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dakota digital speedometer calibration
Vehicle speed display mode
The Dakota digital automobile instrument is an independent analog meter, which is used to display the necessary information (such as vehicle speed, speed, water temperature, etc.). Later, it is developed into a combination instrument, which integrates all the meters together. With the development of science and technology, LCD is applied to the instrument, enriching the vehicle information displayed by the instrument.
From the initial segment code screen to dot matrix screen and monochrome TFT screen, digital display of vehicle speed can be designed at this time. Nowadays, color TFT is used in the instrument, the screen size is larger and larger, and the color is richer and richer. The analog meter designed to display on LCD also has a sense of science and technology.Pointer table: refer to the pointer on the left in the figure below.The analog meter can display the vehicle speed by controlling the deflection angle of the pointer. The design shall ensure the smooth movement of the pointer without jitter or large jump.
The analog meter of the mechanical mechanism is driven by a stepping motor to point to the number printed on the meter board.The analog meter in LCD is controlled by software logic to rotate the pointer on the screen and point to the number on the arc edge.Digital display: refer to the number displayed on the LCD in the middle of the figure below (000 km / h) Digital meter looks more convenient than analog meter. However, the consistency of numerical changes should be considered in the design.
How to calibrate speedometer
1. The actual speed is slow and the code meter is fast. I measured it with high-speed monitoring radar. The actual measured speed of my code meter 100 is only about 94. As far as I know, most cars are not too accurate;
2. Lead to the cause, such as tire (old and new wear, size), factory calibration (allowable error at factory), etc;
3. The diagnostic instrument can only detect whether it works normally. Some problems cannot be diagnosed. Find out about your car. Just know the difference. It's hard to deal with. It can only reduce the difference. It's meaningless.
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