Author Topic: La Crosse V40-Pro Pressure Values Consistently Low  (Read 85 times)

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Offline Cloudscout

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La Crosse V40-Pro Pressure Values Consistently Low
« on: July 09, 2018, 02:18:17 PM »
I picked up a La Crosse V40-Pro "Professional Remote Monitoring Weather Station" last week.  I got it connected to WU but the pressure readings that it's reporting to WU are consistently 0.2 in/hg lower than the results reported by the nearest airport (about 6 miles away) and another PWS operated by a local TV station about 2 miles away.  I have a BME280-based device that I built and when I correct its readings to sea level pressure, it is always within about 0.01 in/hg of the airport and the TV station's numbers as well.  The relative changes in pressure seem to be okay but the actual numbers are consistently low and it's driving me crazy.  Any thoughts?

Offline Jstx

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Re: La Crosse V40-Pro Pressure Values Consistently Low
« Reply #1 on: July 10, 2018, 09:45:23 AM »
Does this unit, or it's software handling interface, have an accessible options menu?
Most PWS's do, which should allow you to input an "offset" factor value to make corrections to a slightly 'off' sensor.
My La Crosse Tech WS-2813 can apply 'corrections' at the console itself, or in the WUHU logger software app, which has extensive options.

Offline Cloudscout

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Re: La Crosse V40-Pro Pressure Values Consistently Low
« Reply #2 on: July 12, 2018, 04:25:58 PM »
No, there's no option for an offset or anything.

The deviation was much worse but it improved when I restarted the station.  I restarted it again but it didn't make a difference.  The next day, I tried restarting it again.  This time, the accuracy improved a little more.  I waited another day and restarted the unit one more time.  Now its accuracy seems good.  It's generally within 0.02 in/hg of what my other sensor, the local news station's PWS and the nearest airport's METAR numbers are showing.