Transfer Objects

The following overview lists the available transfer objects for the OPC client and shows at a glance whether they are supported by OPC Classic and/or OPC UA.

transfer object	OPC Classic	OPC UA	Description
OPC Data Access	✅	✅	Reading or writing one or more current values on the OPC server.
OPC Dynamic Read	✅	✅	Reads dynamic items passed at runtime via the configured OPC connection and returns the read dynamic values as a list.
OPC Dynamic Write	✅	✅	Writes dynamic values passed at runtime to the OPC paths of the configured OPC connection, which are also passed at runtime.
OPC Structures	–	✅	Enables reading and writing complex data types (structures and structure arrays) from an OPC UA server. Example: Current job defined as a structure in the PLC.
OPC Message	✅	✅	Secure transmission of OPC telegrams via change counters with an optionally configurable response telegram.
OPC Methods	–	✅	Call OPC UA methods on the target OPC server. In OPC UA, methods provide both input and return parameters. Example: Euromap 77 includes a method for starting a job. This allows the machine to execute various logic operations within the call and return the result.
Multiple OPC Read-	–	✅	Dynamically read changes under a selected OPC node. You can set filters to include desired elements and exclude undesired ones.
OPC Batch Read	–	✅	The OPC Batch Read transfer object simplifies reading multiple OPC values with a uniform structure without having to specify each value individually. Example: Reading lists of jobs along with their properties. The job structure and list length need to be defined only once.
OPC HA Read	–	✅	“OPC HA Read” Reads data from an OPC UA historian or OPC UA HA server and provides historical value trends or aggregated values for further use in the OPC Router.

Notes

• ✅ = supported
• – = not supported
• Transfer objects such as methods, structures, batch read, historical access, and dynamic node read are only available with OPC UA.
• The "OPC Read Mode" setting for the connection determines which transfer objects follow this setting and which always read directly from the server; this is described in the section on reading and writing.