Instrumentation Calculators

# Instrument Calibration Verification Calculator

An instrument calibration verification calculator confirms that instruments provide accurate and precise measurements by comparing their performance to a predefined standard.

The following is a thorough example of a pressure transmitter calibration with five points.

1. Instrument Reading: The value provided by the instrument being tested.
2. Standard Value: The value from a reference standard or calibration standard.
3. Tolerance: The acceptable range of error for the instrument.
4. Full-Scale Range (FSR): The maximum range of the instrument.
1. Error: The difference between the instrument reading and the standard value.
2. Percentage Full-Scale Error: The error expressed as a percentage of the full-scale range.
3. Pass/Fail: Whether the instrument is within the acceptable tolerance.

Check if the absolute value of the percentage full-scale error is within the specified tolerance.

Let’s perform a calibration verification example for a pressure transmitter that operates within a negative to positive range. We’ll assume the following details:

• Full-Scale Range (FSR): -50 psi to 50 psi
• Standard Values (Reference Pressure): -50, -25, 0, 25, 50 psi
• Instrument Readings: -49, -24, 1, 24, 51 psi
• Tolerance: ±1% of full scale (1 psi)
• Full-Scale Range (FSR): 100 psi (since -50 to 50 psi gives a range of 100 psi)

• Standard Value: -50 psi
• Error: −49−(−50)=1 psi
• Percentage Full-Scale Error: (1/100​)×100=1%
• Pass/Fail: Pass (within tolerance)
• Standard Value: -25 psi
• Error: −24−(−25)=1 psi
• Percentage Full-Scale Error: (1/100)×100=1%
• Pass/Fail: Pass (within tolerance)
• Standard Value: 0 psi
• Error: 1−0=1 psi
• Percentage Full-Scale Error: (1/100)×100=1%
• Pass/Fail: Pass (within tolerance)
• Standard Value: 25 psi
• Error: 24−25=−1
• Percentage Full-Scale Error: (−1/100)×100=−1%
• Pass/Fail: Pass (within tolerance)
• Standard Value: 50 psi
• Error: 51−50=1 psi
• Percentage Full-Scale Error: (1/100)×100=1%
• Pass/Fail: Pass (within tolerance)

The calibration verification of the pressure transmitter is successful in this case because every data point falls within the designated full-scale error tolerance of ±1%.

By using this method the accuracy of the instrument is verified throughout its whole operating pressure range from negative to positive providing accurate readings for crucial applications.