OPC-DA

The OPCDA protocol is a service-oriented architecture that does not work polling information, instead uses a subscription and notification system, letting the server monitor the queried items. OPCDA is a protocol based on Microsoft’s COM/DCOM2 interface do write and read data in automation and uses the Node Ids to find the queried items, grouping them in a Subscription. These Node Ids are also called Tags.

In this example, we can see that an OPCDA Source should have a single Request and the following information must be provided:

Name	Description	Required	Default Value
object	Protocol name	opcda
query_period	Execution interval, in seconds, of each request	yes
uid_log	Request identifier	no	1
enabled	Request collection enabled	no	false

The OPCDA Source also needs a ProgID and a CLSID. These values could be configured on the screen or concatenated directly on the field. In the example below OPC.Simulation.1 is the ProgId and f8582cf2-88fb-11d0-b850-00c0f0104305 is the CLSID, always following the pattern opcda://{computerAddress}/{ProgID}/{CLSID}. The username and password must reflect the server’s computer user settings.

<source>
    <name>OPC-DA-DEMO</name>
    <enabled>true</enabled>
    <mode>client</mode>
    <rig_name>NS04</rig_name>
    <service_company>intelie</service_company>
    <protocol_name>opcda</protocol_name>
    <protocol_version>0.0.0</protocol_version>
    <endpoint>
        opcda://127.0.0.1/OPC.Simulation.1/f8582cf2-88fb-11d0-b850-00c0f0104305
    </endpoint>
    <username>Administrator</username>
    <password>admin</password>
    <requests>
    <request>
    <object>opcda</object>
    <query_period>20</query_period>
    <uid_log>1</uid_log>
    <enabled>true</enabled>
    </request>
    </requests>
</source>

The same example could be configured through the source page, at the collector's tab:

OPC-DA Source Configuration

OPC-DA Source Configuration

The Liverig collector also requires the Node Ids (Tags) values, among other information, to query properly. These values should be configured at the store.json file.