DataLogger - Config-File for slow logging

PLCnext Technology & PLCnext Controls
1

I’ve the following problem: I want to log GSD-Data just every 1s to the sqlite database an read the values every 60s from the database. I’ve configured the data-logger.config this way: The problem is that the data is written to the db-file all 1000 values instead of all 60s (for testing i just have one value). Could it be that the system ignores my config => the 1000 values seems to be the default. would by nice if you could send the correct config-file for my task! Thanks

2

sorry the input mask ignores my config-file => the important line: General name=“test-session” samplingInterval=“1s” publishInterval=“60s” bufferCapacity=“60” Thanks

3

Hi synron, the trick is to understand the relation between “publishInterval” and “writeInterval”, and yeah we’ve to improve here the documentation ?. I guess the following helps:

                                               1. **Source Task**

The producing task of the configured GDS port copies in the configured the values into an internal buffer
After the max. is reached, are the old values overwritten → ringbuffer.

The buffer is copied according the the into the data sink in the RAM.!

                                               2. Data sink - RAM

To protect the SD card (internal/external) is the data sink updated in the first instance always in a RAM copy.
After a max amount of entries are reached () is the data sink updated on the external SD card.

In your case is also the setting of the important to get the updates on the external SD card and the default setting is 1000. So, a possible configuration could be: General name=“test-session” samplingInterval=“1s” publishInterval=“30s” bufferCapacity=“60” `
``writeInterval=“60”** maxFileSize=“4000000”

` Reg Frank

4

Hello Frank, thanks for your answer! Work’s perferkt! I got my info from the GitHub-Repository https://github.com/PLCnext/PLCnext_RT_Datalogger! Would be nice, if you could describe the working of the “writeInterval” - Variable in the articles! => could find it nowhere! Thanks!

5

Hi syncron, yeah I know, we’re working on that :slight_smile: cu Frank

6

Hello Frank, just to be shure: writeInterval is not a timeinterval but an ammount of records in the temporary RAM data sink. The db file on the sd Card ist updated with the records from the temporary RAM data sink every time when this ammount is reached. For example: samplingInterval =“60s” publishInterval=“60s” bufferCapacity=“200” : sampling and publishing up to 200 items every 60 seconds writeinterval=“10” : updateing the db file every 10 records, in this case every 10 minutes Is that right? Thanks