elevator
744 Woosung
773 Clarion US
776 HMI Systems
777 Ocean Signal
778 Seekeeper
781 Poly Planar
785 Fischer Panda DE
795 Broyda Industries
796 Canadian Automotive
797 Tides Marine
798 Lumishore
799 Still Water Designs and Audto
802 SPBI SA Ets BJTechnologie
803 Gill Sensors
811 Blue Water Desalination
815 Flir Systems
824 Undheim Systems
838 TeamSurv
844 Fell Marine
847 Oceanvolt
862 Prospec
868 Data Panel Corp
890 L3 Technologies Maritime Systems
894 Rhodan Marine Systems
896 Nexfour Solutions
905 ASA Electronics
909 Marines Co (South Korea)
911 Nautic-On, A Brunswick Company
930 Ecotronix Corp
944 Zonisa Marine
951 Exor International S.p.A.
962 Timbolier Industries
968 Cox Powertrain
969 Blue Sea
981 Kobelt
1008 Lintest SmartBoat
1011 Soundmax
1020 Onyx Marine Automation s.r.l
1021 Entratech
1022 ITC Inc.
1023 PEAK-System Technik GmbH
1029 The Marine Guardian LLC
1034 Siren Marine
1047 Sonic Corporation
1051 ProNav
1053 Stillwater Designs / Kicker
1059 Boatrax
1062 ComNav
1065 CALYPSO Instruments
1066 Spot Zero Water
1070 Quick-teck Electronics Ltd
1075 Uniden America
1083 Nauticoncept
1084 Shadow-Caster LED lighting LLC
1088 E-T-A Circuit Breakers
1092 Scheiber
1095 Wetsounds
1140 Across Ocean Systems Ltd.
1305 Dragonfly Energy
1850 Teleflex
1851 Raymarine
1852 Navionics
1853 Japan Radio Co
1854 Northstar Technologies
1855 Furuno
1856 Trimble
1857 Simrad - Navico
1858 Litton
1859 Kvasar Ab
1860 Mmp
1861 Vector Cantech
1862 Sanshin Industries/Yamaha Marine
1863 Faria Instruments