Can Rpi read mass flow meter ?

Question

I am considering purchasing a coriolis mass flow meter that emits pulses for a project. I know it is quite common to read volumetric flow meters with the pi but I cannot say the same for the mass flow meter.

Now my question is this; if I purchase the coriolis meter, will I be able to hook it up to the pi as easy as the common flow meter and write code to determine flow rate and volume ?

Problemchild · Answer

Is this this an automotive MAF sensor? As I remember many of those are a resistor bridge with one arm in the Air flow, in that case it's a process of measurement of how out of balance the bridge becomes and that's an analog problem.

If you want to ensure you can read Pulses/Pulse rates or analog voltages at a fixed reliable rate I would consider using one of a million controllers then offering it up to the PI for high level processing since you wouldn't need to worry about Linux latency issues presuming they are even an issue with your solution!

Answer is yes but you'll need to elaborate on what you are doing !

netromaster · Answer

It is not an automotive MAF sensor. It is a double tube coriolis meter for basically water and oil measurements. It does have a local interface showing massflow and volume readings. I plan to extend its features with my own controller to help me remotely get readings. Basically making it IoT complaint. Its is a generic flow meter with no claims on it.

clem57 · Answer

Since I did not know, I post this for others to learn: Coriolis mass flow measuring principle. The operating principle of a Coriolis flow meter is basic but very effective. ... When a fluid (gas or liquid) passes through this tube the mass flow momentum will cause a change in the tube vibration, the tube will twist resulting in a phase shift. For more details see https://www.omega.com/en-us/resources/what-is-a-coriolis-flow-meter Clem

netromaster · Answer

Yes, a local interface with an LCD. Its a generic meter.

colporteur · Answer

Your post reminds me of what I call white boarding. Techie's sitting around hashing out a solution to a problem. One of the few pleasures I miss now that I am retired. In our enthusiasm to select technology, what feels good to us may not be the best. A Doug dougw points out the pi is less than ideal for project requiring realtime response. That doesn't make it bad but maybe not a good as a device that has a better realtime response. I have tracked responses to my inquiries and any information I have would just be noise. Sean

mp2100 · Answer

As John said, the short answer is yes. But whether the rPi is the best solution is a follow-up discussion. Does the manufacturer tell you how fast the pulses are generated at normal flow? The rPi is a Linux computer, so if pulses come very fast, it may be busy doing other Linux operating system things when it should be counting pulses. A simpler microprocessor could be better for this than the rPi.

An alternate route could be, if the coriolis meter supports modbus, there are modbus libraries for the rPi. You'd use the UART serial pins to talk Modbus.

netromaster · Answer

Oh yes, based on his recommendations I would use a cheap nodemcu to read the pulse before sending it to the pi for more calculations. Or better still, I might just use the nodemcu for everything.

Problemchild · Answer

Absolutely Doug, I see +/- 24 V on the sensor which is obviously enough to send the RPI cooking. Still not sure how the signal comes out of that sensor is it analog/pulses what voltages etc. In practice you'll need a separate signal conditioning and acquisition board then if you want to read this in to a Pi then do this via a standard Micro interface rather than direct to this beasty

netromaster · Answer

here's the schematic and picture image of the electric interface.