Load Sensor Technology Behind Truck Weighbridge Scales

Whether for mining sites, high-volume farms, or free-ways, heavy-duty weighbridge truck scales are built to handle an enormous amount of weight. For instance, truck weighing stations are usually fitted with these scales to ensure that the weight of the truck (and its load) is captured for variety of reasons (i.e. tax purposes, daily business operations, and ensuring that the weight falls within the safety guidelines.)

This weight is usually calculated through two measurements; the axle weight which constitutes the amount of weight carried by each axle and the Gross weight which is the combined weight of all the axles. Truck scales are usually built out of a combination of concrete and steel.

It's All in the Load Cell

To accurately measure the weight of a truck, these truck weighbridge scales usually use load cells to capture the weight. A load cell is simply a transducer or sensor which converts a force or load into an electric signal. This signal can either be a frequency change, a current change or a voltage change; all this does depend on the circuitry and the type of load cell that’s been used.

These load cells can be made using inductive, resistive or capacitive techniques. The most common load cell technology for truck weighbridge scales tend to be resistive; working on the on the principle of change of resistance in response to an applied load. In other areas they are termed as piezoresistive, which is something that changes in response to an applied squeeze or pressure.

Truck Load Sensor Componentry

The load sensors on most truck weighbridge scales are built using resistive bonded strain gauges. A strain gauge basically consists of wires which transmit a very mild electric current. The strain gauges can either be tension or compression based. A tension strain gauge is based on the slight change in shape of the cell that’s caused by the weight while a compression strain gauge is based on how much the cell compresses when some pressure is applied on it.

Usually 4 strain gauges are configured in a Wheatstone bridge configuration with 4 separate resistors connected. An excitation voltage of 10V is usually applied to one set of corners and the difference in voltage between the two corners is measured between the other 2 corners; at equilibrium, with no applied load, the voltage output is usually zero or very close to zero.

When the metallic member to which these strain gauges are attached is stressed by any application of force, the strain experienced does lead to a change in resistance in either one or more of the resistors. This small change in resistance does result in a change in the output voltage. This change, however small can be measured and then digitized after accurate amplification of the rather small milli-voltage signals to a slightly higher amplitude of 0-10V or 0-5V.

Weighbridge Scale Software

These readings can then be captured by appropriate weighbridge software and utilized accordingly. It is worth mentioning that most of these truck weighbridge scale load sensors come fitted with high level digital output formats such Wi-Fi, Bluetooth, USB and Xbee Wireless capabilities.

Software-integrated truck weighbridge load sensors allow users of the system to monitor the output on a PC with the help of appropriate weighbridge software and generate the requisite reports and undertake a wide range of analysis. This also allows for the storage of this data for future use.

Portable Weighing Scale Technology for Heavy-Duty Trucks

From mining to agriculture, trucks need to be weighed in almost any industry that require load transport. Although fixed truck weighing scales are most vastly used for high volume applications (i.e. logistics and shipping operations), sometimes more versatile and simple truck scale systems offer greater functionality and efficiency.

Portable truck weighing scales are more and more popular because of the massive advantage they have over fixed scales: mobility. Portable truck weighing scales usually are designed using one of two common types of technology: Load Cell System and Bending Plate System.

Load Cell System 

Load cell is the most common and popular method used in portable scale’s functionality. Each cell is made of steel or such strong materials and they are accompanied by straining gauges that transmit electrical currents.

Whenever trucks pull over the cells, the amount of current that runs through the gauge changes and that change is interpreted by a junction. The difference between the primary and the changed currents determines the weight.

Bending Plate System

Although bending plate truck scale’s working principle is quite similar to the load cell scales’, they use plates instead of cells. When a truck pulls onto these plates, the straining gauges attached to them calculate the amount of stress being applied on each plate. This in turn determines the amount of weight needed to produce the determined stress.

There is another type of portable truck weighing scale system used in portable scales but it is highly uncommon. These scales are called piezoelectric scales and they use conductive material wired with sensors to weigh trucks.

Benefits of Portable Truck Weighing Scales

The benefits that AgWeigh's portable truck scales for sale have over fixed scales are clear but let us take a better look at them below:

• The most obvious and attractive benefit is their mobility. Today’s industries are all about moving fast. Failing to keep up with the speed is enough to ensure steep falls in profits. With these scales any truck can be weighed anywhere and at any time as they can be carried around and set-up at will.
• These scales are lightweight so they are easy to carry around. There is no need to attach an extra trailer to carry it around. The assembly process is also very simple and does not take more than a few minutes to make them usable.
• They can literally be used in any kind of surface. Especially designed to be used in rugged surfaces, they do not require completely flat and smooth places to function properly.
• Portable truck scales do not need any kind of special maintenance. Regular servicing is enough to ensure years of functionality.

These benefits together can make a company more efficient in terms of time and profit. Depending on the company’s management skills, this efficiency helps in capturing a loyal portion of the total market as well.

Portable truck weighing scales from companies like PayloadPros.com offer all the functions offered by a fixed scale while keeping the service mobile.