How to start data acquisition when a sine wave starts or finishes

[Portugues]

I am using a DAQ-1200 to analyse three waveforms, I need to start acquisition when any of the sinewave changes from zero to start and when it stops. However, I also need to some 600 samples before the triggering occurs and I do not know how to do this without causing a delay, can anyone help me please?

[Ben]

Dennis answered this in LV general

http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=5065000000080000000F3C0000&UCATEGORY_0=_49_%24_6_&UCATEGORY_S=0

Ben