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data collection inverval

Topics: 1. General, 5. Support
Feb 24, 2015 at 6:20 AM
Hi.

I was wondering if the data collection interval could be reduced to 1 minute.
The reason for this is that I find when the cloud shadows the panels the reduction on the output can skew the numbers.
I prefer that the database store the data rather than using the CSV option.
I plan to average out the 4min collection.
Feb 24, 2015 at 8:34 PM
You can change it like you want, but if your inverter is BT connected, don't make it too short.
Spotdata you send to PVOutput will be rounded anyway
Feb 27, 2015 at 8:52 PM
Edited Mar 2, 2015 at 9:01 PM
dear madether, i do fully understand your demand

-A- the production from your panels is directly dependent from solar radiation,
hence cloud-evolution will have a major influence on the production

if you speed-up the collection rate (in OPTIMAL condtions you might reach a collect rate at each four seconds)
then, you will find that with cloud evolution the production will effectively vary, and
in short intervals (<5seconds) you'll find variations with a factor 8 (eg from 3200<->420Watts)

so - if this type of changing values is a problem
then in my opinion you must reconsider the analysis while the cause of these changes is very natural


-B- be aware about some limits when using the basic tool sets
-B.1- the "Operating system" includes a standard limit such that "tasks" (cronjobs eo) can only be repeated each minute
for most applications this fits for the needs
-B.2- you will experience that at regular instances (due to the internal functions of the inverter)
sbfspot will report that more then one connect trial is needed (up to 4trials is normal behavior)
(4 retries to connect means that your inverter needed up to 40seconds to reply)
if you want to setup a system with sbfspot executed each 30seconds (or less then30)
you will need to create scripts for this,
in these scripts you must include a control-method to avoid to run sbfspot more then once at a time

-B.3- anyway standard cronjobs will start at the minute
so if you intent to run sfbspot more then once in a minute then you have to use a script

kind regards wim
Mar 7, 2015 at 8:07 AM
I have set cron to 1 min intervals. As my inverter is connected via ethernet I am happy with the resolution now.
Seems to work well this way. I offset my uploading to PVoutput at 6 min intervals which is working well too.