Throughout most industrial environments, weight plays a critical role. Many commodities are purchased by weight; most mixing, blending, and formulating processes are weight dependent; shipping and receiving is weight related; sales as well are often based on weight increments even as small as 1/10 or even 1/1000 of a pound.
With time, digital platform scales now have onboard electronic intelligence, highly accurate load cells, LCD displays, and in the case of Arlyn Scales, networking capabilities. These features offer many advantages over mechanical scales and only one minor disadvantage.
The Cons of Digital Platform Scales
Only one disadvantage exists for the digital platform scale: it needs electricity to run. The load cells themselves require electricity, which makes truly “electric-free” operation impossible. Nevertheless, the rechargeable batteries solve this problem for Arlyn Scales.
When digital platform scales are used in production environments, uninterrupted power supplies (UPSs) may be available. This is common practice for data centers and hospitals where even a brief power outage is unacceptable.
The Pros of Digital Platform Scales
Digital platform scales are so much superior to mechanical platform scales that only two questions need to be answered when choosing between them: How accurate does the measurement need to be, and how much automation is desired? A need for high accuracy will be answered by a digital platform scale, as will a requirement for automated production. You can choose ultra precision with our internationally patented SAW technology, which is only available from Arlyn Scales, and you can set your sights on as much automation as current technology offers.
Two Kinds of Platform Scales: Mechanical and Digital Weighing Scales
Mechanical Weighing Scales
The most popular range of scale requirements is generally in the area of 500 lbs to 1000 lbs. and historically this was fulfilled by mechanical beam scales or dial scales. In both cases, a mechanical understructure included a set of pivots and bearings in each corner of the scale platform that transferred the load to a central steelyard rod. The rod ran through the center of the scale post and connected either to a sliding weight arm, or a spring dial. Typically, a scale of this type could resolve weight into increments of about .5 lb for a 1000 lb capacity.
There are a number of disadvantages to this type of analog balance weighing machine. First of all, there are a significant number of moving parts, including the pivots, bearings, hangers, linkages, lever arms and couplings. All of these parts wear during use and cause inaccuracies. They are also prone to friction errors caused by dirt collecting within the mechanism. Furthermore, the shock loading of the scale could cause deformations in the bearing surfaces.
Working with Mechanical Platform Scales
Also, mechanical scales are much more prone to user error. It is often difficult to read the weight from a sliding arm. And it is easy to make a mistake when viewing a dial scale. Mechanical platform scales have no onboard intelligence and relatively crude load measurement schemes. The measurement readout is often a dial or gauge with coarse increments, and even if the scale operator is very careful, the accuracy is not sufficient for most modern applications.
With a mechanical platform scale, the operator must be close to the scale to read the dial or gauge and errors in reading can easily occur. The operator then must write down the scale reading and perform math for subtracting tare weight, calculating parts count, and possibly converting weight units to volume units, for example, pounds to gallons. Another kind of conversion might be from pounds to kilograms and vice versa. The chance for human error is high and the work tedium adds to the problem.
Digital Weighing Scales
The digital platform scale eliminates the disadvantages of the mechanical platform scale but is dependent on a power source. In return, the digital platform scale allows applications that were not at all possible with the mechanical platform scale.
Working with Digital Platform Scales
Working with a digital platform scale greatly reduces or completely eliminates the chance for human error. The scale has a high degree of accuracy from the use of electronic load cells, and the scale readout can be displayed on a large LCD screen. Onboard intelligence can perform all required math functions, and the data from the scale can be fed into a computer or onto a storage device for storage and further analysis.
Control of the digital platform scale can be done locally through a color touchscreen or remotely through a computer connected to the scale. The operator does not necessarily have to be close to the scale. Digital platform scales have other significant advantages as well that will likely change the way you think of scales in production environments.
Which Digital Weighing Scale to Buy
The type of industrial scale that is used to determine weight is associated with the maximum amount that is being weighed on the scale at any one time. For very small amounts, a laboratory balance would be most suitable. Bench scales would be used for ranges up to about 100 lbs. Platform scales are appropriate up to 1000 lbs, and large floor scales can have capacities from 2,500 lbs to more than 30,000 lbs.
Arlyn Scales uses a superior approach design in their platform scales. Instead of a single large load cell, four advanced design shear beam load cells are used. One is placed in each corner of the scale. These load cells can be of much lower profile, as they do not have to resist side loads. For even better performance, the load cells are made out of stainless steel, instead of aluminum that is often used for bending beam load cells. This provides added overload and shock load capability.
The load cell outputs must be carefully matched so that the same correct reading will be obtained no matter where the load is placed on the platform. One method to accomplish this is to use a summation board, with trimmer resistors used to match the outputs. Another method is to pre-match the load cells for each scale, so they only need to be wired together. This avoids the additional parts and errors that can come from changes in the trimmer adjustment.
The support of networked digital platform scales brings in possibilities not otherwise available. Up to 10 scales can be connected using the RS-485 ports in a production field of up to 4,000 feet. Arlyn Scales supports set point and up to 8 solid-state relays per scale that can control other production equipment based on weight readings. This has proven valuable in many production environments, such as pharmaceuticals, mixing paint, and metallurgy.
Direct PC Connection
A simpler situation can be accomplished using the RS-232 port for connecting to a PC. This port is bi-directional, so the operator can control the scale while collecting data from it. Free software supplied by Arlyn Scales can take the data and put it into Excel spreadsheets or Access databases.
These scales also support wired or wireless Ethernet, which means your scales can be controlled from the Internet. This also means that scale measurements can be fed to any kind of computer, from a tablet on up to a scientific supercomputer. Since the network here is the worldwide web, the scales and computers can be located anywhere that Internet connections are available.
We know many of our clients use their platform scales in the field where no power is available, which is why we offer battery-driven scales with rechargeable battery packs. You can collect data from the scale via the USB port and a flash memory card, after which you can load the data into most modern computers via their USB ports.
Finally, if any of the regular options do not fit your exacting needs, you can ask Arlyn Scales to build custom scales that do. Read about a wide range of custom solutions we have found clients here.
The Advantages and Disadvantages On Balance
The choice between digital vs manual platform scales depends on how much accuracy you need and/or how much automation. Perhaps you have thought of ways that your production will benefit from the use of digital platform scales, or how much easier life will be with the high accuracy and the elimination of human error.
As a factory-direct business, we’re able to offer cost-effective solutions. Also, be sure to ask about scale finishes and materials; Arlyn Scales offers several options, including high corrosion resistance. If ultra-high accuracy is your requirement, ask about SAW, a new kind of load cell transducer technology only available from Arlyn Scales.
Digital platform scales may be just what your business needs to increase production, in which case you should contact Arlyn Scales to speak with one of our representatives about your individual needs.