Theoretical Basis of DS1820 High-Precision Temperature Measurement

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Theoretical Basis of DS1820 High-Precision Temperature Measurement [Copy link]

　　The temperature measurement resolution of DS1820 in normal use is 0.5℃, which is slightly insufficient for the temperature monitoring of the bearing of the hydro-turbine generator set. Based on the detailed analysis of the temperature measurement principle of DS1820, we adopt the method of directly reading the internal temporary register of DS1820 to increase the temperature measurement resolution of DS1820 to 0.1℃～0.01℃. 　　The distribution of the internal temporary register of DS1820 is shown in Table 1, where the 7th byte stores the count remaining value of counter 1 when the temperature register stops increasing, and the 8th byte stores the count value corresponding to each degree. In this way, we can obtain high-resolution temperature measurement results through the following method. First, use the read temporary register instruction (BEH) provided by DS1820 to read the temperature measurement result with a resolution of 0.5℃, then cut off the least significant bit (LSB) in the measurement result to obtain the integer part of the measured actual temperature Tinteger, and then use the BEH instruction to read the count residual value Mremainder and the count value per degree Mperdegree of counter 1. Taking into account the relationship that the integer part of the temperature measured by DS1820 has 0.25℃ and 0.75℃ as the carry limits, the actual temperature Tactual can be calculated using the following formula: 　　Tactual=(Tinteger-0.25℃)+(Mperdegree-Mremainder)/Mperdegree