2017-06-10, 05:57 AM
Just to close this thread out for anyone interested ....
I traced the errand characters to definitively come from the NMEA 0183 bus. Several NMEA0183 to USB converters were tested. Two turned out to be defective but two others worked fine and had occasional corrupted characters. The corruption was also present on a different computer and also present with the NMEA line terminated with a 150 ohm resistor. I am unable to trace the issue further and to the source as I do not have anything to check out the Seatalk bus. The characters could be generated by one of three instruments on the Seatalk bus feeding the chartplotter or the chartplotter (Raymarine E80) could be generating them.
As mentioned before, the corrupted characters were not allowed under NMEA 0183 specs and they should not be able to crash the signalK server. Sailoog will address the issue with the signalK developer and I hope that data validation on the input to signalK can eliminate the crashing in the future.
I traced the errand characters to definitively come from the NMEA 0183 bus. Several NMEA0183 to USB converters were tested. Two turned out to be defective but two others worked fine and had occasional corrupted characters. The corruption was also present on a different computer and also present with the NMEA line terminated with a 150 ohm resistor. I am unable to trace the issue further and to the source as I do not have anything to check out the Seatalk bus. The characters could be generated by one of three instruments on the Seatalk bus feeding the chartplotter or the chartplotter (Raymarine E80) could be generating them.
As mentioned before, the corrupted characters were not allowed under NMEA 0183 specs and they should not be able to crash the signalK server. Sailoog will address the issue with the signalK developer and I hope that data validation on the input to signalK can eliminate the crashing in the future.