Job-Trigger via OPC UA

OPC Unified Architecture (OPC UA) is a standard for data exchange and makes it possible not only to transport machine data (control variables, measured values, parameters, etc.) but also to describe them in a machine-readable (semantic) form.

Image: Logo Job Trigger via OPC UA

versiondog supports OPC UA as a client-server-architecture. This tutorial will outline the scenario where the OPC UA server runs on the PLC and versiondog acts as 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 a versiondog job can be executed directly from the PLC via a variable rather than scheduled or manually. A few examples are:

• Via a push button at the location: When the programmer is finished with his changes, he can press a button or knob to trigger the backup via versiondog.
• After finishing a longer processing of a workpiece: to ensure that the backup is not performed during processing, the job can be executed before and after processing via a variable.
• When changing from manual to automatic mode, a job will be initiated and the data blocks will be saved.
• After parameter transfer on a panel, for example, if someone changes a formula, a job will be automatically initiated.
• It can also be useful to perform a backup after a tool change, the end of a cycle, before a new batch size begins, or after a status change.

For this purpose, an OPC UA Client was integrated into the versiondog server. This client communicates with an OPC server that cyclically reads the controllers that are intended to be backed up and provides the values of the trigger variables to the versiondog server.

The following diagram shows in which environments the job trigger can be used via OPC UAImage: Integration job trigger via OPC UA