Any type of scale must be able to show the amount of weight on the platform. It must also be able to be controlled by the scale user. A wide variety of different types of display technologies are used. Traditionally a red LED numeric display would show the weight value. Some disadvantages of LED’s are that they consume quite a bit of power. While they are excellent for low light areas, bright light or sunlight can easily obscure the display. While it is possible to produce an alphanumeric LED display, they are often limited to simple digits, along with a number of indicator lights. This significantly reduces the amount of information that is passed along to the user. It can also be more difficult to understand the meanings of the individual indicator lights.
Another display type that has seen significant usage is electroluminescent versions. These are often green or blue green in color. Initially, the major advantage over LED’s could be reduced power consumption. But they often need high voltages to be generated within the scale to operate. Care has to be exercised to make sure that these high voltages do not interfere with the very sensitive and accurate weight measuring circuits within the scale.
By far, the most common display with more modern industrial scales has been the Liquid Crystal Display, or LCD. Most often, this is a black display on a silver background, although other colors are also available. Some of the major advantages include a much lower level of power consumption. This can be very useful when the scales are used from battery power. Also, the display can often be considerably larger than other types. This is important in an industrial environment, where the scale may be at a distance from the user. Instead of simple indicator lights, various legends may be built into the LCD display, such as “pounds” or “grams” or “ounces” as the unit of measure. This will reduce user confusion considerably.
While most LCD scales still retain a fairly simple numeric display, some higher quality units use a graphics type of LCD. For example, all of Arlyn Scales industrial units incorporate a large dot matrix graphics system. This enables a sophisticated “Graphics User Interface”, or GUI, which will allow very clear concise scale operation, but with a large number of desired features. When the scale is simply showing the weight, the numerals on the display can be very large, block digits. This allows the weight to be seen by a scale operator who may need to be standing some distance away from the scale.
But a graphics display may also be put into a “menu” mode that prompts the user through a specific operation. For example, scales need to be calibrated to obtain their best accuracy levels. Choosing “Calibration” on the menu moves the screen into a series of messages. First, the user will be told to remove everything from the scale platform. Next, the screen will prompt the user to enter the value of the standard weight that they are using to calibrate the scale. Then, the user will zero the scale, and place the weight in the center of the platform. Again, the display will prompt the user to push a button when the weight is placed on the platform. After the scale completes its automatic calibration routine, it will display a message notifying the user that the process is finished.
Another useful feature of the graphics display is that it may display a number of different values at the same time. If the scale is in a parts counting mode, instead of one large weight display, the scale can show the number of pieces on the scale platform, the weight on the platform, and the piece weight of the item being counted. Of course, these digits will be smaller than the large weight display, but it is often a useful method of showing all of the requested data.