USB Flash Drive Stores Industrial Scale Data

The need to know weight information is pervasive throughout virtually every industrial application. Every company has items they need to ship. They may employ a simple bench scale to determine the weight of packages that are being sent by mail, or by some other parcel service. For heavier items, platform scales are used to weigh boxes, bags and other packages up to about 1000 lb. These may be shipped by parcel services or by truck. Pallets or totes of materials are weighed on large floor scales, and are usually shipped by common carrier. This weight information is often used directly by the operator of the electronic scale. The package that is weighed on the bench scale must have the correct postage applied to it. The shipping clerk will record the weight on the display of the platform scale and will insert the value into a trucking bill of lading. Forklift operators can place pallets directly onto the industrial scale and use the weight values to enter into a manifest of the shipping carrier. Electronic scales have been designed to be very accurate. In industrial situations, many digital scales that are chosen usually have accuracies in the range of 1/10 of 1%. These industrial scales typically are fabricated using a technology known as strain gage load cells. They incorporate a machined piece of metal that acts as an almost perfect spring. Depending on the load on the scale platform, this spring will deform by a certain, very repeatable amount. When the load is removed, the spring returns to its original position. Very thin, deformable resistors, known as strain gages, are bonded to the surface of this spring element. As the spring bends, the resistor is slightly stretched, and the value of resistance will change by a very small amount. Sensitive electronics detect these changes of resistance, amplify them into a larger analog signal, and convert this analog signal into a digital value. A microcomputer processes this value and presents it in a manner that is analogous to the weight on the scale. Control buttons on the electronic scale allow the operator to view the data in the desired format, including weight units such as pounds or kilograms or ounces. Some applications require even more precise weight determination. This can be the case in formulating chemicals, inks or dyes, pharmaceuticals, and a variety of other demanding situations. Other industrial scale technologies, such as Arlyn Scales Ultra Precision Surface Acoustic Wave (SAW) units may be used to provide an accuracy level of 1/100 of 1% or even better. Once again, an internal microcomputer must take the data provided by the scale transducer and process it into a mode that will be appropriate for the user. While the scales may be extremely precise, humans may be much less so. The task of taking the data from the display of an industrial scale and writing that weight into the proper document, or copying it into a computer database can introduce operator error. The most obvious way to avoid this problem is to connect the electronic scale directly to a computer, using some sort of data communication protocol. Many digital scales do offer that option, utilizing the industry standard RS-232 serial communication standard, or alternatively, an Ethernet standard. The computer can simply collect the weight data, or it can use its own printer to provide labels or other types of hard copy. While this is an effective method, it requires that a computer be available in the same general vicinity of the scale. In applications where there are a large number of scales, there may need to be a number of computers, or many communication cables. In fact, it may be quite impractical to provide the computer, especially if the environment is not computer friendly. In many cases, a much more practical and cost effective method would be to collect the weight data in a USB memory stick, or flash drive. These devices have become ubiquitous throughout the world. They are used to store backup data from computers, or music for mp3 devices, or many other applications. They have become very inexpensive. Some industrial scales now offer a special USB port which will accept this flash drive. A USB flash drive with a capacity of 1 GB currently has a cost in the range of $5. In can store hundreds of thousands of weight readings. After being used in a scale, these memory sticks can be brought to any computer within the facility, and downloaded into a database or spreadsheet. There will be no possibility of human error, so the weight data can be provided at the full accuracy level of the industrial scale.