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Running a PID loop at high speed (100hz+) ?

Using the target monitor tool, late arrivals start happening if I get above about 20hz. Any other suggestions?

I don't need to be receiving data to the gateway for logging any faster than 10hz, the only thing that needs to be happening fast is the PID loops.

Right now I am also pursuing adding another target (crio) to handle the PID work, but that is turning into a nightmare in and of itself to get data between targets and to get veristand to run on it.

I hate to sound negative but we're getting pretty close to shutting the door on veristand and going back to a homebuilt labview .vi. At this point it seems like it would be easier than the endless custom devices/software and limitations that seem to accompany everything veristand.

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Message 11 of 14
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Hm, that's a bit odd. It sounds like you might have a different underlying issue besides the thermocouple timing.

 

Have you checked the CPU usage to make sure the system isn't being overloaded?

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000P9kJSAS

 

Have you tried making a simple project with just the PID model and seeing if that runs at 100Hz?

 

You'll probably want to narrow down why your seeing late arrivals first, but if you want to keep most everything running at 10Hz and be able to adjust the PID rate, Emboar's suggestion of a custom device is probably the best option.

Bill B.
Applications Engineering
National Instruments
Message 12 of 14
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So to me it looks like I can set the TC cards to "Slow background conversion rate" enabled at 10hz and I can run the target at 1000hz, at least it seems to be working so far? This seems like too obvious of a solution though and I'm skeptical that nobody suggested it already?

Message 13 of 14
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Sounds like this was the silver bullet for this issue. What you're describing is the intended functionality for the 'Slow Background Conversion Mode'.

Message 14 of 14
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