Electronic measuring instruments are designed to provide very accurate results. For industrial applications, there are instruments for measuring temperature, pressure, voltage and current, color, light levels, sound frequency and amplitude, velocity, and a very wide variety of other values.
One of the most common applications is for electronic scales to accurately measure weight. There are a wide variety of different tasks requiring different types of digital scales. They include parts counting scales, cylinder scales, floor scales, platform scales, bench scales, and crane scales, among others. The environments in which these industrial scales will operate can also vary considerably. In some cases, there may be laboratory type conditions, where the temperature remains stable, and there are no conditions that could harm a sensitive instrument. A standard assembly location could be another typical application. In this case, there may be a wider variation of temperature, and the scales may be handled more roughly. For this reason, it would be suitable for the scale to be provided with a stainless steel version of the transducer, known as a load cell. But even in this case, the scale will not be required to withstand high levels of moisture or chemical exposure.
Within an average factory situation, there may be somewhat harsher conditions. The scales may be loaded and unloaded using automatic equipment. Again, it is important to use stainless steel load cells instead of aluminum units. This allows the digital scale to withstand shock load and overload situations. There is a greater likelihood that the electronic scale could be subjected to water and high moisture levels. The stainless steel load cells will be important in this case. In fact, it may be advisable for the entire industrial scale to be manufactured from stainless steel. This will prevent rust from damaging the scale over time.
While stainless steel construction will protect the scale from most industrial environments, there are still many situations that require even better protection. Throughout the chemical processing industry, there may be chemical exposure that can damage a standard industrial scale. These include situations where there may be strong acids or alkali materials. Even the fumes from these materials can be damaging. Other industries where these materials may be present are water treatment and waste water treatment. Cylinders of highly corrosive liquefied gasses, such as chlorine and sulfur dioxide are widespread. Drums of caustics, fluoride, sodium hypochlorite and others are often present.
Because of its general corrosion resistance, stainless steel should be used for the general construction of the scale. But this material requires additional protection.
A very effective method to offer this protection is to coat the stainless steel with a material that will bond well to the stainless material itself, and will offer excellent protection from the chemical exposure. Arlyn Scales uses a specially formulated epoxy coating for this purpose. This epoxy includes a polyamine base for its high level of corrosion protection. While the epoxy demonstrated excellent bonding to the stainless steel surface, it is likely to be scratched as drums are placed onto the scale platform. To avoid this problem, a garnet sand is added to the epoxy before application. The garnet particles are extremely hard, protecting the surface of the coating.
Of course, the digital scale must be protected from its environment. But is must still include all of the functions and features that are needed to perform its task of weight measurement. Accuracy is usually the most important parameter. High quality corrosion resistant scales, such as those offered by Arlyn Scales, will generally provide accuracy as high as one tenth of one percent. This should be throughout the entire range of capacity and platform size. The ability to weigh in different units, such as pounds, ounces, kilograms and grams is also important. The digital indicator must be easy to view and understand. A graphics Liquid Crystal Display is ideal for this purpose. Communication with other industrial equipment is also essential. While RS-232 has been the electronic protocol for many years, newer RS-485 and USB formats are now easier to use. Ethernet output has also become prevalent on the factory floor. This can allow the scale to be controlled, and its data to be collected, from anywhere within the Local Area Network. For more sophisticated applications, the scales can also be queried over the Internet, providing monitoring capabilities from virtually everywhere.