Solving Typical NMEA 0183 Network Issues

Transcription

1 Solving Typical NMEA 0183 Network Issues

2 NMEA 0183 Network Issues Ground loops and how to avoid them Differences between v.1 and v.2 (& above) Connecting low-drive Talkers to multiple Listeners Only one Talker / Unidirectional Network power requirements can be significant Data loops What they are and how to avoid them! Limited bandwidth Slow transfer rates

3 Ground Loops: EMI & PD

4 Ground Loop solution: OPTO-Isolation Electrical signal is converted to light and then back to an electrical signal on other side No electrical current flows between the input and output sides of the OPTO The input is powered by the Talker and the output is powered by the Listener

5 NMEA 0183 Version 1 and Version 2 Version 1 Version 2

6 Isolation & low-drive solution: ISO-Drive TM A ground-breaking RS422/RS232 output technology available across the Actisense NMEA 0183 range Each isolated output can float from system ground (and any other output) up to 1500 volts Safely interface PC equipment to marine data buses Powerful drive capability meets all NMEA 0183 version specifications (1 through 4) Electrical spike, over-voltage & short-circuit protection Low power consumption, much more efficient than power hungry battery power isolators

7 Isolation and Drive Solutions Buffers the signal from an NMEA 0183 Talker in to six identical, isolated outputs Adds isolation to non-isolated Listeners to prevent ground loops Single cable used to both power the NMEA 0183 Talker and connect data to input Input is NMEA 0183, RS422, RS232 and RS485 Talker compatible Each outputs is NMEA 0183, RS422, RS232 and RS485 Listener compatible

8 Connect Multiple Talkers Together NDC-4 (Standard) NDC-4-AIS NDC-4-ASW NDC-4-USB NDC-4-AIS-USB

9 Single Talker & Isolation solution: NMEA Multiplexer & NMEA Buffer

10 Data loop solution: Data Filtering Data loops typically occur when an NMEA 0183 device is connected to both the input and output of an NMEA 0183 Multiplexer Data bandwidth is consumed rapidly, causing data to be dropped randomly The solution is to use an NMEA Multiplexer that offers sentence filtering to break the data loop and restore normal data flow e.g. Chart Plotter

11 Any questions?

12 NMEA 2000 Possibilities & Limitations

13 Introduction Owen Vachell Tech Support Engineer Based in the United Kingdom Over 20 years specialist experience NMEA Specialists, active in all NMEA Standard Committees Award winning products Sell direct in to 34 countries

14 Topics Covered Understanding NMEA 2000 networks Minimum requirements Limitations Physical layer Data layer Certification PC integration Comparison with NMEA 0183 Hybrid networks

15 Understanding NMEA 2000 networks

16 Minimum network requirements 1 x Power-T 2 x Terminating Resistors 2 x T-Pieces (one per connected device) 2 x NMEA 2000 certified devices

17 Network limitations

18 Physical layer Proven and robust cables & connectors 12V power supplied to all low-powered devices directly from the bus Up to 2 legs to distribute the load evenly Reduces amount of cabling Standardised wiring colours Simple plug & play connectivity Easily expandable without power interruptions None of the physical layer issues of NMEA 0183 networks are present in NMEA 2000

19 Network power Power provided to the backbone from one or two sources, standard or isolated 9-16 VDC today, 9-32 VDC in future All low-powered devices (< 1 Amp) take power directly from the backbone

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22 Data Layer Binary 250k Baud Bi-directional data transfer Prioritised data transmission 100% of the bandwidth is available (no loss due to collisions) Send large amounts of data, quickly PGN information available from PGN data field information contained in Appendix B

23 NMEA 2000 Certification Any device claiming NMEA 2000 Approved must be certified, including its cables and connectors Certification tool provided by the NMEA Ensures devices can safely co-exist on the same network Be careful if using devices that state NMEA 2000 Compatible or Works With

24 Safely connecting a PC to an NMEA network

25 Connecting to: NMEA 2000 No standard method for sharing NMEA 2000 / CAN data over a serial link to a PC Each PC software developer is required to modify their application to work with the chosen NMEA 2000 PC interface Isolation between all devices is mandatory NMEA 2000 certification is not currently mandatory for software PGN messages are binary, making them unreadable; NMEA Reader and N2KAnalyser viewers can display each message and its data fields

26 NMEA 2000 to: Safe isolated USB Two NMEA 2000 PC Gateways are available for connection to an NMEA 2000 network via USB: Actisense NGT-1-USB & Maretron USB100 USB100 is primarily only compatible with Maretron software NGT-1-USB is the leading industry solution supported by over 40 software developers and 3 hardware manufacturers Ideal NMEA 2000 diagnostic tool when used with NMEA Reader / N2KAnalyser

27 NMEA 2000 to: NMEA 2000 software Actisense NGT-1-USB Maretron USB100 N2KAnalyser N2KView Coastal Explorer Actisense NGT-1-USB NMEA Reader EBL Reader Toolkit Coastal Explorer Expedition Fugawi Marine 5 MacENC MaxSea TimeZero Nobeltec Ad, VNS, TZ PC Plotter PolarView Smart Skipper... and more

28 Tool and techniques for diagnosing NMEA networks

29 Every network has issues

30 Hardware diagnostic tools

31 NMEA diagnostics: NMEA Reader View all NMEA 0183 or NMEA 2000 data See the devices on an NMEA 2000 network Analyse NMEA data in realtime Log function allows data to be saved to file Change System, Device & PGN/Data instances Freely available

32 NMEA diagnostics: EBL Reader Electronic Binary Log Reader shows log files saved by NMEA Reader Conduct basic diagnostics Analyse NMEA data in extreme detail Find time intervals & missing sequences Freely available N2KAnalyzer shares some of these features

33 Network comparison: NMEA 0183 Tried and Tested, widespread use 5 Channel Multiplexer required 6 Channel Amplifier / Buffer required Easy to create ground loops Difficult to document Difficult to expand

34 Network comparison: NMEA 2000

35 Network comparison: Space reduction NMEA 0183 NMEA 2000 Images courtesy of NMEA

36 Network comparison: Labour reduction NMEA 0183 NMEA 2000 Image courtesy of NMEA & Panbo

37 Network comparison: Weight & price reduction NMEA devices requiring 250 metres of 6 core cable = 1000 / 1400 (@ 4/m) = 20 Kg NMEA devices requiring 40 metres of 4 core cable and 15 T-pieces = 565 / 790 (5m x 1, 2m x 8, 1m x 19) = 5 Kg Images courtesy of NMEA

38 Creating reliable hybrid NMEA networks

39 Generation incompatibilities NMEA 0183 ASCII $SDDBT,22.7,f,06.9,M,03.8,F*35 One Talker 4800 baud (38400 for AIS) Slow transfer rates NMEA 2000 Binary PGNs PGN , data 6E-B E0-FC-FF Bi-directional 250k baud Multi/Fast packet for faster transfer rates

40 Data conversion limitations NMEA 0183 v4.01 (June 2012) 148 sentences data fields Very limited engine data (RPM) Limited sensor data (e.g. tank level, battery) Very basic alarm data NMEA 2000 Ed 3.10, Db v2.100 (Feb 2015) 163 PGN messages 1569 data fields Complete set of Engine data Extensive sensor data Recently added extensive alarm data

41 NMEA 2000 Gateways Two main NMEA 2000 Gateways are available for connection to an NMEA 0183 device: Actisense NGW-1 & Simrad AT10 Simrad AT10 perform a fixed set of conversions Actisense NGW-1 is field configurable Actisense NGW-1 works seamlessly with Raymarine s SeaTalkNG networks Both are NMEA 2000 certified

42 Upgrade method 1: Multiplex & convert

43 Upgrade method 2: Direct conversion

44 NMEA 2000 to: NMEA 0183 software Any NMEA 0183 capable software, for example: Actisense NGW-1-USB Coastal Explorer Expedition Fugawi MacENC MaxSea Nobeltec OpenCPN PC Plotter PolarView SeaPro Smart Skipper Software On Board WinGPS and more

45 Any questions?

46 Thank you