Flow Meter using labVeiw

[emma.lex]

hey 

I am a relatively inexperienced LabVIEW developer, so while I will do my best to provide all the necessary information, if something is missing or unclear, i am so sorry.

I am attempting to read the output of an Rs 256-225 flow meter in LabVIEW, and write the flow values to an Excel file. To do this, I am using a USB-6008 DAQ board (with 9.3.5 drivers) and LabVIEW 2010 on a Windows 7 64-bit machine. The data sheet.  The flow it can measure is 0.02-0.9 L/min of water. The flow meter requires 4.5-24V DC, and I am powering it using a generic 24V power supply, which I believe (based on testing with a multimeter) is working. i have a 3 wires system which is capable of outputting a  0-10V analog voltage signal or a 4-20mA current signal, depending on use. I am finding it hard to come up with a working program. 

In theroy i think i only need it to read out the output voltage or current and the input the voltage. Also i would like to be able to control how much flow i want.

My wiring is as such:

Pin 1 (Red Wire): Positive Power Supply

Pin 2 (Blue Wire): This i want to be my output which i think is going to be an anolog  

Pin 3 (Braid wire): Negative Power Supply

Thanks 

[GerdW]

Hi emma,

according to the spec sheet for this obsolete product it has an open collector output (with an internal pullup resistor) giving you pulses.

You should use the CTR input (PFI0) of the USB6008 to count those pulses, but be sure to limit the voltage as the USB6008 likes to use TTL level signals (when I remember this right). From getting pulses per second you can easily calc flowrate in l/s or l/min…

Using the CTR is much easier than using AI and analyzing the signal to count pulses on your own!

[emma.lex]

This will sound like a stupid question but how would you go about using the CTR (PFI0) of the USB6008

thanks for the help so far

Emma

[GerdW]

Hi emma,

LabVIEW comes with a lot of example VIs! There are VIs demonstrating the usage of Counter capabilities of DAQmx devices…

[tallita_nunes]

Dear.

I need to use a flow meter (manufacturer Omega, model FPR-303).

This flow meter has three cables: red, white and black.

According of the Omega, the red is the sensor power supply (5-24 V DC and 2 mA current), white is the signal and black is a ground.
The sensor`s output is current sinking pulse (6-24 Vdc), the sensor input on PLC can accept a current sinking device and the PLC frequency response > flow meter output frequency.

My plan was use the NI USB-6210 to edge count and determination the flow according with factor-k that i obtained by manufacturer.

I read the USB-6210`s manual and connected the red in +5V, white in FPI 0 for crt0 and black in DGND, all of the wires in Digital I/O side.

I have tried to use the NI USB-6210 on my Labview SignalExpress.

In Labview SignalExpress i did: Connected the NI USB > Add step > Adquire Signal > DAQmx Adquire > Counter Input > Edge Count. I choose the falling active edge and Sample On Demand.

I have tested the NI USB-6210 and flow meter, but i do not have success.

Is NI USB-6210 applicable in this case?
If it is not, please, tell me the appropriate equipament.

Regards.
Tallita Nunes

[Dennis_Knutson]

Please repost your question to the SignalExpress board. This is the LabVIEW board and not many people here use your software. But, yes, the 6210 should be an appropriate device.