Delay values for large data, buffer?

[CANewbie]

Hello,

 

I think this topic is very important for everybody that are doing advanced DAQ. Because it you want to save an event, you need first to see it(real time analysis), and than to save the transition how the event happened(that means to have values, before the event happened). Using consumer producer structure.

 

i'm trying to save data into some kind of buffer. my main goal is to delay values. I successfully created a delay using Delay values.vi, the problem is i think it makes the while loop slower. If anyone knows what is a good practice to create a delay for large amounts of samples 100k, 200k, 300k samples? Is a delay values.vi good practice, or is there another better way?

 

Thank you

[bbean]

Use no delay and this

Circular Buffer:

https://lavag.org/files/file/250-circular-buffer/

[CANewbie]

Tnx for the reply

So if i understand correctly. I still use consumer producer. In the producer there is only DAQ blocks that fill up queue. In the consumer loop i can than use circular buffer and later save the data?

[ShaunR]

What is the data rate?

 

There is an example of using a fast DB for infinite history data logging..

 

[bbean]

Tnx for the reply

So if i understand correctly. I still use consumer producer. In the producer there is only DAQ blocks that fill up queue. In the consumer loop i can than use circular buffer and later save the data?

 

You can still have a producer/consumer loop if you want.  The nice thing about Hoovah's circular buffer is that its DVR based so you could spit the wire and read the data in parallel if you want.  

 

I haven't seen your code and do not know how you want to trigger the save data.  Do you need to analyze the whole buffer every iteration to determine whether to save or are you doing something like just triggering on a rising edge level and only need to look at each daq read chunk?

 

You can probably do all the DAQ reading/triggering/saving in a single loop if you use pipe lining.  But I can only speculate unless you attach code.  A crude example using the Circular Buffer Demo.vi as a starting point: