CODEWITHSUNDEEP
c#comopcresponse-timeopc-da
Erik Linden
Erik Linden

Reputation: 131

OPCDA read time

I am polling an OPCDA server for data every second. I use the standard .NET DLL's from OPC Foundation to achieve this.

My service is located on the same server as the OPCDA server. However, my read times are often around 900-1000ms. Is this normal or something wrong in my code or server setup? I poll around 20 OPCDA tags. What is a "standard" response time of such an operation or is it impossible to say?

Upvotes: 2

Views: 1250

Answers (3)

PaulWaldman
PaulWaldman

Reputation: 285

What OPC server are you using? There may be a setting to keep the update rate fixed or respect the client update rate.

Upvotes: 0

OlegCh
OlegCh

Reputation: 65

Check documentation of OPC DA interface you use to fetch data from the server and what parameters you pass to it.

If you use synchronous reads then problem definitely on server side or its backend (meaning that it takes too much time for server to read actual data).

If you use asynchronous reads (subscriptions) check parameter named like 'update rate'. It defines how often new data will be sent to client. E.g. if it is 1 second client will receive new data NOT faster than 1 second.

Subscriptions are supported by all OPC DA versions. If server doesn't implement this interface you will not be able to read asynchronously and will get error code like 'not implemented'.

Upvotes: 0

Kevin Herron
Kevin Herron

Reputation: 7005

It doesn't sound normal, but it's impossible to say for certain without knowing what the source of the data is.

Upvotes: 1

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