1.Attention should be paid to the nominal value of the power supply voltage, the ground wire of the hardness tester and the polarity of the power supply, and to the grounding. Because when the hardness tester and the signal source (such as a computer) are connected by different power sources, there may be a high potential difference between the two zero lines. When the user plugs signal wires or other plugs with electricity, there will be a fire phenomenon between the plugs and sockets, which will damage the signal input circuit, thus possibly causing damage to the hardness tester.
2.The hardness of the hardness tester should not be switched on and off frequently, because this may damage the internal equipment components of the hardness tester and reduce the service life of the lamp.
3. The refresh frequency of input source should not be too high. Although the higher the refresh frequency of the input signal source, the better the image quality, we must also consider the refresh frequency of the computer monitors connected to it when using hardness timing. If the two are not consistent, the signal will not be synchronized and can not be displayed. This is also why the screen that can be played normally on the computer can not be projected through the hardness tester.