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What kind of information needs to be in a calibration record?

#11
What's the difference between the two?
The official results from the VIM (International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (VIM):

calibration
operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties and, in a second step, uses this information to establish a relation for obtaining a measurement result from an indication

In plain terms, you compare an instrument to a traceable standard and make a determination from the results.

verification
provision of objective evidence that a given item fulfills specified requirements
NOTE 1 When applicable, measurement uncertainty should be taken into consideration.
NOTE 5 Verification should not be confused with calibration. Not every verification is a validation


What's the difference? A bit formal in that calibration speaks towards measurement traceability and includes measurement uncertainties. Verification leads to more of a pass / fail type of result.

Of course, they had to throw in validation:
validation
verification, where the specified requirements are adequate for an intended use
 

Jim Wynne

Super Moderator
#12
I think there is a reduced set of conditions that have to be met for verification vs. calibration.

One thing I have seen are 'records' stating that 'calibration' occurred, yet the records did not indicate environment at time of the event, or standards used, or their calibration status. Standards such as ISO 17025 requires a controlled environment, among other things. I didn't find those to be effective records, then.

At another shop, they have a list that gets signed where they check a gage pin before taking it from the bin with the available calibrated micrometer. They sign the pin was verified before use.

Calibration can be done in house, but like everything else, the operator must be qualified, the correct tools must be available and fit for function, and the procedure must be established and appropriate.
Calibration is comparison to a master source, nothing more.
 

Jim Wynne

Super Moderator
#13
The official results from the VIM (International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (VIM):...
I'm familiar with the VIM definitions. The problem is that they're functionally meaningless unless at least two parties have agreed to make them normative. Confusion is almost always the result when people try to redefine simple terms to fit their own agendas. Calibration is comparison to a standard.
 
#14
"Confusion is almost always the result when people try to redefine simple terms to fit their own agendas."

Kind of like when someone says "Calibration is comparison to a master source, nothing more."
Oh, how I wish it were that simple.
 

Jim Wynne

Super Moderator
#15
"Confusion is almost always the result when people try to redefine simple terms to fit their own agendas."

Kind of like when someone says "Calibration is comparison to a master source, nothing more."
Oh, how I wish it were that simple.
No, it's nothing like that. There might be things that need to be done as a result of calibration (adjustment, uncertainty calculation, etc.) but those things are not universal requirements for defining the act of calibration. Calibration isn't different from verification; it's a type of verification.
 
#16
It gets confusing because people have used the terms interchangeably forever. You yourself asked "What's the difference between the two?" But they are different.

Calibration is when you take a unit and compare it to a standard, and you derive a relationship between the two.

Verification is when you compare the results you get on a unit to a tolerance or specification. You determine a pass / fail result.

You send instruments to NIST for calibration, they give you results such as the mass of a weight, the voltage of a standard cell, the value of a standard resistor, etc. They include their measurement uncertainty. They do not determine in or out of tolerance, just what the value is.

You send your instrument to Keysight, Troemner, Mitutoyo, Fluke, etc. and they will do a verification. They will compare it to a standard and determine if it is in or out of tolerance.
 

Jim Wynne

Super Moderator
#18
Calibration is when you take a unit and compare it to a standard, and you derive a relationship between the two.
Which is what I've been saying all along.

Verification is when you compare the results you get on a unit to a tolerance or specification. You determine a pass / fail result.
Your definition of "verification" is a verification of the measured object, not of the device used to measure it. Calibration is a form of verification.
 
#19
Which is what I've been saying all along.


Your definition of "verification" is a verification of the measured object, not of the device used to measure it. Calibration is a form of verification.
Not quite.

What I quoted was the definition:
"verification
provision of objective evidence that a given item fulfills specified requirements
"

When I get a Calibrated mass back it gives the value as being 1.000032 g with a measurement uncertainty.
When it gets back from a Verification it says that it Passes for a Class 2 1g mass.

There is a difference. In most cases a customer wants a Verification that their instrument was in tolerance, not the value of the Calibration result.
 
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Jim Wynne

Super Moderator
#20
Not quite.

What I quoted was the definition:
"verification
provision of objective evidence that a given item fulfills specified requirements
"

When I get a Calibrated mass back it gives the value as being 1.000032 g with a measurement uncertainty.
When it gets back from a Verification it says that it Passes for a Class 2 1g mass.

There is a difference. In most cases a customer wants a Verification that their instrument was in tolerance, not the value of the Calibration result.
So you're saying that verification is a result of calibration?
 
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