Job trigger via OPC UA¶

OPC Unified Architecture (OPC UA) is a standard for data exchange and enables machine data (control variables, measured values, parameters, etc.) not only to be transported, but also to be described in machine-readable (semantic) form.

versiondog supports OPC UA as a Client-Server architecture. This tutorial describes the scenario where the OPC UA Server runs on the PLC and versiondog acts as an OPC UA Client. In this case, it is possible to trigger a job in versiondog via a variable on the PLC using OPC UA.

There are a number of possible use cases where you can execute a job not by schedule or manually, but via a variable directly from the PLC. A few examples are:

• Via a push button on site: When the programmer has finished making changes, he can press a button or a button to trigger the backup via versiondog.
• After finishing a longer machining operation on a workpiece: To ensure that the backup is not executed during machining, the job can be executed before and after machining via a variable.
• When the operating mode is changed from manual to automatic, a job is triggered and the data blocks are saved.
• After parameters are transferred to a panel, for example if someone changes a recipe, a job is automatically triggered.
• After a tool change, after the end of a cycle, before a new batch size begins or after a status change, it can also be useful to perform a backup.

An OPC UA Client has been integrated into the versiondog server for this purpose. This client communicates with an OPC server, which cyclically reads the controllers to be backed up and provides the values of the trigger variables to the versiondog server.

The following diagram shows the environments in which the Job Trigger can be used via OPC UA.