• check the server status
• test the behavior of an XML-DA service
• change item values to test the reaction of clients
• detect item value changes to test client actions

Usage:

The TestClient reflects the OPC XML-DA concept and does not use permanent connections. This means that the server methods can be called without first making a connection. To access another server only the URL needs to be changed.

Subscriptions are an exception in a way that the SubscriptionPolledRefresh and SubscriptionCancel functions depend on the previous Subscribe function. A Subscribe starts a subscription in the server that is active until it is cancelled or has timed-out. When tehe client starts subscriptions in multiple XML-DA servers then the proper URL has to be selected before a SubscriptionPolledRefresh  is executed. Otherwise the poll request is sent to the wrong server, which doesn't know the subscription handle and returns an error.
Subscriptions to multiple OPC-DA servers all go through the same one Wrapper and can be polled in one call. If currently an OPC-DA server URL is defined then the poll request goes to the OPC-DA wrapper and it knows the subscriptions of all it's OPC-DA servers.

Server URL
The URL of XML-DA servers must start with http: and has the form   http://localhost/webservicedirectory/servername.asmx
OPC-DA servers are specified as:
a) the ProgId only for local OPC DA-Servers.  E.g.   Advosol.SimDAServer.1
b) with computer name for remote servers.  E.g.   //I-3000/ Advosol.SimDAServer.1
c) with access definitions.E.g. //I-3000/Advosol.SimDAServer.1?User=xx&Password=xx&Domain=xx
d) optionally the definition can be preceded with opda:   E.g.  opcda://I-3000/ Advosol.SimDAServer.1

XML-DA server access Credentials can be defined in the Credentials menu item.

Operation Mode

The test clietn application is provided in two versions: