Special Load Cell (VCM)

[MAC3382]

Hello, All:

Is anyone familiar with a scale that utlizes a loadcell/mechanism that is elctronicaly compensated/Magnetic Force Correcting?

The way is was described is that as the mass is applied to the measuring pan there is displacement, however; unlike a traditional loadcell the pan is returned to the original start positon.

I am infering that the mass displaces a coil in relation to a magnetic field in a VCM. The electronics sensing the indcued voltage, applies a voltage to "right" the system. This applied voltage is proprtional to the applied mass. I need this zero displacement method for airgap measurments with a magnet. Our current loadcells and scales have up to a 0.009" displacement relative to are target mass (gf.)

I have not had any luck with a scale manufacturer's current product line, but I have a Metler-Toledo Technical Datasheet from 1985 which describes what I have above.

I appreciate any help you may have to offer.

thanks,

Mac

 

[Compositepro]

What you describe is a basic basic measurement principle that is often referred to as "force balance". The balancing force can be a counterweight or the magnetic force of a voice coil or a pneumatic pressure. I know that some Sartorious analytical balances use the voice coil principle.

Force balance is a principle used to build a measurement system. Define how much movement is acceptable (zero is not an option) and the force range. You may find a pre-designed product or may need to make your own. A classic method of detecting extremely small deflection is to mount a mirror on a quartz filament and detect a light beam that reflects from it.

 

[MAC3382]

To finish the thread.....

I found a company called Scitech. All of their scales use a VCM type device to return the system to a "null" position. The stop to stop stroke is 0.002" and the resolution is in micro-inches. So, there may be some deflection, but 100 less that my gap tolernace. The scale is working perfectly. (I do not have any relation to the company listed above other than being a customer.)

Cheers,

mac