Instruments: [Weekly Question] Week 44 of 2011: The issue of hysteresis in calibrating instruments
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This post was last edited by narshi on 2012-11-24 at 17:44. Topic: When checking the hysteresis of a meter, some people fix the input value and read the two corresponding output values for the upward and downward movements, while others fix the output value and read the two corresponding input values for those same movements. Which method is correct? Answer: According to the definition of hysteresis, it is the maximum difference between the two corresponding output values for the same input when the input value changes, expressed as a percentage of the output value; therefore, the first method is the correct one
When checking the hysteresis of a measuring instrument, the input value should be kept constant, and the two corresponding output values for the upward and downward movements are read; the maximum difference between these values for the same input signal represents the hysteresis
Hysteresis refers to the maximum difference between two corresponding output values for the same input when the input value increases and decreases; therefore, the first method is correct
The input value remains fixed; read the two corresponding output values for the upward and downward strokes
Keep the input value constant, and read the two corresponding output values for the upward and downward strokes
Reply to 1# Baghdad: According to the definition of hysteresis, it is the maximum difference between two corresponding output values for the same input when the input value increases or decreases, and it is expressed as a percentage of the output value; therefore, the former method is correct
Hysteresis refers to the maximum deviation between the two characteristic curves obtained as the measured value moves upward and downward across the entire measurement range of the instrument. When checking the hysteresis of a measuring instrument, the input value should be kept constant, and the two corresponding output values for the upward and downward strokes should be measured; the maximum difference between these values for the same input signal represents the hysteresis.
Enter a fixed value to measure the maximum difference in output at the upper and lower travel limits.
1. Under constant external conditions, when the same instrument is used to measure a certain parameter in both forward and reverse directions, the difference between the readings obtained is called hysteresis. The magnitude of the hysteresis is generally expressed as a percentage, which is the ratio of the maximum difference between the readings of the instrument during forward and reverse strokes, under the same value of the parameter being measured, to the instrument’s range. It includes hysteresis and dead zone. 2. There are many reasons for backlash, such as gaps in the transmission mechanism, friction in moving parts, and the effect of elastic hysteresis in elastic elements ； The size of the hysteresis reflects the precision of the instrument; therefore, it is required that the hysteresis of the instrument do not exceed the allowable error specified by its precision class