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Real-time DataLogger

Available from label 2019.6

Use Case

As soon as you record consumption values, need to prove energy feeds, or possibly have to log plant states, you need a reliable data acquisition. With the PLCnext Real-Time Datalogger, you now have a convenient way to do all these use cases without any programming effort. Simply parameterize the required variables, and the DataLogger starts with a task-synchronous recording. The data is available directly on the SD card of the controller, or you can rely on OPC UA Historical Access.

In addition, you can decide whether each value or only changed values are being recorded. This is how a simple data logger becomes a powerful event recording system ("Sequence of Events").


The DataLogger is a service component of the PLCnext Technology runtime. This component transfers real-time data from the GDS to a database for recording and storage purposes. 

This simplified schematic drawing shows how the DataLogger works:

When starting and stopping the PLCnext Technology runtime, a configured DataLogger session is started and stopped automatically. The DataLogger then collects the task- synchronous values of the configured GDS ports with a given sampling rate and stores them with a time stamp (exact to 1 µs) into a RAM disk.

With the standard settings, the database is stored SQLite-compliant on an SD card in the PLCnext Control. Then you can copy the database at any time, read it out in place via OPC UA Historical Access, or read out entries via a C++ interface (Remote Service Calls). All essential settings are given by an XML configuration file, no further programming is necessary.

For more details, explore this drawing; it shows even the keys of the configuration file:


How to start

After this short introduction, here you find further information on how to use the DataLogger:

  1. DataLogger configuration – read how to set up a DataLogger session
  2. DataLogger video tutorials – watch how to set up a DataLogger session (all modes covered)
  3. DataLogger reference – find all about recording modes, timestamps, intervals and the data sink to use
  4. RSC IDataLoggerService2 – learn about the Remote Service Call (RSC) for the DataLogger




 • Published/reviewed: 2020-08-07 • Revision 35 •