Good Morning:
I have a cDaq 9184 and a ni 9401 module: I am trying to measure two frequency inputs to the ni 9401 with values between 100 to 2 Mhz and the software configuration for each is "large range counter" and "frequency" selected for them on the counter vi inputs. The outputs of both insturments are open collector with 5 volt max and the pull up resistor that can range between 100 and 1000 ohms, the signals are connected to pins 14 (PF0) and 19 (PF3) and both commons are connect as well.
The devices are RADIAN Watthour meters and I can see the acutal values displayed and the Radians and the Radians are compared to a national standard and they have errors between +/- 0.02%, However when I am viewing the values diplayed in LabView the errors are bouncing around +/-10% and it appears to be noise. I have tried everything optical coupling, c mos, schmitt triggers with AND gates and nothing appears to work. So, I verified the resistance between pins 14 and 19 and I am measured appoximately 38 Kohms and then measured both pins to common with a resistance of 8.8 Kohms: shouldn't pins 14 and 19 be infinite?
Thanks
Alan