In an age where constant email checking is becoming a necessity, Wi-Fi is all the rage. Besides being important in the home and the office, it is found in airports, at train stations, and on moving buses. Now, it is also found in industrial scales.

A few higher-quality electronic scale manufacturers, such as Arlyn Scales, are now providing wi-fi connectivity as an option in much of their industrial scale lines. Previous to wireless, there were several methods for linking digital platform scales, bench scales, and floor scales to computers. RS-232 allows one scale to be linked to a computer. RS-485 allows several electronic scales at a time to be linked to a computer. For both of these protocols, RS-232 and RS-485 to USB converters are available. In these cases, the computer linkage can be used to store precise digital weight information in databases and spreadsheets.

More recently, Ethernet connectivity has become a common protocol for connecting digital scales into a Local Area Network. Besides allowing an industrial scale to be controlled and monitored from any computer on the network, this method also allows access to a scale controller from anywhere in the world, over the internet. Arlyn Scales even provides Remote Indicator software with its network electronic scales, which can read scale information on any computer with internet access.

RS-232, RS-485, and Ethernet all pose one typical difficulty-they require cabling. Often, an industrial scale may be found on a factory work floor that is several hundred feet away from a monitoring room or office. Particularly with RS-232 and RS-485, cabling becomes very expensive. Ethernet is much more commonly found built into many modern buildings for the purpose of having a Local Access Network, so very often, a building does not have to be retrofitted. Wireless connectivity, however, has the same benefits as Ethernet, when built into industrial scales, without requiring the cabling. Electronic scales can still be accessed from any computer on the network as well as from any computer in the world using the Remote Indicator software.

It seems quite obvious that it is necessary to accurately measure all of the ingredients that must be mixed together to manufacture any formulation. What is not as obvious is the level of accuracy that must be attained. This, of course, is highly dependent on the material being formulated. Some types of mixtures are, by their nature, not very accurate and standard. This may be the case with agricultural products and animal feed mixtures. Others may need higher accuracy, but these levels may be easily achieved by a regular digital scale. Standard industrial scales can provide accuracy as good as 1/10 of 1%. Many chemicals, cleaning solutions, foods, and other mixtures easily fall within this range. This allows the typical bench scales to be used for smaller quantities, or floor scales, platform scales or drum scales to be used for larger batches.

But this level of accuracy is not suitable for certain special formulations. Pharmaceuticals may need greater accuracy. Another field which typically requires extremely high precision weighing is the formulation of paints. While there are no safety issues here, the mixture of pigments and other ingredients must be exceedingly precise in order to satisfy the color sensitivity of the human eye. Even very small discrepancies between two batches of paint can be instantly identified when they are displayed side by side. This type of specialty weighing calls for ultra precision scales with accuracy ranges that are ten to twenty times better than regular industrial scales.

Arlyn Scales offers a range of ultra high precision digital scales known as SAW scales, or Surface Acoustic Wave scales. There is a range of bench scales with capacities ranging from 10 lb up to 100 lb. A second range of high capacity SAW scales range in capacity from 200 lb up to 500 lb. These may be used as bench scales, or alternatively as platform scales or drum scales. Paint mixing becomes a much more accurate process with this type of weighing instrument.

All types of liquids, powders, pellets, slurries and other materials are handled in a wide variety of different types of cans, buckets, pails, drums, tanks and other types of containers. Traditionally, these have been filled by hand. Liquids are often dispensed by a manually operated pump or gravity fed valve. Other types of materials may also be gravity fed, or filled by use of a conveyor or other type of device. In all of these cases, the accuracy of filling is dependent on the operator. Of course, it is also labor intensive, as the operator is needed at all times to monitor the filling process.

Industrial scales are perfect for monitoring the filling process. A bench scale is used to keep track of the weight during the filling process for smaller sized cans, pails and other containers. A drum scale will serve this purpose for drums and small tanks, whereas a platform scale or floor scale can handle larger dewars and larger tanks. While this will solve the accuracy issue, it still requires the filling operator to read the scale and control the filling process.

Arlyn Scales offers a programmable set-point controller for their entire line of bench scales, drum scales, platform scales and floor scales. This allows the filling operator to program the desired weight into the industrial scale. Electrical signals from the scale will control the filling device, shutting it off when the target weight is reached. While this minimizes the efforts required of the fill operator, there may still be some inaccuracies caused by latent delay in turning off pumps, and valves, and the material remaining in fill pipes or tubes.  This controller permits a second target value to be programmed, which can set the filling into a much slower trickle feed. Generally, this will be sufficient to obtain the desired target weights.

An industrial scale is a wonderful instrument for determining the weight of an item. Bench scales accurately weigh small items. Depending on the capacity of the digital scale, the readability of the weight can be as small as 0.0001 lb. Platform scales weigh larger packages and drums up to 1000 lb, whereas floor scales and pallet scales can accepts loads up to 20,000 lb. The accuracy of the electronic scale is dependent on the type of technology used. High quality industrial strain gage scales have an accuracy range of approximately 1/10 of 1%. If greater accuracy is required, alternate ultra precision scales, such as Arlyn Scales Surface Acoustic Wave technology can provide ten or even twenty times better accuracy.

But even an industrial scale with the best accuracy obtainable will not be of value within an industrial process if the user chooses not to use it because it is too difficult. Even if the electronic scale is being used, if the reading cannot be easily read, it is likely that inaccurate results will be obtained. Gross errors will occur if the front panel controls are confusing, potentially resulting in readings of kilograms where pounds are expected.

Good design practices can combine ease of use with excellent accuracy. For example, Arlyn Scales provides a combination of clearly marked front panel controls with a graphics, menu driven digital display. The user is guided through weighing operations by menu prompts which automatically scroll to the next operation. Furthermore, the very low profile of the industrial scales assist the scale operator in placing objects onto and off of the industrial scale platform. High quality stainless steel load cells protect the scale from damage caused by dropping items onto the scale platform, in addition to providing many years of trouble free use.

One of the most common types of industrial scales is the bench scale. Generally, they are available in capacities ranging from about 10 pounds up to approximately 150 lbs. As a rule of thumb, the lighter the capacity of the scale, the higher the resolution of the display. For example, a ten pound capacity scale may be able to display increments as small as 0.001 lb. Whereas a one hundred pound scale has ten times the capacity, it may have only one tenth of the readability, resulting in display increments of 0.01 lb.

Although the readability of the bench scale is important, the overall accuracy is a defining value. Arlyn Scales produces bench scales that provide levels of accuracy that are suitable for industrial measurement. Many of the important design elements that result in good accuracy can be traced to the electronic sensors of the digital scale. These sensors must be very rugged, or they will be quickly damaged in an industrial environment. But they must also be very sensitive. Additional characteristics include the ability to produce correct results over a wide range of temperature. For these reasons, Arlyn Scales uses a special stainless steel alloy in the production of their weight sensors. Additional electronics are built into the sensor to detect the ambient temperature of the bench scale, and to adjust the electronic output of the sensor to compensate for temperature variations.

Of course, the bench scale must also include accurate digitizing circuitry to convert the sensor output into a digital value for the display. These circuits must react quickly to any change in weight on the scale platform, while also filtering out the results of air movement and vibration.