DA Client - UaGateway - UA Client

[PLP-Lackner]

I have DA Clients, they should connect to the UaGateway, and UA Clients should connect to the UaGateway.

So i want to build an exchange between da DA Clients and an UA Client and the UaGateway should be the connection.
Is this possible and how do i need to configure the UaGateway to get it work?

[Support Team]

Hi,

typically OPC is based on Client-and-Server communication, where Client is (active) data-consumer and Server is (passive) data-provider. Furthermore the OPC client/server interface and the services thereto are based on "variables", which is a list of data points that represent process values.

If you have 2 clients, where is the data comming from?
Which data are they going to consume?

With UaGateway you can create "cache" variables. That are data points that only exsist in memory. They are not related to any process value in the factory. There are persisted and non-persisted cache variables. Not intended for your usecase, but you might get your problem solved, one client can "write" to cache-variable and other client can "read" or better subscribe to same cache-variable.

You can create such "cache"-Variables using the Tagfile&Cache-Addon feature in the Uagateway.

See here for configuration:
https://documentation.unified-automation.com/uagateway/1.5.14/html/tagfile_import_format.html#tagfile_import_format_csv

Example configuration can be found here:
https://documentation.unified-automation.com/uagateway/1.5.14/html/tagfile_import_format.html#tagfile_import_format_csv_example

[PLP-Lackner]

There are many DA Clients which are the PLCs and one UA Client which is the Visu System.
Its also possible to make a UA Server instead of an UA Client on the Visu System if it is easier.

My Problem is, that the Visu System kann only use UA noch DA.

[Support Team]

Hi,

there is no way that two clients "directly" communicate. Only way is: Client to Server to Client.
Whereas client is active data consumer and server is passive data provider.

To get data exchange between two clients: one can write data into a server's tag variable, and second client can read this data point from the server. In addition you may need to consider some simple "watchdog" to get data consistency.