How to choose calibration management software


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 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.

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 (eg 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:

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:

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:

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:

Consider the following:

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:

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.

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:

Consider these questions:

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:

Traceability and record keeping requirements

A system can provide traceability to:

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:

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 (eg 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:

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:

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:

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.

Numbers Of Assets And Transaction Volumes

To manage 100 instruments or gauges as an end-user in a single site, a home-made spreadsheet (eg Microsoft EXCEL) or database (eg 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:

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.



  • 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
  • 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
  • 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
  • Copyright Richard Tatlow - 08/06/2003