NI USB-6343 Counter Measurement Issues

[LVIEWPQ]

I feel like I've tried everything, so I'm asking for some advice on how to set this up now. 

I want to be able to read all four channels, ctr 0, 1, 2, 3 on quite a simple source (single wire output flowmeter)

I can't get any of the channels to read, so I'm stripping back to how to do it with 1 channel, and then replicating for the others. 

ctr 0 uses PFI8 (Pin 81) as the source. I have connected a signal generator to PFI8 (Pin 81) running 50Hz 1V amplitude peak to peak.

My settings in NI Max are attached below. Looking for suggestions please. 

[AnalogKid2DigitalMan]

Digital I/O's on that DAQ are TTL compatible (o-5V), so 1V P-P will not be detected.

https://www.ni.com/docs/en-US/bundle/usb-6343-specs/page/specs.html

What is a single wire flowmeter? Can you provide make/model and the specifications along with how you wired them up to the DAQ?

-AK2DM

[LVIEWPQ]

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@AnalogKid2DigitalMan wrote:

Digital I/O's on that DAQ are TTL compatible (o-5V), so 1V P-P will not be detected.

https://www.ni.com/docs/en-US/bundle/usb-6343-specs/page/specs.html

What is a single wire flowmeter? Can you provide make/model and the specifications along with how you wired them up to the DAQ?

-AK2DM

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These are the flowmeters we are using (or at least the closest style I can find, I'm working with very poorly documented legacy hardware) 

https://docs.rs-online.com/7c18/0900766b8023e8dd.pdf

Looks like I need a different signal generator then, the one I have only does 2.5 each peak.

In terms of setup I then need an appropriate resistor across the ground and signal wire to generate the correct output? 

[AnalogKid2DigitalMan]

Can your generator supply a 0V to 2.5V signal (not going negative)? If so that might work on the DAQ inputs:

https://learn.sparkfun.com/tutorials/logic-levels/ttl-logic-levels

Power the meters with 5VDC you will need the pullup resistor between 5V on pin 1 (not ground) and the output on pin 2.

-AK2DM

[Kevin_Price · Accepted solution]

Assuming (based on your user name) that you're using LabVIEW, try this very slight mod from one of the shipping examples for generating a continuous pulse train with one of your counters.  The mod allows you to modify the frequency on the fly without stopping the output.   You can temporarily use this in place of your flow meter and signal generator to be sure you have a "known good" TTL-compatible signal source as you debug your code for measuring frequency with ctr0.

-Kevin P

[LVIEWPQ]

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@Kevin_Price wrote:

Assuming (based on your user name) that you're using LabVIEW, try this very slight mod from one of the shipping examples for generating a continuous pulse train with one of your counters.  The mod allows you to modify the frequency on the fly without stopping the output.   You can temporarily use this in place of your flow meter and signal generator to be sure you have a "known good" TTL-compatible signal source as you debug your code for measuring frequency with ctr0.

-Kevin P

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Thankyou for this. Exactly what I needed. Now happy that things are working with a known good source.