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Force Restoration Scale Principles
Modern force restoration scales, used in the analytical and laboratory scale markets, are quite similar in basic construction. They are based upon the use of a Roberval structure which allows them to be top loading and eliminates the effects of end loading and side loading. Roberval structures have been used in laboratory weighing for a long time. An illustration of an application can be seen on www.torbalscales.com/, where the first page of an early patent shows an equal arm top loading structure where taut bands are used in place of today’s flexures and individual weights are placed on a pan in place of the modern electromagnetic force motor. The use of a parallelogram with flexures allowed weight to be placed directly on a pan above the whole structure, where previously hanging pans on equal arms had been the norm.
I switched computers and my scale connection to the PC is not working.
We had a scale connect to a PC where everything worked. We now connected the scale to a new PC that just arrived and we can not get the connection right even though we are using the identical setting?
Crane Scales with ground floor controllers
Using a Crane Scale can be something of a pain if the controls and the display are an integral part of the scale that mounts on the crane hook. The problem occurs if the load being weighed requires that the hook be far overhead in order to lift the load clear of the deck. This makes reading the display difficult and can make operating any of the controls impossible. Most operators handle the problem with some sort of a work around, like a ladder or platform.
The Hierarchy of Accuracy, Resolution, and Capacity for Scales
Scales follow a fairly well defined hierarchy which is based upon their accuracy (linearity), and their resolution. For instance, an analytical scale usually presents a resolution of a part in one million (1:1,000,000) with a linearity of +/- 2 parts per million (+/-0.0002%). These scales set the accuracy standards for scales produced in commercial quantities. On the other hand, the laboratory scale is still a high accuracy device with resolutions of one part per one hundred thousand (1:100,000) and linearity of +/-2 parts per one hundred thousand (+/-0.002%). These are the work horses of our research laboratories, our quality control laboratories, our gemstone businesses, our higher education labs, and many other applications requiring their kind of performance.
Scale Calibration and why it is necessary in high accuracy scales
Calibration (which is usually re-calibration) is certainly necessary if high precision weighing is being done and the nature of the project is such that verification information is required. In truth, any time you want to be sure the scale (a tool) is functioning as well as it can, before you start to use it calibrate it.
The Anatomy of a Modern Crane Scale
The modern crane scale has as its heart a strain gauge, usually of high capacity. The strain gauge is very well suited to this application as it provides adequate resolution and accuracy for the application in almost unlimited capacities.
These scales can be thought of as strain gauges with their necessary electronics and display attached to them, all suspended between the crane hook and its replacement hook attached to the lower portion of the strain gauge. The hanging weight, then, is passed directly from the lower hook (on the lower portion of the strain gauge) to the strain gauge and then to the crane hook (via a shackle or equivalent attached to the upper portion of the strain gauge).
The Anatomy of a Modern Platform Scale
Platform scales are widely used in a great variety of industrial weighing situation. One very common application is weighing packages as they are readied for shipment. These scales get their name from the large flat weighing surface which they present for loading the objects to be weighed. In most cases the weighing platform sits on the floor and the display is separated from the platform by a vertical column that raises the display to a more comfortable height for the user.
Weighing Units and Weighing
There are a variety of different weighing units used in different parts of the world. The two most popular in the U.S. and Europe are the metric unit, the gram (which includes the kilogram, Kg, the gram, g, and the milligram, mg) and the Imperial system unit, the pound (which includes the pound, lb, and the ounce, oz). In the Imperial system there are 16 ounces to a pound.
Connecting multiple scales to a PC via USB, and using Procell or Torbal Communcations Software.
To run multiple scales with one computer via a USB port you must first determine the virtual comports that a computer selects for your USB connection. To do so all you have to do is use Device Manager to determine USB virtual ports. Every scale you connect you will have a different USB comport assigned. To collect data from multiple scales you must make sure that automatic reading function is turned off. This applies both to Procell and Communications. Automatic reading will cause the RS232 port connection to be continuously occupied; therefore it will not allow data passage from multiple units.
High Capacity Scales
There is an incredibly wide range of activities that require the use of balances. Scales for use in the trucking industry have to weigh tons. Pharmaceutical balances for activities like compounding, on the other hand, have to have .001g accuracy. In this article, we are going to take a look at scales with 1 g accuracy.
Parts counting
Thousands of years ago, the most elaborate tool known to man was a rock. Rocks were very easy to use, and they were just lying around all over the place.
Then someone got the bright idea to lash a sharpened rock to a stick for hunting. And thus the era of tools began. And the tools have done nothing but get more complex ever since! Modern machinery can contain dozens, hundreds or even thousands of parts.
Platform Balances
The world would be a very different place without the invention of the balance. The ability to accurately determine weight and mass has had an incalculable effect on the forward progress of mankind. One major subset of the balance family is the platform balance. Let’s take a moment and explore the world of platform balances.