‌In order to meet regulatory requirements and achieve precision operation, the accuracy of the checkweigher must be tested. On the Internet, we can find many documents related to scale testing, although many of them are copied from each other and use many complex and obscure languages, and the calculations are also complicated. Because its description is difficult to understand, it even increases the misunderstanding of the test. In this article, we try to use the simplest language to explain how to use the checkweigher to accurately measure and determine the accuracy of the checkweigher.

For any weighing device, there are two errors that have a great impact on the accuracy of the device. One is repeatability, and the other is accuracy, that is, the correctness of the weighing result after comparison with a known weight (such as a weight). At the same time, in dynamic (online automatic) weighing and static (static) weighing, there are also two parameters that can be compared. In some documents, you may read other parameters such as environmental conditions, temperature, measurement uncertainty, product characteristics, tare weight, air buoyancy, etc. Forget all these parameters, we only test the products that need to be tested in the use environment.

Here are two small tests, which can help you use your dynamic checkweigher with confidence, but before introducing these two small tests, we will tell you two wrong practices.

Checkweigher commissioning

The biggest misunderstanding of online checkweigher testing is that it is done the same way as it is done to calibrate a static scale. Stop the conveyor and place the object on the weighing belt to see if it matches what you know. This is a safety hazard. When the conveyor belt is open, the checkweigher vibrates a lot and is in motion, which results in large errors that cannot be directly compared to the results when it is stationary. Therefore, the sensors of dynamic checkweighers must be specially designed to meet the accuracy requirements. In fact, the value obtained when the object is placed in the static state is only the starting reference point that engineers use to determine the dynamic weight. For example, when stationary, an automatic checkweigher weighs an object at 500g, while the same checkweigher weighs the same object at 502g when moving. At this point, the calibration scale needs to subtract 2g. Generally speaking, today's checkweighers have a value that can be compared and automatically adjusted by placing a static reference object.

Use a belt to read the value of an object with a known weight, such as a weight, to confirm that the scale is correct. Even if the weight of the weight is the same as your product, it will have a large error due to the dynamics when it is transported on the conveyor belt (for example, different lengths and shapes).

I hope the above content is helpful to you. Tomorrow we will continue to share two methods to correctly check whether your weighing scale is accurate. If there is a problem with the checkweigher, please contact us.