04-15-2015 06:26 AM
Hi, I am generating sinewave using function generator and acquirng this into my computer using DAQ USB6211 and labview DAQassitant. I want to manipulate this acquired singal using the labview PID control and use the output of PID to generate an feedback analog singal (similar to the input one). But when I run the code, it gives me an error that the buffer size is less. How do I increase the buffer size so that I can generate the output singal continuously. I have attached the .vi file
Thanks a ton.
Krishna
Solved! Go to Solution.
04-15-2015 06:34 AM
Hi Krishna,
get rid of the DAQAssistents and use plain DAQmx functions!
It's never a good idea to use DDT wires in combination with coercion dots: what kind of data does your DAQAssistent deliver and what does your PID expect?
04-15-2015 07:02 AM
Hi GerdW,
Thanks for your prompt reply. This is my first program that I am writing in labview. I have written now a code for acquiring the signal (without DAQ assistant). I am trying to find way generate signal using PID loop. I have attached the incomplete .vi file.
The need simple proportional amplifier to amplify my input singal but keep the waveform same. Since PID gives a single value at the output I am facing this issue.
Regards,
Krishna
04-15-2015 08:29 AM
Sorry here is the right version attached.
04-15-2015 09:15 AM - edited 04-15-2015 09:26 AM
Hi Krishna,
The need simple proportional amplifier to amplify my input singal but keep the waveform same.
Why do you use a PID when you want to amplify your signal?
Why not use a simple multiplication instead?
The VI in your last message shows several problems:
- there is no loop, so it executes just once and stops immediately…
- there is a DAQmxWrite-function with no DAQmx task wired in - it will throw an error!
- you really should use the autocleanup tool more often!
- you still feed the PID with a waveform - it does not work with waveforms!