Using Labview with Mitsubishi OPC Server

[Ian_Billingsley]

We are really stuck with talking to the Mitsubishi Driver through Labview 6.0.2.

Here is a screen dump taken from the Browse to OPC item.vi Example.

This is taken just before Labview Crashes!. If we click on the object it will crash.

You can see the Melsoft device, and the group Mxdev0 and the object X:20 - X:2f....


You can also see that the NI OPC Explorer is running with successful linkage to the object....

Can anyone tell me what the exact URL should be for addressing this object?

I can get a basic Datasocket Read vi to run without error using the following URL:

opc://Localhost/Melsoft.MCSOPC/MXDev0/X:20 - X:2f

But the data that is returned from this URL is not the Right Data!.....It simply returns
a Zero!

So my question probably; what is should the final part of the URL look like? I.e (/X:20 - X:2f)?

The Mitsubishi OPC Server that we are using is "MX MCS OPC SERVER" Version 7 10.200

Regards
Ian Billingsley

[Roli]

Ian,

We had the same issue several months ago with another customer using Mitsubishi's OPC Server.
And we confirmed that the bug is in the OPC server. The server is deliting an object that provides the interface "IEnumOPCItemAttributes" when we still have a reference to it. This violates the IUnknown interface contract.

We can avoid their bug by releasing our interface prior to informing the server that we're done with the group.

A patch that avoids this bug in the Server is attached for LV DSC 6.0.2. Move the attached file LVOPCClient.dll to /vi.lib/system folder.

Once we figured out this wrong behavior in the OPC Server we could point the Mitsubishi's OPC developer to other problems and they fixed them in newer versions of their OPC
server. We tested the OPC Server Version 7.10.207 together with DSC 6.0.2. NI recommends to contact Mitsubishi for the latest Server.

Hope this helps

Roland
National Instruments