How can I define type of data when I'm reading string via OPC server?

[IVAN_TRIFONOV]

Hello!

I have system that you can see on attached picture.

The problem zone is marked red.

In best case I got "0x0000 0x0000" string.

I think I must correctly select type of data.

I tried STRING, ARRAYS of U8,I8,U16,I16 but without result.

How can I define type of data and get data?

Thanks.

[RavensFan]

Where is your LabVIEW code?  There is nothing attached for people to see how you programmed this.

[IVAN_TRIFONOV]

Code is in the attachment.

[Ben]

If you replace the numeric with a string and use the URL of this web-site, it would return the HTML for these discussion forums.

My point is you need to know what is on the other end associated with that URL to answer your question.

Ben

[IVAN_TRIFONOV]

When I read 10 holding registers directly via Modbus/RTU (without the OPC server), I get 10 U16 words.

They include the following information:

reg1/reg2         reg3/reg4            reg5/reg6          reg7/reg8        reg9/reg10

selected           measurement     measurement    min allowed    max allowed

physical unit     value of PMC1   status                 value              value

Pair reg3/reg4 has float value.

Quote from programmers guide (EPHUM011):

'You cannot read selectively the registers 3 and 4 for the measurement value only. You have to read the
entire length of the command (10 registers) and extract the desired information."

When I read the same data via OPC, I get "0000 0000 0000 0000".

When I open the window of the OPC server, I see the picture I attached.

I.e. OPC server successfully read data, and they have type "string" (string of what?)

Question is: may be should I request type of data from OPC server, and then read that data in right format?

And how can I do that?

[tolltroll]

What output do you get if you don't specify the datatype at DataSocket Read? Or if you read it as a string? The data may be being parsed in a way that we're not expecting.

Nick

Applications Engineer

National Instruments

[IVAN_TRIFONOV]

I collected a lot of variants. Silly variants is here too.

I uploaded 2 pics for every variant: VI and output of VI.

I attache ZIP file because count of the attachment in this forum are limited.

First two variants show that I can read something from my OPC server.

Other variants show that I can read not all from my OPC server yet 😞