Following up on this thread I seem to have a smiliar question. I have recently taken over a LV project including two cFP's 2120 each with a networked cFP1808 bank. Both controllers have a SVE running serving I/O data to a PC, also on of the controllers has a larger number of "memory" tags (SV) in its SVE. It totals 512 tags on the larger of the two SVE, the other one has 128 tags.
The cFP runs a number of PID controllers (aprox 40) using the PID toolset (reentrant feature disabled on the PID, and integrated errors etc. carried in a shift register - to save memory). The PID app communicates with the local SVE via a VI (labview 2 global) were refs to all SV are opened before the application starts.
To my big horror, I am not getting much speed on the PID controller (due to slow slow slow read/write with the SV) and my question is : How do I optimize this ? Is there an upper limit to how many SV a SVE on a cFP target can support ?, it is best to group similar tags into sub libs inside the main SVE lib ? Any other suggestions as how to increase performance. My cFP has pleanty of memory, but the real time performance is not there, from the PC it can take 1-10 sec. to write to a tag on the SVE of the cFP target, leading the code in the direction of race conditions.
Also, one big problem with SVE on cFP and PID controllers is that one would prefer to run the PID in Engineering units, however with the scaling feature of the SVE on cFP not working - not even after investing in the DSC module, it makes for poor code compared to the dreaded PLC.
Any help is greatly appriciated.
Søren hallberg jensen