How to use node-opcua to read from OPC DA Server?

Question

The repository page for node-opcua says it supports DataAccess. But I was not able to find any example in which it connects to an OPC DA server and reads data.

So far I've tried the server_with_da_variables example. I have been able to read its data using sample_client.

Is the method same as connecting to OPC UA Server? Do we use endpoint URL and create session and read using NodeId, or is the procedure different?

It supports OPC UA Data Access, not OPC DA. The OPC classic specifications (OPC DA + OPC AE + OPC HDA) are almost 20years old. The latests specification: OPC UA specify Data Access, Alarms & Conditions and Historical Data Access — Camille G., Oct 21 '16 at 06:31

score 2 · Answer 1 · answered Oct 21 '16 at 06:31

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The "DataAccess" probably refers to Data Access features in OPC Unified Architecture (Part 8 of the OPC UA spec), and not to the COM-based OPC DA.

answered Oct 21 '16 at 06:31

ZbynekZ

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score 0 · Answer 2 · answered Oct 21 '16 at 14:02

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I agree with ZbynekZ.

While confusing, when someone refers to an "OPC-DA" server they are referring to a COM-based server 99% of the time.

If you want to access a COM-based server through OPC-UA you'll need to put a UA wrapper application in front of it.

answered Oct 21 '16 at 14:02

Kevin Herron

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do you know of any node based OPC DA Client? – Dushyant Bangal Oct 24 '16 at 07:41

How to use node-opcua to read from OPC DA Server?

2 Answers2