Applies To:
  • CitectSCADA
  • CitectHMI
Summary:
When trying to de-tune a system based on RSLinx OPC server by reducing the update rate so that it is longer than 1000mS it does not seem to reduce the load as expected. Even setting 10000 seems to make no difference at all.
 

Solution:
RSLinx has an option in the DDE/OPC Topic configuration. After selecting your particular topic, the setting is on the ‘Data Collection’ tab.

Data Collection Mode – Polled Messages (mSec). The default value here is 1000.

This means that RSLinx will poll this topic at ‘at least’ this rate even if OPC Clients have specified an update rate slower than this. Thus if your goal is to reduce load on the OPC Server or on the PLC by reducing the update rate requested by OPC Clients, you will need to also increase this value.
 
Keywords:
RSLinx OPC update rate 1000  

Attachments