What is the meaning of CTR 0 SRC , CTR 0 GATE

[R_J]

Hi All

Plase tell me what is the meaning of CTR 0 SRC , CTR 0 GATE, CTR 0 AUX , CTR 0 OUT , CTR 0 A , CTR 0 Z , CTR 0 B.  What is the difference between them , in terms of their use. Where we have to require these lines ?

I have to count the pulses & also measure the pulse width. Which lines i have to use.

Regards

J

[Ima U]

Hi J,

If you look on page 177 in the M Series User Manual you will see that CTR 0 SRC is the same as CTR 0 A. CTR 0 SRC is the source of counter 0. You connect the signal you are counting to the source. CTR 0 GATE is the same as CTR 0 Z. CTR 0 GATE is the gate of counter 0. When the gate is high the pulses entering on the source will be counted. CTR 0 OUT is the output of the counter 0 and CTR 0 AUX is the auxililary line of counter 0.  You use CTR 0 AUX to determine if the counter counts increments or decrements. For a better explanation you should read through this post.

Assuming you are using LabVIEW to write this application, there are example programs that count pulses or measure pulse width.  You can find them by opening LabVIEW and going to "Find Examples" in the Help menu.  This will open the NI Example Finder.  Under the Browse Tab go to Hardware Input and Output >> DAQmx >> Counter Measurements >> Period or Pulse Width. 

I hope this helps!

[pedrorivera]

hi, i want to ask you something, if i want to measure a digital signal's frecuency i have to connect my signal to source CTR 0 SRC, and put CTR 0 GATE in high when i want to measure?, can i trigger the count acquisition in my labview code?

thanks for help 

[JB]

See the examples and let us know if you need further help.

For LV 2011 :

LV menu >> Help >> Find Examples... >> Hardware Input and Output >> DAQmx >> Counter Measurements >> Digital Frequency

[pedrorivera]

i read m series user manual and i read de low frequency acquisition example, what i want to know is how to connect my signal, in this case, m series manual says my signal is an low frequency (0 to 100 hz) and i have to connect my signal to gate terminal (ctr gate pfi9 in ni pci 6221) but there says that i have to connect to source (ctr src pfi8) a timebase signal, faster than my signal, but when i use daq asistant.vi, says that i have to connect only one signal, the measured signal.

i want to use an internal timebase signal if its possible.

thanks for help.

ps. i tried this acquisition with daq asistant.vi and there is a fail, frequency measures go up to 8khz (bigger than i expected) i want to ask if noise at signal affects too much the measurement, if u can share documentation about how this acquisition are designed ill apprecitate it.