"Frank" wrote in message
...
Hi group,

I have a question concerning the update rate of a SeaTalk bus.

I have a GPS ( NMEA ), a ST60 tridata ( SeaTalk ) and a SeaTalk Autopilot.

In order to exchange Data between NMEA - Seatalk I built a
single chip computer ( Atmega32 ).

Ok - now i can translate NMEA Sentences to SeaTalk datagrams and
vice versa.
The GPS sends its information about ever two seconds.
But how often should i sent data to the SeaTalk bus.

If you are able to read from the Seatalk bus, you can see how often other
instruments send their data, right?

My boat is somewhere far away in in winter storage. So currently
i can't just go to the boat and check myself.

Currently my software just sends updates to seatalk, whenever
NMEA data changes ( And vice versa ).

I would send Seatalk data for every received NMEA sentence. Otherwise you
would never know when the NMEA source has stopped sending (faulty hardware).

But when the boat stands still, the speed or position
never changes. This can't be correct - i guess.

I find that hard to believe. I have a GPS sitting on my desk and the speed
and bearing constantly vary, caused by the random 'noise' on a GPS fix.

Again, translate every sentence when it comes in and transmit it. Since
Seatalk is binary, the datagrams are much shorter that NMEA sentences, so
your bandwidth is higher.

Meindert