Timeseries

The logger group of object IDs (with the exception of the event log) returns time series data (values with an associated timestamp taken at regular intervals) as a long response. Similar to th event log, the data is queried by writing a UNIX timestamp to the object ID, uppon which the device returns data that was logged before that timestamp. The amount of data varies similar to the event log, so in order to get a full days of data for a single time series, an average of 7 queries are required.

As with the event table, the first element is a unix timestamp, repeating the value written to the object ID. Then follows a list of pairs, first a UNIX timestamp and then the floating point value.

Thus, the request data type is INT32 for the timestamp, and the response data type is the special TIMESTAMP data type to cause the decode_value() function to correctly parse the data into a data structure.

Data resolution

The data resolution varies between object IDs. Object IDs with minutes in their name, such as logger.day_egrid_load_log_ts have a resolution of 5 minutes.

Time part	Resolution
minutes	5 minutes
day
month
year

Data storage

The devices use some sort of ring buffer to manage their data, meaning that old elements are overwritten as new data is stored. For minutes graphs, this leads to ~90 days of history.

Data format

All elements are always 4-bytes long and are either UINT32 for the timestamp or FLOAT for the value.

Number	Meaning
0	Query timestamp, repeated from the write request.
1	Timestamp 0, associated with the following element.
2	Value 0.
3	Timestamp 1.
4	Value 1.
5	Timestamp 2.
...	...

Unless an error occurs, the structure is always <number of entries> * 2 + 1 4-byte sequences, the extra sequence being the timestamp at the very beginning.