Choosing the Right Calibrator Webinar Presented by Druck BHGE and Transcat

Copyright 2019 Baker Hughes, a GE company, LLC ("BHGE"). Druck and logo are
registered trademarks of BHGE in the United States and other countries. All
product and company names are trademarks of their respective holders.
How to choose the right
Portable Process Calibrator
Sponsored by Transcat, Inc.
Presented by Stephen Sajben, Sr Product Specialist – Druck BHGE
September 26, 2019

How to choose the right Portable Process Calibrator?
September 26, 20192
 Scope of Discussion
 Defining Goal or Primary Objective of Calibration
 Defining Approach to achieving Goal
 Equipment Selection Criteria to support approach/philosophy
 Conclusions/Recommendations
Agenda

Copyright 2019 Baker Hughes, a GE company, LLC ("BHGE"). All rights reserved.
Scope of Discussion

94
Scope of Discussion
Laboratory Calibration Field Calibration

September 26, 20195
Calibrate
• To standardize (something, such as a
measuring instrument) by determining the
deviation from a standard so as to ascertain
the proper correction factor1
Calibration
• The act or process of calibrating: the state of
being calibrated1
Calibrator
• A device used in calibrating something
A brief comment on ‘Calibration’ and ‘Calibrators’
The term ‘Calibrator’ can sometimes be viewed as
misnomer as they do not always have capability to
‘adjust’ output values of a DUT/UUT. For the
purposes of this discussion the term will be used a
device that facilitates calibration.

Defining Goal or
Primary Objective

97
Calibrations may potentially be required for a
number of different purposes, or for multiple
purposes:
• Process Performance or Optimization
• Safety
• Quality Assurance
• Compliance
– (Government Regulation, Industry Regulation, Corporate Policy,
Other)
• Maintenance/Preventative Maintenance
• Functional Testing
Defining Goal(s) or Primary Objective(s) in Calibration

Defining Approach to
achieving Goal

99
The purpose(s) driving calibration requirements will define
required attributes of the calibration equipment to be used.
Calibrator attributes and other considerations can include but
are not limited to:
• Parameters
• Performance
• Documentation
• Utilization
• Ease of Use/Implementation
• Price vs Cost
Defining Approach to achieving Goal

Parameters

91
Parameters
The most common parameters covered by portable Process Calibrators are:
• Electrical – Voltage (mV, V), Current (mA), Resistance (Ω)
• Temperature – Thermocouple (TC), Resistance Temperature Detectors (RTD)
• Pressure –
• Frequency/Pulse Count -
Most portable process calibrator manufacturers cover these parameters.
There can be differences in ranges, types and uncertainties specified as well as
features and functionality.
Other parameters may require specific devices.

92
Parameters
Smart Transmitter Devices?
Many portable Process Calibrators today have Communicators
built into the device either as standard or as an option.
Communicators enable:
• Complete Calibration, i.e. device adjustment
• ‘Smart’ Features, e.g. re-ranging, suppression, diagnostics,
etc.. (if Communicator is fully functioning communicator)
HART, Fieldbus and Profibus are common smart
communication protocols.
Communicators require Device Drivers
(DD’s) to communicate with your device.
Be sure to check that Communicators
under consideration have the necessary
DD’s for your devices.

Performance

94
Performance
Measurement devices (transducers/transmitter, gauges,
switches, etc.) are specified differently than Calibration
devices.
• Measurement devices typically specified by Accuracy
• Calibration devices typically specified by Uncertainty
This can make evaluating required performance a challenge

95
Performance
To define ‘performance’ it is important to
define the terms used to express it
Definition of Terms
• Accuracy (vs Precision)
• Non-linearity, Hysteresis and Repeatability
• Uncertainty
• Standard, Combined and Expanded
• Resolution
• Traceability

September 26, 201916
Accuracy - Closeness of agreement between a measured
quantity value and a true quantity value of a
measurand1
Note:
Precision – Closeness of agreement between indications
or measured quantity values obtained by replicate
measurements on the same or similar objects under
specified conditions2
Accuracy for measurement devices is often expressed as
the combined effects (RSS) of non-linearity, hysteresis
and repeatability and expressed as ±X.XX% of span or
full scale
Definition of Terms

Non-Linearity – defined using
Best Fit Straight Line (BSL) – the
straight line that is ‘fit’, using a
‘least squares method’, through
all calibration points that
minimizes the maximum
deviation from the line.
O
/
P
Vin
O
/
P
Vin
1
2
O/
P
Vin
1
2
Hysteresis - the changes in
measured pressure as a percentage
of full scale when the pressure is
changed then returned to the original
value while keeping all other
environmental conditions the same
or compensating for them.
Repeatability - the spread of
readings when taking
consecutive measurements
without changing the pressure,
temperature or other external
environmental conditions.
A Root Sum Square (RSS) of the contributing factors is defined as the ‘Accuracy’ of the device.
Notes:
1) There is no required standard definition for the accuracy statement of measurement devices so there can be differences from
one manufacturer to the next. Definitions/Examples provided are typical
2) This defined Accuracy specification does not account for other potential error sources; e.g. thermal effects (changes due to
changing temperatures), long-term stability (changes in performance over time), etc..

September 26, 201918
Uncertainty
The word “uncertainty” means doubt, and thus in its
broadest sense “uncertainty of measurement” means
doubt about the validity of the result of a
measurement3
The formal definition:
• Non-negative parameter characterizing the
dispersion of the quantity values being attributed
to a measurand2
Definition of Terms
Note: the topic of uncertainty in measurement is a broad and sometimes complex subject and a detailed discussion is outside
the scope of our discussion today. There are numerous resources available online the most complete being the BIPM’s
(International Bureau of Weights and Measures) GUM – Evaluation of measurement data – Guide to the expression of
uncertainty in measurement. www.bipm.org

99
There can be multiple sources of Uncertainty of a particular
measurement:
• Test Equipment being used
• Test equipment it is calibrated against
• Actual UUT
• Environmental variations (temperature, humidity, air density, buoyancy, gravity, altitude, etc..)
• Methodology or procedures used
• Person performing the calibration
• and more…
The Combined Uncertainty is derived from statistical analysis of as many
relevant factors as can be determined and quantified.
Definition of Terms

90
Standard Uncertainty
• uncertainty of the result of a measurement expressed as
a standard deviation3
Combined Standard Uncertainty (CU)
• standard measurement uncertainty that is obtained
using the individual standard measurement
uncertainties associated with the input quantities in a
measurement model2
Expanded Uncertainty (EU)
• Product of a combined standard measurement
uncertainty and a factor (k) larger than the number one2
– EU = k x CU
Definition of Terms

91
Definition of Terms
Notes:
Values in () apply to DPI620G-IS models
1. Specification applies, 45 to 65 Hz and between 10% and 100% of full scale
2. Specification applies when calibration temperature is between 10 and 30°C
3. Total uncertainty includes reference standard uncertainty, NLH&R and typical
long term stability for one year (K=2)

92
Resolution
• Smallest change in a quantity being
measured that causes a perceptible
change in the corresponding indication1
Definition of Terms

93
Traceability
• Property of a measurement result whereby
the result can be related to a reference
through a documented unbroken chain of
calibrations, each contributing to the
measurement uncertainty1
Definition of Terms

How to choose the right Portable Calibrator?
94
Is all of this relevant or important?
…It depends…
Definition of Terms

Required performance can be a:
• Total Accuracy Ratio (TAR), e.g. 4:1 ratio of accuracy of UUT to calibrator
• Total Uncertainty Ratio (TUR), e.g. 4:1 ratio of uncertainty of UUT to calibrator
• Measurement Uncertainty Analysis (Mu), required for ISO 17025
• Probability of False Acceptance (PFA), required for Z540.3
Mu and PFA are not typically requirements in field calibration.
The generally accepted best practice of trying to maintain a TAR or TUR of 4:1 is more common.
Note: Uncertainty is a more stringent definition of performance than Accuracy. If comparing the Uncertainty
of the Standard (Calibrator) to the Accuracy of the device under test provide a 4:1 there should be a very high
level of confidence that the Standard (Calibrator) is appropriate for use.
Definition of Terms

Documentation

97
Documentation
Various levels of calibration documentation:
• Pen & Paper + Calibrator(s)
• Excel or Access + Calibrator(s)
• Generic Calibration Management Software +
Calibrator(s)
• Calibration Management Software + Compatible
Documenting
Calibrator (Paperless Calibration)
• Maintenance Management System + Calibration
Management Software +
Documenting Calibrator (Unified Calibration Solution)
Quality, Efficiency,
Productivity
Defects, Poor Products, Compliance
Issues

Pen & Paper + Calibrator(s)
28
Impossible to analyse data (requires addl step)
Advantages
Dis-advantages
Paper archiving (a lot of)
Reliance on calibration technicians
Need process to follow
Difficult to maintain and control
Labour Intensive
Large possibility of defects
Inexpensive to setup
Limited IT resources needed
Users don’t have to be computer literate

Excel (or Access) + Calibrator(s)
29
Difficult to maintain and control – need Excel or Access
expert
Inexpensive to setup
Advantages
Dis-advantages
Possible need to integrate with other software
Need experienced calibration technicians
Need process to follow
Legible and reduces/eliminates transcription errors
Records safe on backup system and relatively easy to
retrieve
Additional steps to analyse data

General Calibration Management
Software + Calibrator(s)
30
Maintained by Vendor
Advantages
Dis-advantages
Front-loaded effort to
integrate
Need experienced calibration technicians
Expensive
Level of control introduced by workflows in software
Data can be analysed

Utilization

92
Utilization
• How many technicians will be performing calibration?
• What is the frequency of calibration intervals?
• How can usage of calibrators be maximized?
• Is there sufficient modularity to provide flexibility of
ranges and accuracies to cover all requirements?
• How can calibrations be covered when equipment is
out for re-cal?

93
Utilization
One major determination to make in utilization considerations is whether to select a:
• Single function calibrator (or a number of them to cover all calibrations) or a
• Multifunction calibrator where one can cover a number of calibrations
P/loop + RTD/Loop + TC/Loop + Elec/Loop + Freq/Loop = Multifunction

Ease of Use/Implementation

95
Ease of Use/Ease of Implementation
• Does the calibrator cover all the parameters needed?
• Is the calibrator intuitive to use? Does it require extensive training?
• Is it similar to other calibrators currently in use or is it a dramatic change?
• Will it fit into current practices/capabilities or is there change required?
Fortunately, with developments of digital display technology many
calibrators are relatively easy to use and have intuitive interfaces as
well as on screen graphics and icons that make functionality simple.

Price/Cost

97
Price vs Cost
Cost = Value = Quality
Consider Economic Cost
Economic Cost ≈ Accounting Cost ($’s) + Opportunity Cost
(risk of gain vs loss)
Calibration equipment can be expensive and can be viewed
as purely an Accounting Cost, i.e. non-returning
investment. But there is always an Opportunity Cost
associated with properly performing, or not performing,
calibrations that should be appropriately balanced to
potential return.

Conclusions
/Recommendations

99
Recommendations
Steps to make the right choice:
1. Understand organizational calibration goals/objective
2. Develop approach to address goals/objective
3. Define selection criteria to support approach
4. Review multiple offerings by engaging vendor
5. Evaluate top contenders
6. Finalize decisions
7. Stay engaged with Vendor for aftermarket support
Conclusions/Recommendations

90
Goal/Primary
Objective
Performance Documentation Utilization Ease
of Use/ Ease of
Implementation
Cost
Ratio? Pen & Paper to
Software
Single Function vs
Multifunction
Seamless or Radical
Departure?
Price vs ROI?
Process Performance/
Optimization
High High Medium Low Low
Safety Dependent High Medium Low Low
Quality Assurance Dependent Med/High High Medium Medium
Compliance Dependent High Medium Low Medium
Maintenance/
Functional Test
Low Low/Med High High High
Custody Transfer High High Medium Medium Low
Rating(s) relative to return on investment

91
Unfortunately, there is no perfect Portable Process Calibrator that
will cover every parameter exactly the way every Technician wants
it to.
But, fortunately, there are many, many calibrators on the market
and through careful consideration and review an optimal solution
can be found.

Current Offer
Now through October 31st
• Save up to 25% on Druck DPI620 Genii
Multifunction Calibrator with trade-in
• Full details at: www.transcat.com/deals

Questions or Comments?
Email Nicole VanWert-Quinzi nvanwert@Transcat.com
Transcat: 800-828-1470
www.Transcat.com
For related product information, go to:
www.Transcat.com/ge-store

Questions?

Thank you!

Back Up

How to choose the right Portable Calibrator?
98
References
https://www.merriam-webster.com/dictionary/calibrate
International vocabulary of metrology – Basic and general concepts and associated terms (VIM) 3rd
edition
https://www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf
5http://asq.org/quality-progress/2009/03/measure-for-measure/standard-definition.html

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