# Engine Hour meter with NMEA output?

Discussion in 'Boat Electronics' started by Glenn Ashmore, Apr 7, 2005.

1. ### Glenn AshmoreGuest

Almost finished with my microcontroller fuel based management system and
stil have the USART pins free. I am storing the gallons transferred in
EEPROM but it would be nice to have a time base to store with them. If I
had the engine hours for each transfer I could calculate average fuel
consumption and a lot of other interesting tidbits. Anyone know of an hour
meter that has digital output?

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com

2. ### Bert van den BergGuest

The CruzPro RH30 and RH110 digital RPM/engine hours gauge outputs a
proprietary NMEA sentence that contains:

RH30/RH110 Digital RPM/Engine hours gauge sample sentence:

Parse as:
\$PBVE, B E AA ADAA AB FKBC IIBD AGOO AB AAAA AD AAAA OIAC AA
ON FMAK CA AD AAAA HG

B = Product Code (B= RH30)
E = Software Version
AA = Spare NMV Byte (Ignore)
AB = Ignore
FKBC = Maximum RPM seen from last reset
IIBD = High RPM Alarm value
AGOO = Clock Speed Calibration #
AB = Backlight Level
AAAA = Maintenance count-down alarm
AAAA = Engine Hours
OIAC = RPM Calibration number
AA = Mode
AN = Non voltatile memory checksum
FMAK = RPM
CA = Elapsed Seconds
AAAA = Elapsed Hours
HG = NMEA Sentence checksum

Where A=0, B=1, C=2, ... , O=14, P=15

Decode RPM as:
FMAK = 16*F + M + 4096*A + 256*K
FMAK = 16*5 + 12 + 4096*0 +256*10
FMAK = 2652 RPM

**************************************************************

Best Regards,

Bert van den Berg
CruzPro Ltd.
www.cruzpro.com