1. Improvement methods:
Load CellThe improvement method for temperature characteristics is to perform zero temperature coefficient compensation and sensitivity temperature compensation. The current compensation process is quite mature and can reach below 20ppm/℃. As for the specific compensation method, as it is related to the specific detection circuit, we will not elaborate further here.
2. Difficulty in implementing improvement methods:
When we want to improve the zero temperature characteristic of the sensor, we first need to measure it, and then we can use compensation methods to improve it. During the production process of sensors, especially in mass production, the discreteness of the zero temperature characteristics of sensors is still significant, so it is not possible to compensate each sensor with a unified compensation parameter. Only one sensor is tested and compensated separately; After compensation, individual retests are required to verify the effectiveness of the compensation. It can be imagined that when producing weighing sensors in large quantities, the testing workload is very large and it is also very difficult to complete; Moreover, this type of test needs to be completed under different environmental conditions (-10 ℃~40 ℃), and the difficulty level can be imagined.
To complete this task, the first step is to prepare a large environmental laboratory where the internal temperature can be adjusted arbitrarily between -10 ℃ and 40 ℃, with minimal temperature differences at different locations in the greenhouse, and the accuracy of temperature control should be quite high. So, the cost of this type of greenhouse is very expensive.
Secondly, since there may be several hundred units loaded at a time in a greenhouse, data collection cannot be done manually (which is prone to errors). So, generally, data collection systems and database technology should be equipped, and computer management should be used, which is also expensive.
When the output of sensors is high, multiple sets of greenhouse and data collection systems are required, which requires a large amount of investment. This kind of capital investment is very large for a small enterprise and difficult to afford.
Let's talk about the difficulties in implementing sensitivity temperature compensation.
Firstly, it is necessary to have a high and low temperature test chamber, which should also have a working temperature range of -10 ℃ to 40 ℃. The temperature uniformity and accuracy inside the chamber are highly required.
Secondly, this temperature box must be installed together with the force machine, even if the sensor is in the temperature box, it must also withstand external forces when subjected to environmental temperature changes. And this type of force machine must be a high-precision force machine, usually using a static weight type. Some lever machines are barely available, while comparative force machines are generally not suitable. The manufacturing requirements for static gravity machines are high and the price is very expensive. For example, a static gravity machine with weights made of stainless steel is estimated to cost millions of yuan.
It can be seen that this kind of capital investment is not something that a small enterprise can afford.
The two main temperature characteristics of the weighing sensor, the zero temperature coefficient (the influence of temperature on the minimum static load output) and the sensitivity temperature coefficient (the influence of temperature on sensitivity), have a direct impact on the performance of the scale. In order to produce high-precision scales, it is necessary to effectively compensate them. During the compensation process, a large amount of testing is required, and the capital investment in these testing equipment is huge. Only large enterprises with advanced sensor manufacturing technology and strong strength can do this work well.
Guangzhou Zhongxin Automation Technology Co., LtdBased on years of experience and technical accumulation in the industry, the selection and application cases of weighing sensors have been recognized by a large number of customers. New and old customers are welcome to call for consultation:
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Sales Engineer - Miss Chen