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LH2 to LH3, NEMA data missing
05-15-19, 03:43 PM
Post: #1
LH2 to LH3, NEMA data missing
I am upgrading from an a128 running LH2 19.03 and now have an Axiom 12 w/ 3.9.46. I have a Chetco Digital SeaGuage G2 that was providing RPM, battery voltage, oil pressure and coolant temp on the a128 and was up and running.

The only thing I have now is the tachometers and incorrect display of the coolant temp (reads 150 deg f and doesn’t change). Was there an update to the PGN files from LH2->LH3?

Or is there something else going on? How can I see the NEMA data on the network. Seems I could see this on the a128/LH2.
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05-15-19, 09:13 PM
Post: #2
RE: LH2 to LH3, NEMA data missing
Hello dtfeld,

The NMEA2000 engine data that the MFDs read hasn't changed between LH2 and LH3. There are two standard messages that carry this data, 127488 (Engine Parameters, Rapid Update) and 127489 (Engine Parameters, Dynamic.) Both generations of display read the data within these messages in the same way. However, that's not tquite the whole story.

The most common problem with engine data is with incorrect Instance numbers, which I've described in some detail here. I'd suggest giving that post a read and if in doubt, following the [url=]instructions here[/ur] to record the NMEA2000 data on your MFD and send it in to me for analysis.

Regarding the voltage reading specifically: there are several different places where voltage can be measured:
  • Battery voltage, which is expected to be measured at the battery by a charger or similar, and is transmitted in the Battery Status message, 127508
  • Alternator voltage, which is expected to be measured by the engine and is output in 127489.
  • Product supply voltage, measured within an Axiom MFD and not transmitted over NMEA2000
Depending on what our SeaGauge is outputting, you'll need to look at a different data item on the Axiom. If the SeaGauge is outputting its measurement as Battery Voltage (Instance 0, see the above link for details) then you need to set up a Battery Voltage 1 data item on the Axiom in order to see it. If, on the other hand, the SeaGauge is outputting Alternator Voltage in 127489 then it's the Alternator Voltage data item that you need to set it to display. What is the name/title of the data item that you're looking at?


Raymarine since 1999.
Interests: Diagnosis of problems in sonar/fishfinders, NMEA2000, ethernet comms, autopilots, thermal cameras
Location: Sydney, Australia.

Please don't PM me asking for direct support, please ask a public question instead so that others can see the question and answer. Forum posts will always be answered before PM requests.
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