Professional OPC
Development Tools


Online Forums

Technical support is provided through Support Forums below. Anybody can view them; you need to Register/Login to our site (see links in upper right corner) in order to Post questions. You do not have to be a licensed user of our product.

Please read Rules for forum posts before reporting your issue or asking a question. OPC Labs team is actively monitoring the forums, and replies as soon as possible. Various technical information can also be found in our Knowledge Base. For your convenience, we have also assembled a Frequently Asked Questions page.

Do not use the Contact page for technical issues.

Can't read or write with TOP Server

29 Aug 2017 17:30 #5462 by support
Below is the original post:

I've inherited tests from someone who is no longer with my company. We're using v 5.35.442.1 to connect to a variety of PLCs.

Everything works fine except for a Siemens S7-200. We're using TOP Server v 5.20.396.0.

When the code tries to write, an exception is thrown:
Caught Exception=OpcLabs.EasyOpc.OperationModel.OpcException: An OPC operation failure with error code -2147467259 (0x80004005) occurred, originating from 'OpcLabs.EasyOpcRaw.DataAccess.RawEasyDAClient'.
The inner exception contains details about the problem.
---> System.Runtime.InteropServices.COMException: Unspecified error
--- End of inner exception stack trace --- at OpcLabs.EasyOpc.DataAccess.IEasyDAClientExtension.WriteItemValue(IEasyDAClient easyDAClient, ServerDescriptor serverDescriptor, DAItemDescriptor itemDescriptor, Object value) at TopSrvrTest.Program.SendReset(String opcServer, String resetAddress) in C:\Users\dlaw\Documents\Visual Studio 2015 \Projects\TopSrvrTest\Program.cs:line 20

When attempting to read, no exception is thrown, but the DAVtq variable's HasValue property is always null.

I have a small program that reproduces the issue (and also shows successful reads and writes for a MicroLogix 1400B), but if I attach it, I can't post to the forum.

The code is very simple, however. For writes:
EasyDAClient dac = new EasyDAClient();
dac.WriteItemValue("SWToolbox.TOPServer.V5", ISOTCP.S7_200_58.RESET", true);

For reads:
dac.ReadItem("SWToolbox.TOPServer.V5", "ISOTCP.S7_200_58.VW1920, DAReadParameter.DeviceSource);

Please Log in or Create an account to join the conversation.

29 Aug 2017 17:28 #5461 by ifdefelseif
Absolutely! The problem was that the IP address had changed after a power failure and I had to update the network interface for the TOP Server

Please Log in or Create an account to join the conversation.

29 Aug 2017 17:23 #5460 by support
Ok Thanks - I was just about to reply.

Next time, can you please keep the original post intact, as that is the purpose of these forums - to facilitate lookup of similar issues and help other users.

Would it be OK if I re-post it here, just for record?


Please Log in or Create an account to join the conversation.

29 Aug 2017 15:11 - 29 Aug 2017 16:54 #5458 by ifdefelseif
Issue resolved. The problem was with the network adapter.
Last edit: 29 Aug 2017 16:54 by ifdefelseif. Reason: Resolved

Please Log in or Create an account to join the conversation.

Moderators: support
Time to create page: 0.066 seconds