Forcing UA Gateway to Open Separate DA Connections per Client

[bodo.david]

Hello,

I am currently using FreeOpcUa clients connecting through UA Gateway to a Yokogawa HIS OPC DA server. I noticed that the Gateway seems to open only one DA connection per process, regardless of the number of Client() instances or threads created within that process.

Each thread/client instance uses a unique session.

ApplicationUri is also set uniquely for each client.

Despite this, the Gateway still appears to reuse the same DA connection, and we hit the 1000 monitored items limit on DA side.

It seems that only when a separate process is started, the Gateway opens a new DA connection, allowing another 1000 items.

My question:
Is there a way to force the UA Gateway to open multiple DA connections for the same client process?
We would like to exceed the per-connection limit without having to start multiple separate processes.

Thank you in advance!

[Support Team]

Hi,

no, there is no way to influence the behavior of UaGateway in terms of underlying connections. In fact the reduction to one connection only, is the key feature (load reduction) in UaGateway when connecting to underlying server. We never heard that underlying DA server is limited in number of "items per connection", in classic DA this is "unlimited". You should check with the Yokogava why they have limitation, maybe by configuration or maybe by license (but not technological limitation).

When using UaExpert client, can you see/use "more" items in the underlying server?

Unclear why you use multiple "instances/threads" with your FreeOpcUa client, typically one client may have multiple sessions, whereas each session has one (sometimes 2) subscription, which has multiple monitored items. Make sure you are not running is some "limitation" of your FreeOpcUa client implementation.