How to Choose Calibration

Management Software

(This article is Copyright Richard Tatlow B.A. M.Sc. - 08/06/2003 )

Introduction
There are many software packages on the market which are put into the categories 'calibration management
Software' and 'gauge management software'. In my view we should distinguish between
• Calibration management software
• Calibration laboratory management software
• Measuring equipment manufacturer software
• Calibration software

Calibration management software is used by owners of measuring equipment to maintain quality assurance
standards relating to the use of such equipment in their organisation.
Calibration laboratory management software is used by subcontract calibrators for order processing and job
control in their calibration laboratories.
Measuring equipment manufacturer software is used to confirm fitness for use and provide traceability for
equipment leaving a manufacturer's premises.
Calibration software is used (by anyone) with a computer-based calibration system and is generally used in
conjunction with, or as part of, the first three types of software. It comes in various forms, ranging from fully
integrated computer-driven calibration systems to simple computation programs or spreadsheets requiring
manual input of readings.
Calibration software plays a significant role in calibration laboratories. However, it will be irrelevant in calibration
management systems where calibration results are not required to be part of the calibration records maintained
by the system. This would apply where all calibration is subcontracted and subject to certification or where
individual calibration measurements are of no interest to the owners and users of the measuring equipment.
On the other hand, calibration measurements and error values are of direct interest to the calibration
management system user who wishes to use error or wear trends to assess the condition of measuring
equipment and make decisions concerning its value, reliability and usefulness.
Of course, many calibration laboratories issue reminder/recall lists to customers, but, in my view, this does not
represent calibration management in anything other than a superficial sense.

This article is concerned mainly with the first category of system - calibration management software for owners of
measuring equipment - with references to calibration software where it could be of interest to those owners who
do some of their own calibration.
There is a wide range of physical environments, operational practices, calibration requirements and IT resources
to be found across industry, all of which affect the calibration management system best suited to a particular
organisation. Consider, for example: a large automotive component manufacturing plant; an aerospace company;
a pharmaceutical manufacturing plant; a small turned-part machine shop. If you looked at a successful calibration
management installation in each of these you would find different critical features.
It follows that when considering the purchase and installation of a new computer-based calibration management
system, you should make a careful evaluation of your own system functional requirements before assessing the
market offerings.
This article outlines some of the main issues which could affect your choice of system and then presents a check
list which you can use as a basis for software package comparison and evaluation.

Retriever Technology Ltd Page 1 of 10

Not all the features and influences mentioned here will be of interest - indeed, half of them will probably be
completely irrelevant to your circumstances and requirements. By the same token, glowing references or
derogatory comments concerning a particular package from another user, whose requirements or environment
differ from yours, may not be pertinent to your situation. As mentioned above, a system suitable for a
pharmaceutical company or an aerospace company might be useless in a small turned-part company and vice-
versa.
This article does not attempt to cover all the general issues that surround the selection, installation and
implementation of a computer system. The assessment of IT resources in relation to any proposed software
package (system capacity, networks, internet and intranet communications, operating systems, database servers,
hardware, etc.) should be carried out by your IT Department. They may impose constraints on your range of
choice.
Note that a calibration management software package might simply consist of an off-the-shelf spreadsheet or
database system set up and maintained using in-house resources.
Finally, remember that there is no point in specifying functional features that require manual data entry (e.g. to
track gauges around the plant, control their recall with real-time usage, record calibration results, etc) if the
manpower to do this is not available.
The term measuring equipment (assets for short) includes gauges, instruments, calibration equipment, control
devices, meters, probes, thermocouples - in fact anything that measures something.

Outline Approach

There are 6 main steps to take before proceeding with system implementation:

1. Describe your starting point and existing practice in detail

2. Establish any constraints affecting future operation of the system
3. Draw up a detailed functional specification of your requirements
4. Detail any proposed changes to working practices
5. Agree these with your management, colleagues and IT department
6. Evaluate your options for implementing the system

This article is primarily concerned with step 3, although there are a few other points worth noting. There follows
narrative on some of the main issues that might arise and the article finishes with a feature check list.
Having drawn up your check list you need some systematic method of comparing your options. A simple scoring
system might be suitable.
Bearing in mind that your requirements and calibration practices may change as you become more familiar with
any particular system, create a feature rating list - for example:
A = 5: we must have this feature
B = 3: we will probably need this feature in the future
C = 1: we might need this feature in the future
D = 0: this feature is of no interest to us
and grade your check list accordingly.
If you then evaluate the market offerings against this check list and give each candidate a score such as:
0 = not available
1 = coming soon (so we are told)
2 = acceptable
3 = more or less what we want
4 = exactly what we want
Multiply the feature ratings by the candidate scores and total the results for each candidate.
This type of approach is subjective but it gives you a rational basis for comparison and discussion.

Starting Point

There are 4 main categories of starting point:

• manual card-index systems

Retriever Technology Ltd Page 2 of 10

 • legacy software systems written specially for the user
• software packages not capable of meeting changing requirements
• standard database or spreadsheet packages

Consider the following:

Integrity and timeliness of existing records - are they up-to-date?
Existence of obsolete records - do we need them all?
Transfer existing computer records to a new system - is this possible?
Access to old records - can we keep the old system for reference?
With manual records you can pick and choose what you put into a new system. If your existing records are
computer-based then this may be the time to filter out all the obsolete items. If the current database is in some
proprietary format or on a mainframe it may or may not be possible to extract the data in a form suitable for
transfer to a new system. If you are using a standard database or spreadsheet then there should be no problems
in transferring the data.
Calibration records generally fall into 6 categories:
Physical attributes (asset number, description, status, etc.)
Recall details (asset, type of control, interval, date due, etc.)
Calibration event (asset, date, pass/fail, etc.)
Calibration details (asset, date, numerical measurements)
Calibration equipment traceability (asset, date, standards, etc.)
History (asset, date, location, event, etc.)
You should consider the practicality and desirability of transferring each of these 6 categories of records, if they
exist. In cases where the old and new databases may be incompatible, information about previous calibrations
and history perhaps can be consolidated into a single 'notepad' type of record in the new system.
Hopefully, the supplier of the software package that you select will be able to offer a data migration service to
move your existing data into the new database so that you end up with the best possible starting point in the new
system.
The other key consideration at your starting point is your existing investment in calibration equipment.
Replacement of older calibration equipment with up-to-date technology capable of direct computer links is likely to
cost far more than the calibration management software. If you are thinking of investing money in new calibration
equipment then decide upon the equipment and its calibration software before looking at calibration management
software.
Asset Types And Calibration Methods
There are significant differences in the way that gauges and instruments are calibrated dependent upon their type
and location. If you wish to record calibration results then this system aspect should be considered.
Fixed mechanical gauges are usually calibrated using nominal dimensions with absolute upper and lower
tolerances. The calibration is carried out using external equipment which measures the relevant static
characteristics and no 'input' is involved. Computations to derive characteristics such as effective thread
diameters may follow.
Variable dimensional gauges are also calibrated by measuring reference standards for comparison with a series
of nominal values using absolute upper and lower tolerances. Computations to derive characteristics such as
maximum errors may follow.
Electrical, thermal and pressure instruments, on the other hand, are dynamic systems with analogue inputs and
outputs subject to all kinds of physical disturbance. Errors are usually measured in percentage and proportionate
terms expressed as percentages of input values or total range.
Calibration of control devices such as pressure switches usually takes the form of a series of checks that the
device triggers within preset input limits.
Devices such as linear transmitters require computations to compare actual output values with predicted output
values based on the input value.
In some cases, where, for example, an instrument is fixed in line, the input values used for calibration may vary
from calibration to calibration.
The point is that if you wish to record numerical calibration measurements with tolerance comparisons then check
that the system caters for whatever type of input, output, tolerance and computation you use.
If you need to record 'as found' and 'as left' calibrations for adjustable instruments then make sure that the system
allows this.

Retriever Technology Ltd Page 3 of 10

Calibration Equipment
Calibration equipment is a major issue only if you wish to have a single integrated management system which
also stores calibration measurements.
The type of calibration equipment used will vary with the type of gauge and instrument and their locations.
Equipment lacking any facility for communicating measurement data to the outside world requires manual input of
results.
Some very sophisticated calibrators have been developed together with software to 'drive' them, especially in
non-mechanical instrumentation applications. If you use this type of equipment then your choice of calibration
software may be limited to the manufacturer's own offering, although many of the calibration equipment
manufacturers offer 'open' interfaces so that third-party software can be used.
Some calibration management software includes facilities to record numerical measurements directly from
calibration equipment - often through a serial port.
Not all equipment manufacturers offer suitable calibration management software and even where they do, you
may still use calibration software from more than one manufacturer. This could preclude a completely integrated
system. In this case consider the possibility of using a separate calibration management system. It may be
preferable to have best possible system for your calibration management even if this means using independent
and unlinked calibration systems.
It is not uncommon to find 2 separate calibration management systems side by side in the same organisation.
One takes measurements from a dimensional calibrator and controls dimensional gauges. The other is linked to
electrical instrument calibrators and controls electrical instrumentation.
Uncertainty Of Measurement
Complicated uncertainty of measurement computations are not commonplace outside calibration laboratories
particularly where only a small number of pieces of calibration equipment are used. A simple statement of
uncertainty on each calibration record derived from the values for the calibration equipment usually suffices.
However, if you wish to compute uncertainty each time you calibrate then the system should include the relevant
procedures.
Location of assets and movement tracking
The physical location of the assets and the movement between locations is a major factor in your choice of
system.
With fixed in-line gauging and instrumentation, minimum down-time and cost considerations may dictate that
calibration is performed with the item in situ. Modern instrumentation can communicate with central computers
and implement automatic calibration procedures but localised work is still usually necessary to complement this.
Typical set-ups include:
• Pen and paper
• Purpose built portable calibrator for in-line instrumentation
• Lap-top/PDA with/without wired/wireless network connection
• Instrumentation computer holds detailed calibration results locally
• On-the-spot printed certificates
Consider these questions:
Does the portable unit need a calibration schedule?
Do results need to be transferred back to the host system?
Do results need to be stored in the calibration management system?
If you are managing assets on more than 1 site then location tracking and the ability to filter by location is
essential together with the ability to produce a list of assets due for calibration at a single site.
If you need location tracking, or wish to recall assets for calibration based upon time spent in use, number of
issues or production counts, then the system must record each movement in a timely fashion and enable job
details and production counts to be recorded.
If you have a separate gauge store then the storeman will need a workstation and (in my view) a simple booking
in/out program.
The following points should be considered:

Retriever Technology Ltd Page 4 of 10

Will the system record issues/receipts whilst calibration is in progress ?
Will shop-floor operatives self-issue items?
What happens when the storeman is absent?
Will assets be transferred between non-store locations?
Do we use kits?
Do we have equivalent assets which can be issued as substitutes?
Would the use of bar-codes be helpful?
Will the system issue assets due for calibration?
Traceability and record keeping requirements
A system can provide traceability to:
• calibration equipment and reference standards
• locations
• products, processes, batches and jobs
• operators and inspectors
• environmental conditions
Such traceability will only be available if the relevant data is put into the system, so it is important to define your
requirements in this respect. Also, traceability will only be available if historical records are maintained.
Traceability goes beyond calibration but your calibration management system may be a vital component in the
overall traceability system in your organisation.
Calibration equipment and reference standards traceability is usually obtained by recording the items used to
calibrate each asset. These items themselves will be in the system database, because they are also calibrated
with traceability. The traceability chain works backwards through your system and out into your subcontractors'
systems. Where in-house calibrations take place the following should apply to each calibration record:
record each item of calibration equipment used (e.g. portable calibrator)
record each reference standard used (e.g. resistance, set of slips)
record the calibration status of each of these items
It is useful if you can, at any time, list all calibrations carried out using a specified piece of calibration equipment
or reference standard in a specified time period.
Location traceability involves an audit trail showing where an asset was at all times during its life. This is fairly
easy to handle if the asset is fixed in position (e.g. an in-line gauge or transmitter) and only moves for repairs, but
is more difficult for things like hand gauges and probably impossible for gauges carried around by inspectors.
Traceability to products, processes batches and jobs is necessary in many safety critical industries. Again an
audit trail is required, but in many instances, the calibration management system will be used to complement data
maintained in the organisation's production control system. For example, the production control system will record
exactly when and where a product batch was made whilst the calibration management system will record,
independently, what instruments and gauges were involved in manufacturing that product batch with their
relevant status.
It follows therefore that to provide this type of traceability; the system must include procedures to list all assets in
a specified location on a specified date, together with audit trails for each item.
Traceability to operators, inspectors and environmental conditions refers to calibration activity and not
production activity. Calibration records can include this information.
Statistical analysis requirements
The most useful types of reports in this area include:
• inventory by asset status
• inventory by asset calibration condition
• numbers of gauges and instruments calibrated in a period
• estimated cost of calibration in-house
• estimated cost of subcontract calibrations
Other analysis can give error and wear charts showing errors over a complete calibration or historical trends
which can be useful in setting calibration intervals.
Storage and integrity of historical records
The following may be relevant:

Retriever Technology Ltd Page 5 of 10

 • storage of individual historical calibration records
• storage of individual historical location tracking records
• historical traceability to calibration reference equipment
• historical traceability to locations, jobs, products, inspectors, etc.
• search recall and review of historical records
• ability to amend calibration records
• audit trails of record amendments
In some environments, a note of the most recent calibration suffices. At the other end of the scale, a complete
history of an asset including details, with dates and times, of calibrations, movements, repairs, inspections, etc. is
mandatory.
Normally, historical records should not be amendable by users. If amendments are allowed then examine your
audit trail and protection requirements. In some environments, to enable simple mistakes to be corrected (how
many times have you entered data without looking at the screen?), the most recent calibration record can be
amendable. At the other end of the scale, for example where FDA standards are applied, any permitted
amendment must be documented in an audit trail.
Paper trail, certificates and signature constraints
If you rely on electronic storage for historical record-keeping then ensure that you can view and print any relevant
record. If you lose an original hard copy or need extra copies then you must be able to print one.
If signatures form part of a document's integrity then you need to do one of the following:
keep a signed hard copy original
obtain an authorised signature on printed hard copy
use an electronic signature system
store electronically a scanned copy of the hard copy original
Environmental monitoring and recording procedures
Calibration rooms are generally environmentally controlled with respect to temperature and humidity. Whilst
independent climatic controllers and recorders may be used, the current conditions may need to be logged with
each calibration record for easy reference. Any variation of a condition outside the prescribed limits should be
notified to the user.
This can be done manually or by connecting one of the system workstations to an appropriate environmental
probe.
If the system records these environmental variables then a review procedure is required which confirms the
historical record with any deviations outside the specified limits highlighted.
Calibration measurements can be adjusted using a computation based on the difference between the current
environment and some specified reference value.
Printed calibration labels, colour coding and tagging
It is common practice for gauges and instruments to be tagged or colour coded in some way to show current
calibration status and calibration due date. This may not be essential if you have a proper computer-based
identification and control system in operation, but many users prefer a 'belts and braces' approach which allows
any user of an asset at any time to know if that asset can be used without referring to a computer workstation.
Also, if an asset is calibrated for a specific or limited use, or part-calibrated, then this information must be
attached to the asset.
Although printed labels may appear to be an attractive option using special-purpose label printers, hand-written
labels are often the solution, because the range of labelling materials available for printed labels (polyester or
special papers) may not be suitable for gauges and instruments used in adverse (hot, dirty, oily, abrasive)
conditions. Also remember that labels are often produced one-at-a-time.
Electronic transmission of reports and calibration results
Recall lists of assets due for calibration will be produced at regular intervals. If these reports are to be distributed
to other departments, sites or, in the case of calibration laboratories, customers, then it is often more convenient
to do this by email.
If assets are being calibrated by a subcontractor, whilst the user maintains a calibration database, then much time
will be saved if the calibration certificate results can be transmitted electronically by email or magnetic media back
to the user. The user then imports the details into the system, storing the calibration record and updating the
recall information.

Retriever Technology Ltd Page 6 of 10

Numbers Of Assets And Transaction Volumes
To manage 100 instruments or gauges as an end-user in a single site, a home-made spreadsheet (e.g.
Microsoft EXCEL) or database (e.g. Microsoft ACCESS or FILEMAKER) is relatively simple to construct and
operate. To manage 1,000 assets properly an end-user will probably need a purpose built software package
with the ability to select, filter and sort records quickly. To manage 10,000 assets properly a user will almost
certainly need a purpose-built software package capable of handling large numbers of records securely and
reliably and using up-to-date database technology.
If large numbers of individual calibration or movement records are stored in the database then the software must
be capable of handling them without significant degradation of system response times or network traffic capacity.
Make some estimates of current record storage and traffic volumes for:
• Asset records
• Calibration activity
• Report production
• Location tracking

Then project these forward at least 5 years.

IT resources

A single-user system requires a stand-alone workstation. A multi-user system requires a network, usually with a
database server. The maintenance and support capability required for a network server based system will
generally require in-house IT support. A multi-user system spread across physically remote sites requires the
right type of communications network to function effectively.
It is possible to use company intranets and/or the internet with a browser to interrogate and update a calibration
database. Whilst this might seem to be an attractive technical feature, you would be well-advised to consider
carefully the pros and cons of using this method in place of a dedicated application program.
If you plan to implement a system with more than a few thousand records across a network that extends beyond
the immediate vicinity, seek the advice of your IT department and ensure that they satisfy themselves with regard
to the ability of the existing IT system and the application program to function efficiently and reliably.
As with any proposed software installation, an IT feasibility study is essential when evaluating prospective
candidates. Ensure that the prospective application software suppliers provide all technical information necessary
for your IT department's assessment.
Data back-up security is an important consideration. It will be preferable to have a system which will work with a
database located on a network server which makes daily back-ups without the intervention of the calibration
management system supervisor.

Retriever Technology Ltd Page 7 of 10

A2Z Calibration Management Software Features Checklist
Database

Asset register, type descriptions, status and condition

Recall control(s) - fixed/variable interval and/or issues/counts
Calibration records and history - calibration due dates
Traceability to calibration equipment and reference standards
Event history
Site, Location and job tracking
Standard descriptive lists for types, locations, etc
Users and inspectors
Printed and electronic certificates
Electronic document filing
Pictures and images
Calibration procedures
User-definable descriptive items and/or notepads
Environmental records
Colour codes
Asset groupings - kits, loops, test rigs, drawing cross-references, etc.
Asset capital and calibration costs
Subcontractors
Calibration times taken
Holiday/working calendar
Constraints on data storage and processing volumes

Retriever Technology Ltd Page 8 of 10

Functionality

Asset record and control maintenance

Asset search and selection of asset subsets with filters
Automatic overdue status update
Blank results sheet
Recording an internal calibration: with/without results; as
found/as left; attributes
Recording an external subcontractor calibration with certificate
Uncertainty of measurement
Sentencing an asset after calibration with comments
Recording calibration equipment used with its calibration status
Changing a control interval for all assets of a specified type
Location tracking - stores issue/receipt procedure
Control recall using fixed/variable interval
Control recall using actual issued time/issues/counts
Allowance for weekends, holidays, shift working, etc.
Traceability playback and analysis
Designing and producing printed certificates
Historical record retrieval
Password protection and access control
Protection against calibration record amendments
Protection against issuing assets out of calibration.
Wear/error charts and trends - predicted remaining asset life
Printed labels/tags
Temperature, humidity and pressure environment monitoring
Grouping assets (production drawings, loops, kits, test rigs, etc)
Substitution of equivalent assets
Designing and recording tailored calibration measurement
procedures
Communication with bench calibrators and instrumentation
Transfer of data between database and portable calibrators/units
Electronic transfer of data between database and subcontractor
Electronic signatures
Subcontractor certificate scanning
Bar-code recognition
Email facilities
Transfer of data from legacy systems
Multiple concurrent user access to database
Archiving of obsolete data
Calibration procedure and calibration standard display
Routine security back-up of data and restoration procedure
Internet/intranet access to data
Asset audits by location

Retriever Technology Ltd Page 9 of 10

Reports

Recall reports for selected asset subsets and locations

Calibration overdue lists
Filtered lists of assets
Traceability for calibration equipment, personnel and products
Inventory by number, value, location, status
Asset status reports
Calibration activity reports
'Where used' lists
Audit trails
Flexible reporting
Database interrogation using external reporting tools

Miscellaneous

Ease of use
Ability to tailor
Clarity of system information
Upgrade availability
Technical support facilities
Training options
Price v budgetary constraints
Data security and system validation
Data import/migration service and export/migration feasibility

This article is Copyright Richard Tatlow B.A. M.Sc. - 08/06/2003

Retriever Technology Ltd Page 10 of 10