Thermal resistance accuracy class
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For PT100 thermistors, a precision class of 1 is required – what does that mean? I thought they were classified as A or B. When selecting a temperature transmitter, I noticed that there is also a concept of precision; it can be set to 0.08% of the preset value plus a certain percentage of the measurement range, but it must be at least 0.2K. It can also be set to 0.1K. I’m a bit confused. This post was last edited by pwb1234 on 2009-3-13 at 14:33
Pt100 accuracy class: Class A: ±(0.15+0.002|t|); Class B: ±(0.30+0.005|t|). Note: |t| is the absolute value of the measured temperature.
Level 1 corresponds to 1%, just as with the way pressure is expressed. The main point in that earlier section is that the precision is 0.08% of the current range, but it cannot be less than 0.2K; in other words, if the value calculated based on 0.08% is less than 0.2K, then 0.2K will be used instead. This precision level of 0.2K can also be set to 0.1K during selection, but that would likely require an additional cost.
What is 1% relative to? Full scale? If Grade 1 is required, does choosing a Grade A instrument guarantee that the requirements will be met?
One is the accuracy class of the measuring element. For Pt100, the accuracy classes are: Class A: ±(0.15+0.002|t|); Class B: ±(0.30+0.005|t|). Note: |t| represents the absolute value of the measured temperature. Based on this calculation, does it meet the requirements for level 1? As for the error of the temperature transmitter, after checking, it can be as low as ±0.2%
Let me summarize it myself. Pt100 accuracy class: Class A: ±(0.15+0.002|t|); Class B: ±(0.30+0.005|t|). Note: |t| is the absolute value of the measured temperature. The first grade mentioned above requires that the ratio of the actual error to the full scale be less than 1%. It is possible to determine whether this precision level of 1% can be achieved through calculations (and a rough estimate shows that it’s generally possible to achieve it). In addition to PT100, transmitters also have an error; their precision is 0.08% of the current full scale, but it cannot be less than 0.2K. In other words, if the value calculated based on 0.08% is less than 0.2K, then 0.2K will be used instead. Moreover, when selecting such transmitters, the precision level of 0.2K can also be adjusted to 0.1K
Reply to 6# pwb1234 |t|: It represents the absolute value of the measured temperature. Is it an actual measured value or a theoretical value? For a range of 0 to 80, 50% corresponds to 40; if the actual measured value is 39.3, what should t be? ? ? What do 0.1K and 0.2K mean? ? ? ? By the way, my PT100 is of grade B, and the measurement error is 0.7 as mentioned above. Does this meet the accuracy requirement? ? ? ? ? Thank you so much.
What are the selection principles for Grade A and Grade B?