Cumulus Support

CMX 3.6.6 3082 seems to be incrementing the values for barometric pressure in wxnow.txt, It appears to clime and reset. Restarting CMX doesn't seem to sort it.
CMX currently reads pressure as 1013.61mb (http://www.duncreggan.net/cumulusmx/index.htm)

wxnow.txt extracts over a few minutes:
Jun 02 2020 23:14
359/003g008t062r000p000P000h59b10434
Jun 02 2020 23:17
356/004g008t062r000p000P000h58b10549
Jun 02 2020 23:19
355/004g008t062r000p000P000h59b10627
Jun 02 2020 23:22
353/003g005t062r000p000P000h58b10746
Jun 02 2020 23:25
348/003g005t062r000p000P000h59b10826

I noticed this while checking the outputs to CWOP from my APRS station which directly reads the wxnow.txt.
You can see the pattern of rogue readings here (column headings first), before i killed the upload:
time (UTC), temp C, wind direction, speed KPH, gust KPH, rain 1hr cm, rain 24hr cm, rain mn cm, humidity %, barometer mb
20200602214921 16 355 3.2 6.4 0.00 0.00 0.00 60 1082.8
20200602214801 16 353 3.2 6.4 0.00 0.00 0.00 60 1070.9
20200602214429 16 355 3.2 6.4 0.00 0.00 0.00 61 1063.0
20200602214323 16 355 3.2 6.4 0.00 0.00 0.00 61 1059.1
20200602211601 17 324 1.6 3.2 0.00 0.00 0.00 59 1013.8
20200602210103 17 324 3.2 4.8 0.00 0.00 0.00 57 1013.8
20200602204603 18 324 3.2 4.8 0.00 0.00 0.00 56 1013.9
20200602203102 18 323 1.6 3.2 0.00 0.00 0.00 54 1014.0
20200602201602 19 324 3.2 6.4 0.00 0.00 0.00 54 1014.1
20200602200102 19 325 4.8 9.7 0.00 0.00 0.00 52 1014.2
20200602194603 20 319 6.4 11.3 0.00 0.00 0.00 51 1014.3
20200602193103 20 313 6.4 14.5 0.00 0.00 0.00 50 1014.3
20200602191602 20 322 8.0 14.5 0.00 0.00 0.00 50 1014.5
20200602190102 20 318 9.7 17.7 0.00 0.00 0.00 49 1014.6
20200602181603 21 325 9.7 17.7 0.00 0.00 0.00 47 1064.3
20200602180102 22 316 12.9 20.9 0.00 0.00 0.00 46 1015.0
20200602174602 22 311 14.5 20.9 0.00 0.00 0.00 45 1015.2
20200602173103 23 316 14.5 22.5 0.00 0.00 0.00 44 1015.4
20200602171603 23 320 14.5 27.4 0.00 0.00 0.00 42 1015.5
20200602170102 23 330 14.5 27.4 0.00 0.00 0.00 43 1015.6
20200602163101 24 323 14.5 25.7 0.00 0.00 0.00 33 1015.7
20200602161603 23 331 14.5 22.5 0.00 0.00 0.00 40 1015.9
20200602160102 24 323 16.1 25.7 0.00 0.00 0.00 38 1016.0
20200602153101 25 324 12.9 24.1 0.00 0.00 0.00 36 1111.2
20200602151603 25 330 16.1 29.0 0.00 0.00 0.00 35 1113.7
20200602140102 25 355 11.3 19.3 0.00 0.00 0.00 35 1017.0
20200602134602 25 338 8.0 19.3 0.00 0.00 0.00 36 1017.3
20200602133101 25 319 14.5 27.4 0.00 0.00 0.00 37 1017.6
20200602131603 25 326 11.3 19.3 0.00 0.00 0.00 36 1017.8
20200602120102 23 325 6.4 22.5 0.00 0.00 0.00 40 1018.6
20200602113101 22 3 9.7 25.7 0.00 0.00 0.00 40 1019.2
20200602111603 22 343 4.8 19.3 0.00 0.00 0.00 42 1019.2
20200602110102 22 342 8.0 16.1 0.00 0.00 0.00 43 1019.5
20200602104601 21 321 9.7 19.3 0.00 0.00 0.00 45 1019.6
20200602103101 21 329 4.8 12.9 0.00 0.00 0.00 45 1019.7
20200602101602 21 341 4.8 14.5 0.00 0.00 0.00 45 1020.0
20200602100102 20 326 4.8 11.3 0.00 0.00 0.00 46 1031.3
20200602094601 20 349 4.8 12.9 0.00 0.00 0.00 48 1054.5
20200602073102 16 58 1.6 4.8 0.00 0.00 0.00 55 1021.2
20200602071601 16 158 1.6 6.4 0.00 0.00 0.00 59 1021.3
20200602064602 14 194 1.6 4.8 0.00 0.00 0.00 64 1021.6
20200602063102 13 170 1.6 3.2 0.00 0.00 0.00 66 1021.6
20200602061601 12 168 1.6 3.2 0.00 0.00 0.00 68 1021.6
20200602060101 12 168 1.6 3.2 0.00 0.00 0.00 70 1021.7
20200602054602 11 168 0.0 3.2 0.00 0.00 0.00 72 1021.8
20200602053102 10 168 0.0 1.6 0.00 0.00 0.00 74 1021.7
20200602051601 10 164 0.0 1.6 0.00 0.00 0.00 76 1021.8
20200602050101 9 0 0.0 0.0 0.00 0.00 0.00 76 1021.7
20200602044602 9 164 0.0 1.6 0.00 0.00 0.00 76 1021.7
20200602043102 9 94 0.0 1.6 0.00 0.00 0.00 76 1021.7
20200602041601 9 94 0.0 3.2 0.00 0.00 0.00 75 1021.7
20200602040101 9 0 0.0 0.0 0.00 0.00 0.00 75 1021.8
20200602033102 10 0 0.0 0.0 0.00 0.00 0.00 74 1021.8
20200602031601 10 0 0.0 0.0 0.00 0.00 0.00 73 1021.9
20200602030103 10 0 0.0 0.0 0.00 0.00 0.00 73 1022.0
20200602024602 10 0 0.0 0.0 0.00 0.00 0.00 74 1022.1
20200602023102 11 0 0.0 0.0 0.00 0.00 0.00 73 1022.1
20200602020103 11 0 0.0 0.0 0.00 0.00 0.00 71 1022.4
20200602014603 11 0 0.0 0.0 0.00 0.00 0.00 71 1022.6
20200602013103 12 0 0.0 0.0 0.00 0.00 0.00 70 1022.6
20200602011602 12 119 0.0 1.6 0.00 0.00 0.00 69 1022.6
20200602010103 12 119 0.0 3.2 0.00 0.00 0.00 67 1022.6
20200602004602 13 119 0.0 1.6 0.00 0.00 0.00 66 1022.7
20200602000103 15 0 0.0 0.0 0.00 0.00 0.00 59 1022.7
20200601234602 15 119 1.6 4.8 0.00 0.00 0.00 58 1022.8
20200601233102 16 121 3.2 6.4 0.00 0.00 0.00 55 1026.6
20200601230103 16 102 1.6 11.3 0.00 0.00 0.00 59 1022.9
20200601223102 17 70 1.6 4.8 0.00 0.00 0.00 56 1022.8
20200601221603 17 59 0.0 3.2 0.00 0.00 0.00 57 1022.9
20200601220102 17 59 3.2 4.8 0.00 0.00 0.00 56 1022.8

Are you using loop2 ?
Can you capture a log with debug and data options enabled please. Preferably start MX with -debug so I can see the start of the log with debugging enabled.

The code around Davis pressures has not been touched that I know of since I took over the code, and I cannot see anything obvious in it that would increment the pressure at the moment - the obvious candidate would be the pressure multiplier/offset values being applied repeatedly.

I've sent a debug file by PM.

wxnow.txt appears to have settled down since resolving the WOW authentication problem last night, but i note what it is currently reporting, is slightly less than what CMX does.
I am happy to break the WOW login and see if it comes back and send you another log?

jon_iz wrote: ↑Thu 04 Jun 2020 10:43 am I've sent a debug file by PM.

Might be an idea to post the log files on here so we can see the symptoms to look out for. There's nothing "secret" logged in the file.

I put the incorrect station ID back in WOW - as that was the only thing I had changed.
I've left it running for over an hour and the wxnow.txt pressure has tracked at 0.3mb below station pressure (as expected)..
WOW hasn't spat an error out either in MXDiags (debug is not enabled, but it wasn't last night either, when I was seeing the errors)
So the only thing i can think of it may have been due to a back log of files backed up to go up to WOW in the first instance, with incorrect details.
Either way, I don't seem to be able to recreate either the wxnow or WOW errors again, so I'll just keep an eye on wxnow to see if the error pops up again.

I checked the outputs again this morning, and discovered a spike in pressure reported in wxnow.txt, after CMX had been running around 8 hours, so I have restarted in debug mode again this morning and left it running for around 6 hours.
Looking at data that is resolved from wxnow.txt, since I can see two further instances of spikes again this morning. This data, is transmitted into the APRS network every 10 minutes today, so it is reasonable to assume that the inaccuracies may be found in the data up to 10 minutes either side of the spike times, so approx 10:20~10:50 .

20200605105938 51 312 13.0 25.0 0.01 0.24 0.21 76 995.9
20200605104938 52 306 13.0 22.0 0.01 0.24 0.21 73 995.8
20200605103937 53 310 11.0 18.0 0.02 0.23 0.20 74 1018.3
20200605102938 52 311 13.0 22.0 0.02 0.23 0.20 75 1014.6
20200605101937 51 322 13.0 22.0 0.05 0.23 0.20 76 995.8
20200605100938 50 296 8.0 15.0 0.06 0.23 0.20 79 995.7

MXdiags Log attached.

Thanks for the log file.

The station appears to be sending the data correctly.

MX generates the altimeter pressure from the absolute pressure LOOP2 packets and multiplies it by the station elevation. Looking at the log, the absolute values came in correctly so I cannot see why you would be getting rouge readings.

There are only two variables in the calculation, if the elevation remained the same the calculated value should be OK.

The only other things that can affect the calculation are the "use loop2" setting in the ini file, and the Station Type. Neither of which appear to have changed.

So it's a mystery to me at the moment!

Thanks Mark,
Do you want me to restart daily with -debug for a few days to see if we can establish any kind of pattern?
Are there any other logs / switches to apply?