Hi!
I’m using influx to gather the rotational speed of some motors via OPC UA. this works great and now I have the task to process the data further.
In the screenshot you see the raw values of the sensor as blue graph:
In a first step I used the map() function to define a threshold to distinguish a work cycle. In the code below every time the speed exceeds 200 rpm the value is capped at 200. In the end the mapped values would be 1 and 0 but for development I like to see the graph.
from(bucket: "system_data")
|> range(start: v.timeRangeStart, stop: v.timeRangeStop)
|> filter(fn: (r) => r["_field"] == "FEU-BS01")
|> map(fn: (r) => ({_measurement: r._measurement,
_time : r._time,
_field : r._field,
_value : if r._value > 200 then 200 else 0})
)
This gives me the purple graph which only has two values, 200 or 0, like a digital signal only has “high” or “low”.
The next step would be to reduce the data further, and this is where I fail. In the end I need a table/bucket where just the begin and the end when the graph is “high” or “low”. This should look like this:
value start stop
200 2022-08-01T06:00:00 2022-08-01T06:12:20
0 2022-08-01T06:12:20 2022-08-01T06:23:40
200 2022-08-01T06:23:40 2022-08-01T06:31:00
0 2022-08-01T06:31:00 2022-08-01T06:35:10
200 2022-08-01T06:35:10 2022-08-01T06:35:10
...
How can I do this?
Kind regards Christoph
