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From Friday, April 19th (11:00 PM CDT) through Saturday, April 20th (2:00 PM CDT), 2024, ni.com will undergo system upgrades that may result in temporary service interruption.
We appreciate your patience as we improve our online experience.
06-09-2009 12:28 AM
I have a basic question about the SVE that I have not found a clear answer to yet in any documentation or white paper:
What triggers the the data transfer across the network from a shared variable engine to a client?
1.The actual "read" operation in the block diagram of the client app
2. a new value written to the variable on the SVE
3. a 10ms timer?
I am trying to avoid un-necessary bandwidth usage on a network and I am very interested in finding out just what triggers a network transfer when using PSP and the shared variable engine. For instance, does the rate at which I read a shared variable in a client app have any effect on network transfer of the data?
06-09-2009 12:39 AM
06-09-2009 11:26 AM
06-09-2009 05:34 PM
Garvacious,
To answer your question(s). The Shared Variable Engine (SVE) does not transmit data across the network unless the client requests it, but the SVE does update on the server side everytime a value is changed on a shared variable. The 10ms buffer that is talked in the article that Mike linked explains how the SVE writes/reads the Shared Variables at a controlled speed to optimize network throughput.
Let me know if that helped clear things up any!