Hi all, I want to measure flow rate of liquid oxygen in a rocket engine. It will be measured using the Micro Motion™ 5700 Transmitter (also called Coriolis flow meter or coriolis transmitter) pictured below. I have attached the installation manual. The Coriolis transmitter works by converting raw sensor data to mass flow. This is then translated into an output signal to LabVIEW. The output signal will be in mA as this will be attached to the analogue input module NI 9203 whose signal is measured in amps. To convert the mA output to mass flow that can be displayed on LabVIEW I used the equation below. This is an equation that is used to the determine a 4-20 mA current output from flow rate. I got it from this link: https://www.sensorsone.com/flow-transmitter-4-20ma-current-output-calculator/#inrdg x= (((Linear mA out -4)*(y2-y1))+16y1)/16 Where Linear mA out is the 4-20mA output signal, x is the flow measured by the flow transmitter, y1 is the lowest limit of the flow measured by the transmitter, and y2 the highest limit of the flow measured by the transmitter. The data sheet of the flow transmitter does not specify the lowest flow rate measurement so 0 will be used. However, it does specify a value of 15 g/sec as the highest limit. Thus, flow is measured in g/sec. Now when I applied this theory on LabVIEW I did not get the result I wanted (Vi attached) . I need help. Is this how you would go about measuring flow rate from my coriolis flow meter or am I in the completely wrong direction? Maybe I am using the wrong equation to scale from amps to flow rate? Am I in the right direction but missing something in my vi? Let me know if you need additional details! thanks, Emilie.

Hi erabrannan, in the end all you need is a simple linear scaling: Keep in mind: When measuring current with DAQmx you usually get current in Ampere, so the scaling factors should be corrected to 0.004A and 0.016A. You can also apply a linear scale to the DAQmx channel, so DAQmxRead will already give you "flow" values instead of current (in A).

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Measuring flowrate on labVIEW using a Coriolis flow meter

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Hi,

it seems to be working now!

Again it only works when I set the minimum current to 0 and not 0.004.

Kind regards,

Emilie.

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Measuring flowrate on labVIEW using a Coriolis flow meter

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