Increase Grafana graph resolution

[Vic]

Hi,

Last night, i've been playing around with SignalK, influxDB and Grafana. The main goal is to use this openplotter setup for seatrails. What we want to log and show on graphs is the position, heading, heel and pithch of the yacht over a specif time. Now the challenge is, that the resolution of the plotted data in Grafana is about 1 second. Is there a way to get this resolution up to say at least 0.2 seconds?

For now, i don't know where to search. Is it that the signalK pass through influxDB isn't high enough (what is the pass through resolution of signalk?)? Or is it that Grafana doesn't show higher than 1 second?

regards,
Wouter

[tkurki]

The only limits in sensor to Influx are the native update rate of your sensor and db write resolution in InfluxDb plugin settings, defaullt 200 milliseconds. I don’t think Grafana has a limit here, try selecting last 15seconds for example.

So no limits if you configure things correctly.

Use the Logging plugin to log your input data independent of InfluxDb to see what your input actually looks like.



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[Vic]

ah, thanks for the reply. 

I've tried the logging plugin which was in the list of available apps. But i couldn't locate the log-files. Do you know were I can find them?

If you mean the logging incoorperated in the "Server-tab" of the signalk web page (i.e. Data log files), i've found these files. And also i've attached one here. The times stamp doesn't make any sense to me. But when I count the amount of lines in this file, it seems that the logging is every 0.5 seconds. But somehow I cannot see this in the Grafana page?

Also, as you indicated, the logging should be about 0.2s? 

regards,
Wouter

[tkurki]

If you mean the logging incoorperated in the "Server-tab" of the signalk web page (i.e. Data log files), i've found these files. And also i've attached one here. The times stamp doesn't make any sense to me. But when I count the amount of lines in this file, it seems that the logging is every 0.5 seconds. But somehow I cannot see this in the Grafana page?

Also, as you indicated, the logging should be about 0.2s? 

The timestamps are milliseconds since Jan 1st 1970. See for example https://currentmillis.com/ Yes, they show data every 0.5 seconds.

200 ms is the minimum interval of data per path written to InfluxDb. If your sensor produces data every 500 milliseconds all of it is written - the limit only concerns data that is produced more often than at 200 ms intervals.

Did you check that the setting is at default in the plugin configuration?

If you zoom in in Grafana so that time span is just some seconds what does your data look like? Have you tried turning on "Points" in visualization properties?

Running out of ideas, works ok for me with sub second sample intervals.