WEIGHING SYSTEMS AND SCALES

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The scale industry has traditionally offered two major technologies, Strain Gage and Force Restoration (also known as Force Motor). Arlyn Scales, based in East Rockaway, New York, has developed and introduced to the market a superior, third technology called Surface Acoustic Wave, or SAW (Surface Acoustic Wave) scales.

Strain Gage scales are the most widespread. They are also the least expensive. Typically, the resolution is 1:5,000 (1 part in 5,000). So a scale with a capacity of 50 kg will have a resolution of 0.01 kg. Likewise, a scale with a capacity of 100 kg will have a resolution of 0.kg lb. Premium scales will stretch this to 1:10,000. Recently, with the advent of modern electronics and compensation schemes, some vendors have offered much higher resolution. But actual accuracies have remained fairly similar, so very little is gained.

Force Restoration scales use the principal of an electromagnet force opposing the weight on the scale platform. This has the advantage of very high resolution and accuracy ranging from 1:50,000 to 1:150,000 or even higher. It has disadvantages that include some temperature instability and drift, and difficulty in implementing in scales with capacities of 25 kg and greater. It can also be prone to damage from overload and shock loading. Perhaps the greatest disadvantage is the cost, which can range from four times to more than ten times the cost of Strain Gage scales.

Arlyn’s new internationally patented SAW scales (Surface Acoustic Wave) incorporate similar technology to that used in fabricating semiconductor integrated circuits to produce an extremely precise digital output. Aluminized circuit patterns are deposited on lithium niobate substrates. Delay line circuitry develops a waveform with a frequency that is precisely associated with the weight on the scale platform.

These scales are available as lower capacity Bench Scales and as Platform Scales in capacities as high as 500 kg. These models are twenty times more accurate than Strain Gage scales, but less than 1/3 the cost of equivalent Force Restoration Scales. Whereas a high quality 50 kg capacity Strain Gage scale may have a resolution of 10 grams, Arlyn’s model SAW-C has a capacity of 50 kg and an amazing resolution of 0.5 gram!

Similarly, a 500 kg industrial Strain Gage scale may have resolution of 0.1 kg. Arlyn’s model SAW-MXL 500 kg industrial scale has resolution of 0.005 kg.

The large load cell block is extraordinarily rigid, providing unequaled levels of overload and shock tolerance. These scales may be used in harsh industrial environments.

Arlyn’s SAW scales are used in a wide variety of industrial applications that require higher accuracy that Strain Gage scales. Some of these include pharmaceuticals and biopharmaceuticals, paints and adhesives, electronics, chemicals, and food processing. They are also ideal for parts counting by weight, where the sample piece weight must be determined to a high degree of accuracy.

Along with the inherent very high level of precision, optional communication alternatives include USB, Ethernet, RS-485, Wi-Fi and others. These allow a high level of integration with other in-house systems. Further options include datalogging, setpoint target weight control of valves, pumps and other devices, and an advanced color touchscreen user interface.

www.arlynscales.com

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