I have had this problem in the past and have found that by adding ferrite rings to the cable and also reducing the baud rate can help eliminate these errors. Also, keeping the data cable routed away from sources of RF noise, such as USB power adapters, the Davis power adapter and also wifi/bluetooth adapters if you use them.
On Monday, 19 December 2016 19:43:27 UTC, Ford Donald wrote: > > I'm running weewx latest on a series 3 raspberrypi, using Davis Weather > Envoy (fw 3.15) to record and transfer data. Connection is USB, using the > factory cable with added iron chokes at both ends. Station is VP2+ wireless. > > Booting the RPi up works fine and weewx starts normally. But, 100% of the > time the data collection fails to start, usually with this: > > Dec 19 13:33:00 raspi-weather weewx[1548]: engine: Starting up weewx > version 3.6.2 > Dec 19 13:33:00 raspi-weather weewx[1548]: engine: Clock error is -24.96 > seconds (positive is fast) > Dec 19 13:33:00 raspi-weather weewx[1548]: vantage: Clock set to > 2016-12-19 13:33:01 CST (1482175981) > Dec 19 13:33:07 raspi-weather weewx[1548]: vantage: DMPAFT try #1; error: > Time out in get_data_with_crc16 > Dec 19 13:33:20 raspi-weather weewx[1548]: vantage: DMPAFT try #2; error: > Time out in get_data_with_crc16 > Dec 19 13:33:32 raspi-weather weewx[1548]: vantage: DMPAFT try #3; error: > Time out in get_data_with_crc16 > Dec 19 13:33:44 raspi-weather weewx[1548]: vantage: DMPAFT try #4; error: > Time out in get_data_with_crc16 > Dec 19 13:33:44 raspi-weather weewx[1548]: vantage: DMPAFT max tries (4) > exceeded. > Dec 19 13:33:44 raspi-weather weewx[1548]: engine: Caught WeeWxIOError: > Max tries exceeded while getting archive data. > Dec 19 13:33:44 raspi-weather weewx[1548]: **** Waiting 60 seconds then > retrying... > > I've followed the guidance online about changing cables and adding chokes. > The original Envoy cable tends to be the best. Envoy is powered by line > power, so battery power isn't an issue. > > I can usually get things going eventually if I stop and start weewx > repeatedly until the errors clear and WUnderground rapidfire starts to > flow. If I leave it along after that it does pretty well. But, security > patches come along and after patching this process starts again. > > Otherwise, normal operation looks like this: > > Dec 19 13:41:05 raspi-weather weewx[1548]: engine: Starting main packet > loop. > Dec 19 13:41:10 raspi-weather weewx[1548]: vantage: LOOP try #1; error: > Expected to read 99 chars; got 0 instead > > Thanks for reading, > Ford > > > -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
