US Solid Scale

Discussion in 'Gear Talk: What to Buy? and Gear Evaluations' started by flopearedmule, Nov 30, 2019.

  1. flopearedmule

    flopearedmule

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  2. ronemus

    ronemus Silver $$ Contributor

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    The Amazon listing is for a strain gauge balance with all the shortcomings of the breed, and that model doesn't read in grains (inconvenient but not a show stopper). Strain gauge balances drift enough that it's unlikely to really be useful to routinely measure with milligram resolution as advertised.

    The U. S. Solid site doesn't have any technical documents or detailed specifications available, so I can't evaluate it; however, it doesn't read in grains either. If it's a force restoration balance, the price undercuts the A&D FX-120i which has been the entry point for that technology. If it's another strain gauge balance the price is rather high for the routine performance you would get.
     
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  3. flopearedmule

    flopearedmule

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    You are right, it doesn't read in grains. I didn't see that. I guess that won't work.

    If it's a force restoration balance, the price undercuts the A&D FX-120i which has been the entry point for that technology. If it's another strain gauge balance the price is rather high for the routine performance you would get.

    Can you Please explain the difference between force restoration and another strain gauge balance?

    Edit: I found a video that explains it.....Thanks for pointing that out.
     
  4. ronemus

    ronemus Silver $$ Contributor

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    A strain gauge scale uses a mechanical sensor whose output changes as the load varies. It is difficult to linearize the response so that the output has a 1:1 relationship to the load, and the response changes with temperature. This technology is relatively inexpensive and works fairly well in many applications.

    A force restoration uses the current in a wire coil to return the balance to a reference position when a load is applied; many factors cancel out using this scheme, and they are inherently very linear. This technology dominates the market in multi-thousand dollar laboratory balances (I have routinely used lab balances that cost more than a new car), and the A&D FX-120i was the first "affordable" balance using it.

    Prior to ~1980 laboratory balances were literally balances, using a rocker arm with the sample to be measured on one end and a series of weights of known value on the other. They were mechanically complex and required a set of weights with very high accuracy; originally the weights were external to the balance and an operator had to choose the combination that matched the sample and calculate the sum - talk about cumbersome! Force restoration balances were much less expensive (no weights and shuttle system) and took over the market in a few years. The price will continue to drop, but probably not by a lot; I wouldn't expect to see them for less than ~$500 except as closeout/special sales. You can appreciate the revolution if you price a set of high-precision reference weights and think of the advantages of removing them from the manufactring cost of balances.
     
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  5. Falfan2017

    Falfan2017

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