Load Measurement

1- it is not clear enough, better explain what you want to do in a more detailed way.

2- you use qualitative estimations (fast for instance) fast for one is not same fast for the other so that you should give the band pass frequency and the frequency of data sampling and acquisition since this is needed for the connected electronic module.

1 - I would like to measure the load in vertical direction. The fixture will be placed on top of the product and then the guage would be lifted and dropped. This would fall with gravity and measure the load. If I couple this with pneumatic cylinder then the load value is high as well as large variations creep in.

2- The load measurement should be complete within 4-5 seconds. Also I would like to use some standard system available and integrate it with the fixture. Using a NI system would mean that the system can not be made portable to some extent.

I was aking is there any such push pull guage which has a memory inbuilt in it of around 2GB (say some SD Card)?

What do you want to measure? As long as the pack hangs the gauge will be loaded with G+Gg2. When you cut the bond and the sytem is in free fall the gauge will be sensitive ONLY to the dynamics of Gg1 with respect to the G+Gg2 and this only due to the mass of Gg1 and the stiffness "C" of the gauge sensitive zone. Of course there are also some aerodynamic forces but will obtain in fact an oscillation only function of Gg1 and C. Provided -it is what I suppose - that G>>Gg1+Gg2.

Is it what you expect? It is not very probable that you will find a "gauge " as you want since what you want is a sensor with data acquisition and data processing and data saving. The band pass in which you will have to work has (as you explain the test) nothing to do with the free fall so that the 4..5 s are NOT defining the acquisition dynamics or the ADC you need. This can be defined only when you know the gauge stiffness.

Hope it will help. Let me know if you need a support to obtain the equations.

Hello,

Are you looking for Do-It-Yourself solution or off the shelf solution that you can purchase or custom built solution that you want to get developed.

If you are looking for Do-It-Yourself solution, please have look at solutions available from National Instruments (NI), like LabView

Regards

Madhav Chowdhary

Go to Futek.com they make them all and have a lot of usb stuff.

It is possible if a pressure transmitter output is connected to a datalogger / DAS.

Firstly for this you need to calculate the range of your force like at what pressure you get 1.5kg force / load.

Next note that your scale should be linear i.e, the load Vs Pressure scale if plotted across a graph should be a line not a parabolic / hyperbolic.

Hope you got near to answer

Thanks for the insight that all of you have provided.

When I had used the word free fall I meant a system that will offer the least amount of resistance while load measurement. Some probable combinations that have cropped up is: A small fixture with a push pull guage that can be dropped from a small distance to measure the load. But this guage would contain a strain guage.

Second would be a fixture with similar facility but having an impact sensor.

Third would be using stepper motor and a load cell. This wouldn't fulfill the earlier criteria of almost nil friction while operation.

Pneumatic system would be out of option as a small change in the pneumatic supply would change the force measurement as well as some change in the flow control valve.

But even using a fixture would actually give an offset value from the true answer. This would depend upon the mass of the bracket that is attached with the guage as well as the weight of the guage. I am presently working on the equations to establish such a concept.

If anyone has some insight/comment please share your views.

Make a sketch of what you want since with words it is always difficult to explain own ideas.