The OPC UA Client Plug-in includes several triggers.
The datachange trigger is configured for an OPC data point and triggers the transfer when the data point changes.
The limit value Trigger monitors a data point for compliance with limits. It can be checked for exceeding or falling short. A hysteresis can also be set.
Handshakes are often implemented for data transfers. The bit trigger is the simplest variant here. The OPC router checks whether a bit requests a transfer. Once transferred, the bit is optionally reset or another bit is set as response. The success of the transfer can be transferred to another data point.
The message trigger is the further development of the bit trigger in the form of telegram data exchange. Here not a bit is checked, but a counter is checked for a value change. In response, the number that triggered the transfer is written back after the transfer.
The reliability and traceability of this exchange is significantly higher.