Archive for year: 2007
The common procedure is as follows:
Below is an example of how to connect an indicator and a load cell.
Suppose we prepared a load cell whose capacity is larger than 3.6kg to measure 3kg. We would like to display the results using an indicator, but what kind of indicator should we use? The specifications of the load cell and the indicator are as follows:
Let’s presume that the load cell will output approx. 12mV when 3kg is loaded,
Suppose the indicator displays the weight in units of 0.1g between 0 and 3kg. This 0.1g is called the minimum scale division. As 3kg is divided by 30000 divisions (0.1g), the resolution is said to be 1/30000. Per 0.1g, the output will be:
The input sensitivity of the indicator is 0.33μV.As this value is smaller than 0.4μV, we can use this indicator. If the input sensitivity is larger than 0.4μV, the indicator cannot display the weight in units of 0.1g.
A load cell is a transducer that receives force in the form of a load and converts it into electronic signals. Devices such as indicators, computers or other measuring devices are necessary to display and use the electrical signals. The outputted values can then be saved in a database or printed and organized in various ways.
The following is an explanation of how to connect a load cell to an indicator:
The output cables of a load cell consist of two power cables (+/-), two signal cables (+/-), and one sield cable. There are five cables in total.
To reduce the risk of error, seven cables are sometimes used, with two additional sensing cables.
The instruction manuals of both load cells and indicators describe the kind and the color of each cable, so you can simply match and connect two cables of the same kind and color.
Once the cables are connected, it is necessary to conduct the calibration and set the various option settings. The required settings differ with different products, so it is highly recommended that you read the instruction manual.
Load cells are generally made from metals such as aluminum, iron and stainless-steel.
Listed among the load cell specifications, you can find the “fatigue life” of the load cell. The fatigue life indicates the number of times a rated capacity can be loaded.
For instance, if the fatigue life is 100,000 times, the weighted capacity can be loaded 100,000 times. When loading occurs more than 100,000 times, the load cell may not perform as well as guaranteed by its specifications.
Sudden shock or applying force that exceeds the rated capacity for a long time will damage the load cell. However, with proper usage, maintenance, and protection, the load cell can be used for many years, if not decades
Load Cells are classified into the following shapes:
It is important to use the load cell with the capacity and structure appropriate to the position where it will be used.
Single point load cells are often used for ordinary (small to medium sized) scales. The load point of the single point load cell is placed under the center of the weighing pan.
For industrial scales such as tanks and hoppers, beam and column load cells are normally used. One or multiple load cells may be necessary, but when using multiple load cells, the load applied onto each load cell should be even.
“S” load cells are typically used for tension measurements.
In various industries, it is becoming increasingly necessary to measure and computerize the weight (mass) of products in order to improve quality and productivity, and to reduce costs. The computerized data is often used for inspections and aggregate calculations.
Inside instruments (systems) that measure mass, load cells function as sensors that convert physical force into electrical signals. These electronic signals are then manipulated and finally the results are displayed on monitors for computers or other devices, or printed and saved.
Load cells are used for quick and precise measurements. Compared with other sensors, load cells are relatively more affordable and have a longer life span.
Load cells are sensors that detect force (mass, torque, etc.).
When force is applied to a load cell, it converts the force into an electrical signal. Load cells are also known as “load transducers,” because they convert a load (force) into electrical signals.
In the dictionary, a load cell is defined as a “weight measurement device necessary for electronic scales that display weights in digits.”
The sensors that measure force include sensors that utilize springs or piezofilms, pressure elements, displacement sensors, as well as a variety of other sensors. There are also a number of different load cells. These include magnetostrictive load cells, capacitance load cells, gyro load cells, and strain-gauge load cells.