ure at the same time frequency AND duty cycle. How can I accomplish it with a PCI-6035E card? Maybe using both counters together? (I would prefer not to use an analog channel to aquire the signal 'cause all inputs are used by other signals I need to study)Roberto,
You can do this using examples that ship with NI-DAQ (LabVIEW\examples\daq\counter or NI-DAQ\examples\
\ctr) If you do not have the examples on your machine, you can install them by running NI-DAQ Setup and selection support for your developement language. You will need to use both of the counters on your 6035E. On counter 0, you should do Buffered Period Measurement. On counter 1 you should do Bufferd Pulse Width Measurement. By knowing your period, you can invert that for Frequency. You can divide Pulse Width by Period to get Duty Cycle.
In both cases, you will want to connected your signal to the gate of the counters and use the SAME internal timebase for the sourse of both counters. By using Buffered modes, each time a signal comes in on t
he gate, a new value is latched into a data buffer. This ensure that your period and pulse width measurements are made at the same time. You can then read out the data and process it.
Nick Wilson
Application Engineering
National Instruments
www.ni.com/ask
