data trend finding?

[data logging]

i want to stop my data acquistion on the basis of data being taken from teh daq 

now my voltage curve would be increasing in one cycle and would be decreasing in the othere cycle

i need to apply diffenert conditions for both

i need to find the data trend for it

that the data is increasing or decreasing

may be finding the slope of line would work (sign of solpe would change with increasing or decreasing curve)

i cannot take just the difference of two successive ppints as there can be surges in the data reading process

tell me what to do now

how to fine the data trend 

and how to implement condtion on the basis of data trend

[JVP]

Hello,

You want to take a look at each individual windows of samples rather then single samples. I would like for you to take a look at two of the Developer Zone Articles: Analog Resource Center and Software filtering: Windowing - General Analog Concepts.

Best Regards,

Jignesh P

[data logging]

i donot want to take the FFT or any frequency domain analysis.. may be your idea is good.. but i just want to find the slope of may be  50 points. if the slope has negative sign then the voltage is decreasing and if the sign of voltage is positive the voltage is increasing......