Calibration Question and Answer

Calibration Question and Answer

1. What is calibration?
Calibration is a set of operations that documented comparison of the measurement device to be calibrated against a traceable reference standard/device.

2. What is calibration certificates?
The calibration certificate is the official document authorized for the calibration of instruments and provides traceability to the National Institute of Standards and Technology.
The calibration certificate is issued by most businesses as a historical record. However, some enter data on the certificate in a local database to track the status of their test equipment inventory.

3. What is the difference between a Standard (Traceable) and Accredited
Calibration Certificate?
Standard (Traceable) Certificate: Instrumentation is calibrated to specifications with traceable standards. A full data report is optional with the calibration certificate.
Accredited Certificate: meets the ISO / IEC 17025 requirements and the accrediting body of the laboratory. The unit under test is calibrated within the authorized scope of accreditation of the supplier in accordance with ISO / IEC 17025.

4. What are the different types of calibration?
Transducer calibration
Data system calibration
Physical end to end calibration

5. How frequently an instrument should be calibrated?
Calibrate instruments on the basis of manufacturer recommendation.
Before and after critical measuring project
Monthly, quarterly, or semiannually

6. Why calibration should be carried out?
Calibration describes the precision and efficiency of the measurement obtained using a machine component. Over time, machinery begins to drift from its precision when it uses specific techniques or tests particular parameters such as heat and humidity. And:
Calibration keeps process safe
Machine Calibration can help to reduce costs from manufacturing errors

7. Briefly describe how to calibrate a linear instrument?
Linear instrument calibration is so-called as the Zero-span method. Procedure:
Apply the low range value (LRV) to the instrument and note the reading.
If there is an irregularity in the reading, rotate the Zero adjustment until the instrument is
accurately registered at this point.
Now apply the upper range (URV) value to the instrument and note the reading.
Rotate the span adjustment until the instrument displays the correct reading of the URV if the
readings do not function properly.

8. What Is Reynolds Number?
Answer : We know with help of reynolds number what type of flow in fluid.

9. Why Do We Use 4-20ma Signal Instead Of 0-10 Ma?
Answer : To elevate zero so that we can come to know whether it is dead zero or from signal.

10. What Is The Difference Between Dry Leg And Wet Leg?
Answer : Dry leg means in lab. And wet leg means in feild

11. How Can We Calibrate A Positioner?
Answer : A positioner is a device put into a valve to ensure that it is at a correct position of opening  as per the control signal. An I/P converter only sends the opening/closing request to valve  but can not confirm its position.
Positioner senses the valve opening through a position feedback link connected to valve   stem which is its input signal. I/P converter output is its setpoint input. The difference  between these two is the error signal based on which the positioner positions the valve to  correct position to reduce error to zero. Hence positioner is nothing but a pneumatic  feedback controller.
Controlled external supply air to positioner provides power to positioner to position a valve.  Also positioner is used in a valve when valve operating signal range is different from I/P  converter output range


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