Some comments below.
Gary
On Wednesday, 16 April 2025 at 18:13:29 UTC+10 mihec wrote:
Gary,
I have edited the weewx.conf with proposed configuration. I am still not
getting the values correct. I do have: rainDay, rainWeek, rainMonth and
rainYear values in the weewx's database.
Just one point of clarification. The cumulative field used in a [[Delta]]
stanza need only appear in loop packets/archive records, there is no need
for it to be saved to the WeeWX database. It won't hurt if it is, but there
is no requirement.
Maybe I don't understand the logic behind the [[Delta]].
I have few questions:
1. Does the logging interval matter? I am polling the data every minute and
store it to the fileparser's compatible format. However, looking at the log
file, I see that the records in the weewx.sdb do not update every minute.
There are occasions where a minute is skipped (say 1 time per 10 minutes).
I don't know the reason.
Not sure what you mean by 'the logging interval'. When using the fileparse
driver there are a few intervals/periods of interest. First you have the
interval at which the fileparse source data file is updated. This is
typically completely external to WeeWX. Then you have the fileparse driver
polling interval, this is the interval used by the fileparse driver to read
the source data file and generate a loop packet. In effect the fileparse
driver will emit a loop packet every polling_interval seconds). Ideally the
driver polling interval is shorter than the source data file update
interval. How much shorter is somewhat subjective, if it was me I would
have my polling interval 1/3 (or less) of the source data file update
interval. If your source data file update interval and polling interval are
the same you risk missing data (ie the source data file is updated twice
before fileparse polls it). The final interval of concern in the WeeWX
archive interval, this is the interval at which (in the case of the
fileparse driver) WeeWX generates an archive record and saves the record to
database. The WeeWX archive interval should be greater than the driver
polling interval, if they are the same or the archive interval is less than
the polling interval you will have archive periods where WeeWX does not
receive any loop packets from the driver and consequently no archive record
is generated and no archive record would be saved to database.
As an example, if you were updating your source data file every minute you
might set the fileparse driver polling interval to 10 seconds and the WeeWX
archive interval to five minutes.
2. To avoid midnight time discrepancies, I am using the dateTime value
provided by the data source (Ecowitt cloud) and provide the "dateTime=<>"
string to the fileparser. Is this valid to do? I have also tried without
this. Explanation: when polling for the data few seconds over 00:00, I get
data from 23:59. If I let weewx use the actual OS time, the "rainDay" would
be wrongly logged to the next day.
I am not sure exactly what you mean. Are you obtaining data from
Ecowitt.net to produce your source data file? If so you need to be very
careful of latency. For example, when your station posts data to
Ecowitt.net there is a delay while the data is processed by Ecowitt.net and
then made available via the Ecowitt.net API. There will then likely be a
delay until you poll the Ecowitt.net API, obtain the data and generate the
source data file. You then may have a delay before the fileparse driver
polls the source data file and generates a loop packet. The fileparse
driver timestamps each loop packet with the time the loop packet is
generated, not the time the original data was uploaded to Ecowitt.net, so
there could well be cases where a loop packet may contain data from a
previous loop period rather than the current loop period. This could cause
discrepancies between data on Ecowitt.net and WeeWX. This would especially
be the case for obs such as rain.
Why is using e.g. rainMonth or rainYear better than rainDay?
The per-period or 'delta' values are obtained by taking the difference
between a current cumulative value and the last cumulative value.
Cumulative fields such as rain usually reset to zero after some time (eg
each hour, day, week, month, year) or when the counter rolls overs (perhaps
for an all-time or total rain value). When the cumulative value jumps to
zero the delta value for that period cannot be determined, so if any rain
fell in that period it would be lost. When using a hour based cumulative
value that reset to zero happens once per hour or 24 time per day, whereas
for a year based cumulative value the reset to zero happens once per year
and there is much less chance of any rainfall occurring in a reset period.
If no rain ever falls in the reset period there will be no
problem/discrepancy, but eventually it will. Best to minimise the risk by
maximising the reset period of the cumulative value used. Hence the
preference for year rain over day rain or hour rain.
Thank you.
nedelja, 6. april 2025 ob 13:53:47 UTC+2 je oseba gjr80 napisala:
Provided you are running WeeWX v4.2.0 or later you need to make the
following changes to the [StdWXCalculate] stanza in weewx.conf:
1. under [[Calculations]] add an entry as follows:
rain = prefer_hardware
2. add a new stanza [[Delta]] after the [StdWXCalculate] [[Calculations]]
stanza:
[[Delta]]
[[[rain]]]
input = dailyRain
where dailyRain is the name of your cumulative rain field to be used to
calculate WeeWX field rain. If you have more than one cumulative rain field
use the one that resets least frequently, eg use day rain in preference to
hour rain, year rain in preference to month rain etc.
your [StdWXCalculate] stanza should look something like:
[StdWXCalculate]
[[Calculations]]
....
rain = prefer_hardware
[[Delta]]
[[[rain]]]
input = dailyRain
After making the changes save weewx.conf and restart WeeWX. WeeWX should
now correctly populate the WeeWX field rain.
Gary
On Sunday, 6 April 2025 at 00:07:45 UTC+10 mihec wrote:
While looking for solution to my issue, I came around this post.
I am using fileparser to log data from my remote weather station (Ecowitt)
and everything works fine except the rain. I have implemented my own
pre-processing where I log the delta-rain but that doesn't work for some
reason (might my timing issue in the scripts). I am logging the dailyRain
and other values, too. Just in case. I don't know how to e.g. use the
dailyRain in the NOAA report.
As I read this: https://github.com/weewx/weewx/issues/491
I assume this could resolve it. Are there any more details on the use?
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