Process Engineering Division – Instrumentation and Automation Section – Daily Topics – Topic No. 2020-12-24
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Process Engineering Division – Instrumentation and Automation Section – Daily Topics – Topic No. 2020-12-24: Discussion topic: 336. The temperature measurement range of a certain temperature measuring instrument is 0–1000°C. According to the process requirements, the error in the temperature indication value must not exceed ±7°C; therefore, what precision grade should be selected? (5 points are given only to those who provide the correct answer; additional points are awarded for a correct calculation process or detailed explanation.)
7/1000 = 0.7%, so a precision grade of 0.5 should be selected.
A precision grade of 0.5 should be selected.
A precision grade of 0.5 should be selected
The temperature measurement range of a certain temperature measuring instrument is 0～1000℃. According to the process requirements, the error in the temperature indication value must not exceed ±7°C; therefore, what precision grade should be selected? Solution: According to the process requirements, the allowable error for the instrument = (±7/(1000–0)) × 100% = ±0.7%. Answer: A temperature measuring instrument with an accuracy class of 0.5 should be selected.
Accuracy = Maximum allowable error/Measurement range × 100% = 7/1000 × 100% = 0.7%. Since no accuracy level of 0.7 is available for this instrument, an accuracy level higher than 0.7 must be chosen; therefore, the selected accuracy level for this instrument is 0.5%.