Real Time maximum loop speeds

[schpongo]

I'm still new to LV and have a question about the achievable loops times on the RT system on a cRIO 9074.

From what I've understood, the maximum loop rate for a loop containing elements which access the scan interface is 1000 Hz .

But can you run a loop faster, when it does not use the scan engine to access anything.

Thanks for the help.
Daniel

[schpongo]

I'm still new to LV and have a question about the achievable loops times on the RT system on a cRIO 9074.

From what I've understood, the maximum loop rate for a loop containing elements which access the scan interface is 1000 Hz .

But can you run a loop faster, when it does not use the scan engine to access anything.

Thanks for the help.
Daniel

[GerdW · Accepted solution]

Hi Daniel,

yes.

Spoiler

When you want to achieve loop iteration rates in the kHz-range including HW access you should start to program the FPGA part of your cRIO9074!

[schpongo]

Thanks for the quick answer. 
What kind of loop rate would I be looking at?

[GerdW]

Hi Daniel,

achievable loop rates depend on loop content and CPU resources…

What exactly do you want to process in those loops?

- You have a CPU clocked at 400MHz (or was it just 266MHz?) and there still is a OS running in the background.

- You surely don't want to hog the CPU so the whole cRIO becomes unresponsive.

Btw. you don't need to post your question twice, please keep your discussion in one place.

[schpongo]

I have a 400MHz CPU.
You are correct I don't want to overly stress the cpu. But I'm just trying to get a feel for the speed as I don't have access to the unit on which my software should be deployed.

I'm sorry for double posting the Question, but I was getting errors while trying to post the question and must have accidentally posted the question twice.

[GerdW]

Hi Daniel,

I'm just trying to get a feel for the speed as I don't have access to the unit on which my software should be deployed.

To get a feeling about the processing speed of your cRIO you could use an old PC with a PentiumII CPU from 1998/1999. This old CPU used about the same clock!

You need to understand the meaning of the term "realtime": it has nothing to do with raw processing speed! Your cRIO is an older device with very limited processing power (CPU and RAM)…