Pulse count - Flow Meter

[JCuneo]

Looking to for help to count the pulses in a while loop, any suggestions? 

The signal seems reasonable, I just can't figure out the logic and would appreciate a push in the right direction.

[santo_13]

You didn't mention the HW you're using to count pulses and did not share any code that you already have to provide any sort of help.

[altenbach]

• What does counting pulses have to do with a while loop?
• What is the signal (voltage? light?, etc.)
• Do you want to keep count as new pulses arrive or process an existing waveform?
• Are you using a plain analog input? A counter?
• What are your time units?
• What is the typical width of a pulse? A nanosecond? A second?
• Do you need the count for derived units, e.g. display of RPM?
• Are you interested in the total count or counts per time unit?
• ... so many questions!

[JCuneo]

Hi Santhosh,

I’m using a Keyence FD-Q flow meter:

https://www.movetec.fi/images/pdf/AS_79677_FD-Q_C_600I65_GB_WW_1058-3.pdf

I have no code, all I’ve done is wired in the sensor to the DAQ. I’ve just plotted the signal for reference. I’ll take a snap shot on Monday - however all you’re seeing is a AI channel in a loop recording the test signals. 

[JCuneo]

Hi Altenbach,

• What is the signal = voltage
• Do you want to keep count as new pulses arrive or process an existing waveform - I’d like to get the total accumulated pulses, I’m trying to track total consumed product where one pulse is 0.5L
• Are you interested in the total count or counts per time unit? - total count 

I’ll try and answer remaining questions Monday - I appreciate your support. 

[JCuneo]

I grabbed an edge counter, how can I increment the value each time the edge rises and falls?

The signal is just voltage where the flow meter throws +10V every time it detects 0.5L passing through the system. 

[altenbach]

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@JCuneo wrote:

I grabbed an edge counter,. 

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I probably would not call that a real edge counter? In what dark corner did you find that?

[GerdW]

Hi JCuneo,

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@JCuneo wrote:

I grabbed an edge counter, how can I increment the value each time the edge rises and falls?

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Where did you "grab" that "edge counter?

Why not start with a more simple approach using functions provided by NI?

I count only rising edges in this snippet (that's how flowmeters work in my experience), but you can easily switch to count both edges using the BooleanCrossing function…

[santo_13]

You mentioned that you hooked it up to a DAQ but didn't mention the model.

If the DAQ has a counter input you can directly use that feature, it accumulates the counts which is what you're trying to achieve.

Only concern I have is that the counter input are digital and typically 5V, since your flow meter is 10V you might need to put a resistor divider or an optocoupler to protect the DAQ inputs.