What I do to configure DSC to read and log 5000+ tags?

[Bruno Costa]

Hi,

I'm developing a application thats need read and log a large tag database at period of 1 second. My system have actually 1200 tags and when I try to increase the number of tags my system slowdown and not update at requested period anymore.

I'm using NI OPC Servers to read data of 4 different PLC's. In the SVE I've created an IO Server to bind variables and all variables are located in a single process.

All variables are logging alarms and data. The Log Deadband and Update Deadband are set to 0.

My machine is a DELL Precision T5400 with Dual Intel Xeon Quad Core with 4GB of RAM and Windows XP Sp3 installed.

LabVIEW 8.6.1

Bruno Costa

Automation Enginner

[crelf]

When you say "read and log", I assume you don't mean you're reading from one database and logging the data to another, right?

We've had success reading that number of channels, but it often depends on the hardware. If you can get the data from the hardware in that time, then you're probably okay (the database writes aren't too timeconsuming).

[Bruno Costa]

When you say "read and log", I assume you don't mean you're reading from one database and logging the data to another, right?

We've had success reading that number of channels, but it often depends on the hardware. If you can get the data from the hardware in that time, then you're probably okay (the database writes aren't too timeconsuming).

I want say read tags from PLCs and log in database. This operation isn't tima comsuming because i use only 2% of CPU time.

Wich version of LabVIEW are you using? Update rate, deadband ... . I want know what you doing different, to make it work.

In attached image you can see the system layout.

[Louis Philippe Girouard]

Hi,

I'm developing a application thats need read and log a large tag database at period of 1 second. My system have actually 1200 tags and when I try to increase the number of tags my system slowdown and not update at requested period anymore.

What is the update rate of every Tag in your OPC Server? They should all be at 1000ms, if it's lower, there is a chance you are logging a lot more data than you need since your Shared Variables deviation is set to 0.

If that doesn't do it, I would suggest increasing the deviation to minimize logging small changes in data that might not be of any use anyway.

The SVE is not the most efficient application when it's asked to perform a lot of operations quickly. If you minimize how often each channel updates, you will reduce the load on the SVE and therefore allow it to handle more channels.

Good luck,

LP.