differentiation in labview

[yaauldgoat]

hi
i have been using the differentiation block in Labview but unsure how to connect it. I am placing the sigal I want to differentiate in at X in the VI Derivative x(t) and using the output dx/dt. but how do i relate time to this block? i need differentiation within a while control loop.

[Dennis_Knutson]

You need to set dt equal to your sampling rate. In one of your other posts, you said you were using the DAQ Assistant. In there, you specify how many samples per second to acquire. Set your dt to the same value.

[yaauldgoat]

hi,
i was using the daq assistant but am now using daqmx vi's . do i connect dt to the clock? at the moment i have it connected to 1000 to be the same rate as the clock

[rpursley8]

Since the clock rate is 1000 Hz and Hertz is 1/seconds you will need to invert the value to get dt in seconds

[DFGray]

Be careful with that VI. It is very susceptible to noise. You may want to check out the following thread for ways to improve it:

http://forums.ni.com/ni/board/message?board.id=170&message.id=102065#M10206