Hello,
I’m interested to store different variables groups by data change, independently. I mean, for example, the first variable group store all their values when any of its data change, but not the second variable group. This one only will store their values when any of its data change. Is it possible by defining correctly datalog config file? Thanks, Manel
Hello Manel, since we don’t support variable groups, you have to create 2 sessions, each of which logs one of the groups. Please create 2 configuration files for 2 sessions. Thanks & Best Regards Eduard
Hi Eduard, Now I have 3 sessions running, one for each “variable group”, and it is ok for me, but I have one more question about Datalogger RT: When PLC starts (any kind of start) Datalogger always stores variable values (my sessions are configured as data change) exactly at this moment, but my variable values (retain values) don’t change. I’m trying to store values at an exact moment by copying a value to my stored variable when it interests me. Is it possible to bypass this first storage when PLC starts? Thanks, Manel
Hello Manel,
The first saving of the variable values after the start is one of the basic functions of the RT-DataLogger and cannot be deactivated. As first, it is a reference point for future variable changes. The second reason is to ensure data consistency during recording. The DataLogger has a functionality to detect a data inconsistency, If this event occurs (e.g. during a restart / cold start / warm start), all variable values are saved because it can be assumed that the signal value was changed during the start up time. If you would like to store variable values via trigger signal in your application, you can use the DataLogger FB in PLCnext Store: https://www.plcnextstore.com/#/169 If you have any further questions, please do not hesitate to ask! Best Regards Eduard
Hi Eduard,
I knew this library but I decided not to use it on my program because I want to consume all stored data over OPC UA. I also wanted to take advantage of the file size management provided by the datalogger RT.
It could be interesting to add storage based on a trigger, not only on data change or sample time on DataLogger RT, although I understand that you are developing as generic tool as you consider. Thanks for your response,
Manel
Hello Manel The trigger for the variable data storage is the task cyclic interval. If you define an event task (with variable groups) and start it in your program (in a cyclic task), you can also trigger the time of the variable data storage. Maybe it’s a possible solution. Best Regards Eduard
