muitl pwm signal input

[marconi 2042]

Do any one know that how many counters do i need to monitoring 12 pwm signal inputs? I am new to PWM signal. Please Help!

[Seth_B.]

marconi,

That will depend on the frequency of the PWM signal you are trying to monitor.  Depending on the frequency, you will need either one or two counters per PWM signal.  I've attached several charts from the NI-DAQmx help that demonstrate what kind of quantization error you will see at certain frequencies on each of the three possible frequency measurement types.  You will need either 12 or 24 counters. Unless you want to add other functionality, like counting the pulses as well as measuring the frequency.  This Developer Zone article explains how many counters are needed for each measurement type.

One Counter - Low Frequency

Two Counters - High Frequency

Two Counters - Large Range

 

Message Edited by Seth B. on 01-20-2009 10:21 AM