9402 Two Counters but Only one being read

[TReesbeck]

I have an NI 9402 with 2 flow meters attached to it.

The flow meters are by Georg Fischer Signet ( 515 Rotor-X and 2100 Turbine Sensor).

They both are hooked up using the "other brand instruments" methodology listed in the user manuals.

I can get signal from the Turbine but not the Rotor-X.

Is there any issues with running 2 DAQ assistants in the same while loop and trying to record edge counters with what I have said so far?

I will be expanding upon this tomorrow with simplified code and relooking at the wiring.

Thanks,

-Tom

[TReesbeck]

Hardware:

NI cDAQ-9184

NI 9211

NI 9402

NI 9207

Georg Fischer Signet 515 Rotor X Flow Sensor (High flow)

http://www.gfsignet.com/go/C10FA90D19993E1D34F720FD99FA3EE7?action=GF_DocumentDownload&doc_uuid=C10F...

Georg Fischer Signet 2100 Turbine Sensor (Low flow)

http://www.gfsignet.com/go/5216219519993E1D4B86FF18C39A1DCD?action=GF_DocumentDownload&doc_uuid=5216...

Wiring:

I have the ground and Input of the other instrument hooked up to the BNC port of the NI 9207 counter.

I have a power supply set at 5 volts providing DC power to many of my instruments requiring it.

I have the wires hooked up the same way for each flow sensor.

Only the Turbine sensor has been able to send a readable signal.

I have used the frequency measure setting on a multimeter to read the signal from each and both ouput a signal.

The Rotor X is a paddlewheel sensor and puts out a highly fluctuating signal.

For my code, I used seperate DAQ assistants for all 4 ports on the NI 9207 because for some reason the labeling of channel 0 does not always go to port 0.

Almost everytime I have run the test the Turbine sensor works and the Rotor does not.

There was one test where both were collecting, but I assume it was a false trigger when I was wiring & re-wiring.

I will be rechecking my wire diagram.

If anyone sees something obviously wrong going on please let me know.

Thanks,

-Tom

[falkpl]

I dont use daq assistant often, but I believe each counter is run in its own task (unlike analog where you can add multiple channels to a single task) and since you might be reading the asynchronously, you could try to run in seperate loops.  There are many synchronization techniques to get the data back to tour ui loop (queues producer consumer, functional globals).

[TReesbeck]

After testing the signal and many things, it is not on the Labview side.

This problem is on the hardware side.

The flow meter isn't spinning at all for the flow rate we are running it when with water.

The signal works when we send air through it or move the paddle wheel.

The system with the back pressure doesn't work with the paddle wheel.

We are running it at 1 to 1.5 GPM, and according to the flow rate calculations it's lower limit should be 0.8 GPM.

I am uncertain of why it doesn't work, but I will have to let it go and continue with the project.

If anyone has worked with paddle wheel flow meter's and can lend some advice, I would be much obliged

Thanks and sorry for the confusion.

-Tom

[TReesbeck]

Back to the drawing board . . . .

Hardware:

NI cDAQ-9184

NI 9211

NI 9402 (http://sine.ni.com/nips/cds/view/p/lang/en/nid/209905)

NI 9207

Georg Fischer Signet 515 Rotor X Flow Sensor (High flow)

http://www.gfsignet.com/go/C10FA90D19993E1D34F720FD99FA3EE7?action=GF_DocumentDownload&doc_uuid=C10F...

Georg Fischer Signet 2100 Turbine Sensor (Low flow)

http://www.gfsignet.com/go/5216219519993E1D4B86FF18C39A1DCD?action=GF_DocumentDownload&doc_uuid=5216...

The Signet 2100 always works.

The Signet 515 has never consistantly worked. I have 3 of them and they operate fine.

They send a frequency signal out of 2 wires as seen in the image.

I have hooked the Black and Red up to BNC connector to the 9402 port 0 using this part (http://www.mcmaster.com/#6704K14).

I then go to labview and try to read the frequency coming from the Signet flow meter.

The reading times out or always reads 0.

After reading the forums about frequency measurements. I need to connect it the the PFI port, but I am uncertain of what that means for the 9402.

Can someone please tell me if it's my wiring or my programming that is the issue.

Thanks,

Thomas