PGN 126992 SystemTime about nmea2000

[ttlappalainen]

No. The fields are sent to bus in right order. In interface they are ordered in order of necessity to have time source at the end so that it can have default value and does not need to provide by caller. I do not know how you have 15 on time source, since known value range is 0-5. Actually I think that NMEA reader should show "Not Available".

And yes, there is small erro in code, which I'll fix on next version. I do provide to reserved 0 instead of 0xf. And on listening TimeSource may get crazy values, since it does not have filter xx & 0xf.

[usauerbrey]

Besides the order, does the NMEAReader do a conversation? If not, it shows Date an Time as 04/10/2017 and not as
SystemDate Days since 1970-01-01
SystemTime seconds since midnight
so I am unclear

[ttlappalainen]

NMEA Reader does the conversion. And SystemTime is UTC.

You can find example NMEA0183ToN2k under https://github.com/ttlappalainen/NMEA0183/tree/master/Examples/NMEA0183ToN2k how I use it. RMC message provides same value, so I do not need any time.h. I have also code for converting DaysSince1970 to current date.

[usauerbrey]

Hi Timo

Thanks very much, it is always a problem with monitoring, do they give raw data or already processed data.

Uwe

[usauerbrey]

Add question, where can I find the code for converting DaysSince1970 to current date?

[ttlappalainen]

Look NMEA0183Msg.cpp there is:

unsigned long tNMEA0183Msg::DaysToNMEA0183Date(unsigned long val) {
  if ( val!=NMEA0183UInt32NA  ) {
    tmElements_t tm;
    time_t t=val*SECS_PER_DAY; //daysToTime_t((val));
    breakTime(t, tm);
    val=tm.Day*10000+(tm.Month)*100+(tm.Year+1970-2000);
  }
  
  return val;
}

It converts DaysSince1970 to value ddmmyy used in NMEA0183. It uses timelib.h, which also have define for tmYearToY2k(tm.Year), which I could have use instead of (tm.Year+1970-2000). Write your own function, which returns date from tm in format you like to have.