How to count the source or gate input?(please help me)

[yao_yong]

In our lab,  we have a DAQ 6259 and some people made a C++ program to control it. Now I want to use labview. But even I use the example from the sofeware(Count Digital Events.vi), it cannot get the counts. However , if i test the channel in max , the edge source must be gate input. Who knows the reason? Please help me ?

 http://forums.ni.com/t5/Counter-Timer/daq-counter-using-gate-input/m-p/1782362

Best wishes

Yao 

[Kwok_How]

For your information, source is an input signal that can change the current count stored in the count register. The counter looks for rising or falling edges on the source

signal. When an active edge (either rising or falling, software selectable) is received on the source signal, the count changed.

Meanwhile gate is an input signal that determines if an active edge on the source changes the count, and it allows you to acknowledge or ignore active edges on the source.

Right now, I can't see a reason why you can't use the PFI8 as the edge source. Can you try it on the counter 1 and change your edge source to PFI3 (CTR1 SRC)?

[pedrorivera]

hi, yao yong, you should read about the configuration you are choosing, the only situation i have seen about using a gate terminal as a input pin is when you signal is too slow and you're measuring frequency, you should try what Kwok How says about try counter input 0 or try daq assistant.vi

Kwok How, i want to ask you or someone else if edge count or frequency measurement recognize every edge ( like noise-generated edges ) or just edges between 0 and 5 volts

best regards

[yao_yong]

Thank you for your reply. The gate signal is random, in this case , how to determine the rate of the count channel?