Gems-FT110 series flow rate sensors

[tran88]

Hello, 

I have only been working with DAQ and LabView for 3 weeks as a school project.

I have a Gems-FT 110 flow rate sensor, and attached is the spec sheet that comes with the sensor. From the spec sheet, the sensor is giving out readings in frequency. My receiver is NI USB DAQ 6001, and in order to pick up frequency I have to set my daq assistant as digital input. The wiring connection I currently have for the flow rate sensor is positive goes to the 5V port of the digital side of the daq 6001. Negative wire of the flow rate sensor goes to the Ground port of the digital of the daq 6001. And the signal wire goes to the PFI 0 (which is the port 2 of digital input). However, I do not have any readings at all. Please correct me or give me some guidance over this. 

Thanks,

Anh T. 

[AnalogKid2DigitalMan]

Did you install the pullup resistor as shown in the datasheet?

-AK2DM

[tran88]

Yes, I have installed the pull up resistor (4k Ohms). After some modifications of the wiring set up, such as the positive of flow meter goes to positive of power supply, negative of flow meter goes to negative of power supply, and signal of flow meter goes to the port0/line0 of DAQ-6001, and another wire from positive of power supply goes to port 5V of DAQ-6001. The wiring instructions are from NI for digital input when you have a sinking-output device (flow meter) example of sinking output device is NPN open collection, which is the exact same thing like the flow meter. (I have attached the wiring diagram as well). I was able to get the green LED light after I hit run in the DAQ Assistant. I believe the green LED light is telling me that there is signal travelling thru or it is trying to communicate with the DAQ. I have my LabView code set up as in the attachment. (I have provided below a link to NI where they explain in details what the green LED means).  When I click run LabView VI, (I have no errors at all, the LabView does run continuously) as you can see on page 5 of the attachment, even with the water running through the flow meter, I still do not have readings. Please let me know what else can I do? 

Link to NI: https://www.ni.com/getting-started/set-up-hardware/data-acquisition/digital-input

Thanks,

Anh T.