Real-Time Measurement and Control

cancel
Showing results for 
Search instead for 
Did you mean: 

PID control with data saving

Hello,
 
I am trying to make a simple PID controller for a rather slow process (loop rates < 1000 Hz), so I thought that I would just use a simple Labview VI (without realtime module). This seems to work fine and fast enough, but I would also like to save the input signal and the controller output to a spreadsheet or binary file to be able to analyse the performance of the controller.
 
I tried to add a 'write to spreadsheat' sub VI inside the controller loop to write the successive data values to a file (I used the append option to ensure that the previous values are not overwritten), but this limits the maximum loop rate to about 100 Hz. Does anyone know have a better idea? Maybe a VI alrready exists to do this?
 
Thank's a lot in advance!
 
CU
Peter Mercelis
0 Kudos
Message 1 of 3
(3,395 Views)

Hello Peter,

If I'm nog mistaking this problem is resolved in the meanwhile on your other post, correct?

http://forums.ni.com/ni/board/message?board.id=170&message.id=181201

Regards,

Wouter Van Hoof
National Instruments

0 Kudos
Message 2 of 3
(3,382 Views)

Hello,

the problem is solved indeed (by opening the file only once, before the while loop and closing afterwards). Thanks anyhow.

CU

Peter

0 Kudos
Message 3 of 3
(3,379 Views)