Why is the apllication becoming slow

[hema]

I am using DSC version 7.0 and have connected about 25 tags in tag engine to PLC
and siemens drive. I also have about 15 tags connected directly through data socket.
The problem is that when I run my application it becomes very slow and sometimes the
PC also hangs. When I run this application with memory tags, there is no problem.
PC has 256MB RAM and clock speed 1.33 GHz.

please help..thanks

[Remzi]

Hi,

Are you using National Instruments IA OPC server or a third party OPC server to access the PLC tags. Are you using HMI Wizard or Front Panel Datasocket Connections in LabVIEW? On the windows Task Manager, which application takes the CPU and memory resources more?
Regards,
Remzi A.
Applications Engineering
National Instruments

[hema]

Hi Remzi,

I am using OPC Simatic NET Server. that is third party
OPC server.
I am using Front panel datasocket connection and not HMI wizard.
What exactly is the difference betweem HMI wizard and data socket connection. On the windows task manager, i see LabVIEW and dsc engine when i do CTRL+ALT+Del.
And also if i run my VIs individually there is no problem.
But when i use my Vis as SubVis and try to navigate to and fro, it takes time for the VIs to open.
Do i have to install DSC Run time Engine CD also.
Pls help. Thank you,
Hema

[Remzi]

Hi Hema,

If you want to improve the performance of your application, use HMI wizard to connect to OPC tags instead of Front Panel DS connection. This method can handle high number I/O points more effectively then front panel DS connection method. Another reason of slow performance might the OPC server itself. When you say "slow", do you mean the update rate is slow? or launching the VI for the first time is slow? You can use Server Explorer to connect to the OPC tags and then check if there is any problem with accessing the tags through Server Explorer. By the way, you do not need to install DSC Run-time

I hope this helps.
Best Regards,
Remzi A.

[Dr.Conway]

Hello.

i am also having problems with the update rate of my VI. it takes approx. 3secs for the front panel to update, which is much too slow. i have a wait instruction in my while loop of 250ms. i tried to lower this to 100ms but this only made it worse. would it help if i change the polling time of the tags? i am using the kepware opc server to connect to an omron plc.

regards,

Andrew