response time for several steps increases

[G1L]

i have two signals adquired at the same time, signal A command signal B and i need to measure the time it takes the signal B to change from its initial commanded value to 90% of the difference between its initial and final commanded value and measure the overshoot and preshoot for each step given



i know the amplitude for each step for signa A and used these to find trigger locations, used the index for each trigger location to get an amount of data from the signal array, with "Transition Measurements.vi" i get the start times, the difference between these is the response time

i have no idea about how to get overshoot and preshoot values, i hope somebody could help me

and if you know a better way to get the response times, please tell me 😉

thanks in advance

Message Edited by G1L on 03-23-2007 01:09 PM

[Erin_B.]

Hi G1L,

The preshoot and overshoot value calculation is explained in the Help for the Transition Measurement VI.  Just right-click over the function and select Help.  I ran your example and added indicators for those terminals, and they return values.  These values are based on the high and low reference levels that are calculated for each waveform.  I'm not sure if they are what you were expecting.  If they are not, I would recommend looking that the Measurement Info. output and checking that the High/Low reference levels are the correct values.  If not, you may want to consider passing the values manually for each voltage level, or acquiring more data for each level to provide a more precise calculation.  Hope this helps.

Regards,

ErinB.

NI Mexico

[G1L]

Hi Erin,

i think one problem is with my data, i have five archives and signals changes in each one, another problem is the width and amplitude of each step is variable (i'm working with fixed values, but them would change ). There are two steps missing, the firs and the last, both equals to 0.2 i have considered this.

i done what you said, cheking the "Show Context Help", looking for examples in "Find Examples...", and search in the forum is the first thing i did before post...

i will consider to get more data files, thanks