Need some more assistance

[Ian Rogers]

I have a friend. He makes load cells. The latest escapade was for a 5mA output at zero with 4mA swing 4mA negative and 4mA positive.

All done and dusted. However.! The device being reproduced, doesn't work as it should. The original consumed 30mA where as the new one consumes 15ish mA. We have been told that the originals had hardware dampening. Well! I can't see dampening on the output working so I'm assuming the bridge or amp is being dampened.

Hence the ask! Can the output be dampened? How would it normally be done?

 

[schmitt trigger]

My understanding of dampening is that it affects the transient response, but should not affect the steady state response.

 

[schmitt trigger]

Unless the original circuit was prone to overshoot, and it was “fixed” by lowering the gain instead of fixing the poles and zeros.

Anyway, those are my two Yen.

 

[Tony Stewart]

It's hard to imagine if the circuit uses a buffered voltage source with low impedance and thus high damping factor or a current source. But low impedance often consumes more quiescent current to get the drivers into a lower impedance state. So reducing the idle current in the drivers raises output impedance thus damping factor. But that only applies to woofer with back EMF which is damped by the driver and not a resistive load cell. So not sure what they meant. But it is a problem?

 

[rjenkinsgb]

We have been told that the originals had hardware dampening.

"Hardware damping" implies a physical damper within the unit - a hydraulic or viscous fluid type. Those are quite common.
That would be to prevent bouncing or ringing of the mechanics when a load is suddenly applied or removed.

An undamped one could take a lot longer to settle to a steady reading, depending on the other mechanics.

 

[Ian Rogers]

All I can say, is the output appears to be sluggish.. When you apply load and when you remove load... I achieve the same with oversampling.. But I'm not in control of the software... I suppose the amp output before the voltage to milliamp has a filter circuit, I was just ponderring if it could be slugged after the convertor, I was just testing the water "so to speak"