Find latency between two digital input signal raising edge's & falling edge's continuously on multiple samples

[GokulPrasad]

HI, 

I am trying to find the latency between two digital input signal raising edge's & falling edge's continuously on multiple samples. 

Attaching the VI's

tried multiple methods but could not get it 

[Kevin_Price]

What DAQ device(s) do you have available for this?  I'd highly recommend you look into a counter task doing a "Two Edge Separation" measurement if you have a DAQ device to support it.

-Kevin P

[GokulPrasad]

1. i am using cDAQ9185 with NI 9424 (Digital Input) & 9477 (Digital Output), as far as i understand these modules does not support counters. i am using these modules since the Voltage requirement is 24V and these modules supports it.

2. also, i have NI-6363 Multifunction Daq, i read that these does not support voltages greater than 5V. By any chance is there a way to read 24V input using Ni-6363 counters.

3. in addition to the latency i also need to find the max&min of ON time & OFF time of Digital signal

[Kevin_Price]

My cDAQ knowledge is limited, but...

1. Most digital modules *indirectly* support counter tasks by routing digital signals to the chassis backplane which can also be accessed by the internal counters built into the chassis.  Your chassis has 4 such internal counters. 

2.  There are simple logic level-shifting chips that can convert between different digital logic levels, such as 24V -> 5V (and dozens of other options).

3. Counter tasks will be especially useful here.  The 6363 likely supports a convenient "pulse measurement" mode, I don't know either way about your chassis.  But either will support "semi-period" mode, which will yield the same data, but requires a little more manual work in your code to configure and properly handle the data.

    One counter can be used to do your two edge separation measurement.  A second counter can be used to capture a stream of On and Off times that you can analyze.

-Kevin P

[BertMcMahan]

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@GokulPrasad wrote:

2. also, i have NI-6363 Multifunction Daq, i read that these does not support voltages greater than 5V. By any chance is there a way to read 24V input using Ni-6363 counters.

Look up a "resistor divider", this will be very easy to do with a few cents worth of resistors.