Rheometer

Hi,

I need to create a rheometer for material until 50Nm.

The idea is create something like this:

The idea is control this with LABVIEW.

I have checked some parts:

1 - torque meter -
https://www.datum-electronics.co.uk/media/js/upload/uploads/m425-rotary-torque-transducer-handbook.pdf

It's possible to read directly from USB with RS485 converter.

2 - Motor, encoder and gearbox:
DB87M01-S — BRUSHLESS DC MOTOR

1000 Cycles per Revolution

GPLE80-3S-512-F87— PRECISION PLANETARY GEARBOXES

Ok.

After that the idea is control all with 1 usb interface (conection between my system and computer) but I have no idea how to control this motor.. because native controler is to confuse.. and i need only one usb connection.

Any other Idea for the system ? Other motor ?

it's possible to use an arduino to control everything ?
RS485 torque meter/speed meter and servo motor via 485 ?

thanks

It's possible to control this motor: PD6-C – Stepper motor with integrated controller | NANOTEC with arduino ? Via RS485? Any other idea ?

Hi,
Defn Rheometer;

A rheometer is a laboratory device used to measure the way in which a liquid, suspension or slurry flows in response to applied forces. It is used for those fluids which cannot be defined by a single value of viscosity and therefore require more parameters to be set and measured than is the case for a viscometer. It measures the rheology of the fluid.
There are two distinctively different types of rheometers. Rheometers that control the applied shear stress or shear strain are called rotational or shear rheometers, whereas rheometers that apply extensional stress or extensional strain are extensional rheometers. Rotational or shear type rheometers are usually designed as either a native strain-controlled instrument (control and apply a user-defined shear strain which can then measure the resulting shear stress) or a native stress-controlled instrument (control and apply a user-defined shear stress and measure the resulting shear strain).

Just do we can see what you are trying to do.

What is your electronics, programming, Arduino, hardware experience?

Tom,.... :slight_smile:

OP's links posted correctly:

torque meter

Motor, encoder and gearbox

1000 Cycles per Revolution

PRECISION PLANETARY GEARBOXES

motor

The numbers just don’t work for me. What is the material than requires such an incredibly low speed and such high forces? 0.1 revs/second maximum speed and 50 Nm?

IIRC, many of the lower end meters just use a torque arm/spring mechanism. Simple physics wins every time for cost and reliability.

Which leads me to ask: why use a torque meter? Characterize the gearbox friction across the speed range and use motor current minus observed friction. Unless you’re looking for better than five percent or so accuracy, that torque meter is a really expensive addition, IMO.

"Characterise the gearbox friction" sounds like a good reason to buy a torque meter. Or just measure the torque directly as per the original proposal.

The fluid under test is obviously something odd, like asphalt or molasses. Hence the high torque.

I would not attempt to measure torque in the rotating shaft. You need all sorts of bearings and vertical space to isolate the torque meter from shaft bending. I would put the torque meter in the motor mounts to measure the reaction force. This kind of static torque meter is much cheaper and you can even do 6-axis sensing.

The RS585 data format looks easy enough to read with an Arduino and an RS485 shield.