Technical dictionary / Glossary
Adjusting of measuring equipment
precise setting of a measure value via a professional intervention in the measurement system.
Adjusting the weighing range of a balance
either with the external test weight via the adjusting program (CAL), or with the internal automatic adjustment resp. adjusting switch. It is necessary with variations in temperature, a change of environmental conditions, change of location etc. Recommended as a daily check routine.
Animal weighing program
When the animal moves during the weighing process, a stable average value is obtained by using the HOLD key. This value remains "frozen" until the HOLD key is pressed again. ➔ Vibration-free weighing
Allowance for measuring uncertainty during practical use of a balance. Is given in the appendix to the DKD calibration certificate.
documentation of measured characteristics of balances or test weights and of traceability to the national standard. Additional price.
Calibration of measuring equipment
determination of the precision of a measure value without intervention in the measurement system. Example: to check a balance you load a test weight upon it. The term "Calibrating" was formerly also used for adjusting.
Calibration or verification
Calibration can be carried out on any balance which is in perfect working order. Calibration is a private service controlled by the state for ensuring high quality requirements according to DIN EN ISO 9000ff and other standards, e. g. in production and research.
Verification can only be carried out on type-approved balances which carry the green M ➔ Verification
a bar lights up to shop the currently selected and optionally available weighing range
Written confirmation that a service has been provided in accordance with a defined requirement.
Amongst other things, this can be a metrological statement as well as an ISO factory certificate, or any another lasting endorsement.
In the field of verification you receive a verification certificate and a calibration certificate in the DKD/DAkkS.
Confirmation of the achievement or compliance of a predetermined standard, such as a DIN standard such as DIN EN ISO 9000 ff. (Quality management) or DIN EN ISO/IEC 17025 (Accreditation), or a build-type approval for balances.
Commercial error limits
See reverification of balances and weights
Conformity declaration from the manufacturer
The manufacturer declares that the product fulfils the applicable EU directives. With electronic balances this is always in conjunction with the CE mark.
Procedure for confirming warranted characteristics in accordance with recognised rules. For balances this relates to verification.
Control of measuring equipment in the QM system in conjunction with quality standards
An organisation certified to a quality standard such as DIN EN ISO 9000 ff. e. g. a production plant is obliged to adhere to a defined quality standard within the framework of its quality management system. To do this, it is imperative that you have measuring equipment which is working accurately.
DIN EN ISO 9001, December Edition 2008 states in section 7.6 "Guidance of monitoring and measuring equipment", that measuring equipment must be calibrated at defined intervals and before use. The measuring devices and measuring standards needed to do this must:
- be traced back to international or national standards.
- their measuring uncertainty must be known
- they must be marked with a clear identification
- the test must be documented
The Calibration fulfils all these requirements.
Counting of single pieces
Determining a quantity by weighing. This is possible if the pieces to be counted are roughly the same weight. To do this, you establish a reference weight and then you can weigh the pieces to be counted. Counting balances display the weighed pieces as number of items immediately. All counting balances can be switched from counting to weighing mode.
The counting resolution is calculated in points from the ratio of the weighing range [Max] divided by the smallest part weight. It is a statement of counting accuracy.
To connect the balance to a printer, PC, network or a second balance. The interfaces available are stated in the model description. Typical interfaces are, for example, RS-232, USB, LAN, DUAL, Digital I/O etc. The interface parameters can be set using the balance.
One of the main areas of application for laboratory balances is determining densities, e.g. determining the specific weight of liquids and solids. To do this you will need a highly accurate precision balance and a density set.
It is particularly convenient if the balance can calculate and display the density right away. It has become apparent that by means of weigting when in the process of etermining the density of liquids and solids according to
the buoyancy method particularly accurate results can be obtained (Archimedes’ principle).
a) Density determination of liquids: By means of measuring the buoyancy with a glass plummet with known volume immersed in the liquid to be measured
b) Density determination of solid bodies: The sample is weighed once in air (A) and then in an auxiliary liquid of known density (B). The density of the solid (ρ) is calculated as follows:
- ρ = A/(A-B) × ρ0
- ρ = Density of sample
- A = Weight of sample in air
- B = Weight of sample in auxiliary liquid
- ρ0 = Density of the auxiliary liquid
- a) Pre-packaged goods control, whenever a product is sold according to its volume [cm3]. This volume is calculated with weight [g] : density [g/cm3].
- b) Materials analysis
- c) Density of porous materials
Protective device against air movements for very accurate weighing procedures. Required for analytcial and precision balances with readout d ≤ 1 mg.
the complete weighing range of a balance is divided and starts with Readout d1. Beyond this fine range the Readout d2, usually 2 x d1. The change-over occurs automatically.
Electromagnetic compatibility (EMC)
Immunity to interference, e. g. of a balance against errors on the display caused by electromagnetic emission in the vicinity.
External test weight
for adjusting or checking the balance accuracy. Adjusting the weighing range. The external test weight can be DKD calibrated at any time, even afterwards
These options can only be carried out in the KERN factory.
Filter for adaptation to the ambient conditions
vibrations are compensated due to an increase of the measurement cycles within the balance, this means an extension of the integration time.
Good Laboratory Practice, also see ISO/GLP
Gravitational acceleration➔ Gravitational force
very important influence for precise electronic balances. Due to the varying influence balances have to be adjusted at the location of use.
HACCP = Hazard Analysis and Critical Control Points
The HACCP concept is a preventative system, which is designed to guarantee the safety of foodstuffs EC regulation 852/2004 mandates the use of the HACCP concept for all companies which are involved with the production, processing and sales of foodstuffs.
Infrared data interface To transfer data from the measuring instrument to a printer, PC or other peripheral devices.
Internal test weight
like test weight external, but installed in the balance and powered.
Quality Management System in the form of a DIN Norm for quality assurance in a factory.
Quality Assurance Systems demand record keeping of weighing results and the correct adjusting of the balance giving details of date, time and balance identification. The easiest way of obtaining this documentation is by means of a connected printer.
Linearity / precision greatest deviation of the weight display of a balance to the value of the respective test weight in terms of plus and minus over the whole weighing range.
Manufacturer's declaration of conformity
this documents that a product meets the EC directives. With electronic balances always in conjunction with CE mark.
Balance contains memories, e.g. for item data, weighing data, tare weights etc. ➔ PLU
lower limit of the verifiable weighing range. Is marked on the verification plate. The function of the balance is also given below the minimum load.
total weight of all components of a mixture without the weight of the tare cup.
Optimisation of counting ➔ Optimisation of reference weight
Optimisation of reference weight when piece counting
The reference weight is generated automatically several times during the counting process. Increases the counting accuracy.
Example: reference weight prior to drying: 50g = balance display 100 %. After drying 40 g = balance display 80 % absolute (dry mass) or 20 % relative (humidity).
temperature measuring errors are possible with readings either side of the limits. With verified balances this is stated on the identification plate.
of single pieces when weighing e. g. 10 identical pieces; the reference quantity is 10. The balance automatically indicates the average weight per piece. As from now each loading of identical pieces to be counted will be directly indicated as the quantity of pieces. The following applies: The higher the reference quantity, the higher the counting accuracy.
PRE-TARE ➔ Automatic taring
Proof of compatibility
This documents the verification compatibility for combinations of weighing modules such as display devices, load cells and connecting elements.
Quality management ➔ Control of measuring equipment
Smallest readable weight increment on a digital display
Smallest readable weight increment on a digital display
Recipe level A
Separate memory for the weight of the tare container and the recipe ingredients (net total).
Recipe level B
Internal memory for complete recipes with name and target value of the recipe ingredients. User guidance through displays.
= Standard deviation the measure of conformity in repeat weighing (e. g. balances) subject to the same conditions. Mostly 1 d or less. Quality feature.
SC-TECH ➔ Single cell technology
Analytical balance with a readout d = 0,01 mg.
Single cell technology
The load cell consists of a single aluminium block, which gives a very high measuring quality. ➔ FORCE
Smallest part weight when counting
The smallest piece weight, which a balance can accept for piece counting. For the relevant model, enter "g/piece" in the product data table.
= Reproducibility the measure of conformity in repeat weighing (e. g. balances) subject to the same conditions. Mostly 1 d or less. Quality feature. ➔ Uncertainty of measurement of a balance
When not in use, these balances are partially switched off automatically, and when this happens there is no warm-up time when you switch them back on.
Tare deduction ➔ Automatic taring
when the tare pan is put in place the balance immediately displays zero. Saves time.
the available weighing range of a balance is reduced by the value of the tare load. Example: weighing range of a balance Max 6000 g, Tare (= container) 470 g, available weighing range 5530 g.
Test weights: classes of accuracy
and their general relation to the types of balances:
- E2 the most accurate test weights for high resolution analytical balances of verification class I ≥ 100.000 e
- F1 Precision weights for analytical balances/ precision balances for verification class I/ II, up to 100,000 e
- F2 Test weights for precision balances of verification class II, up to 30,000 e
- M1 Precision weights for industrial and commercial balances of verification class III, up to 10,000 e
The lower and upper limiting values are programmed individually. Input is possible in gram, pieces or %. With tolerance checks such as dosing, portioning or sorting, the balance displays the value over or under the limits. (also see Weighing with tolerance ranges)
various individual weighings are added automatically to aggregate, e. g. all individual weighings of a batch. Net-total weighing: weight of tare cup and weight of components memorized in two separate stores.
Totalising level C
Internal memory for complete recipes with name and target value of the recipe ingredients. User guidance through displays. Additional convenient functions, such as barcode and back calculation functions.
Traceability to the National Standard
A pre-requisite for every perfect measurement is the validated comprehensive proof that the measuring equipment can be traced back to the international or national standards. In Germany the statutory binding standards are available from the PTB.
Uncertainty of measurement of a balance
determined for each balance according to a precisely given test method and documented in the Calibration certificate. It depends on various factors both internal and external. With increasing weight the uncertainty of measurement rises
Documented proof, which provides a high degree of assurance that a process or procedure is suitable to fulfill a specific task.
According to the EU directive 2009/23/EG, balances must be verified if they are used as follows:
- in commercial trade when the price of a commodity is determined by weighing
- in the manufacture of pharmaceuticals in pharmacies and analysis in pharmaceutical and medical laboratories
- for official purposes
- in the production of prepackaging
- in medical applications
Every balance is tested by the metrological service and stamped with a verification mark. Its accuracy within the framework of permissible standard tolerances is thereby confirmed. EU verification applies to all member states of the EU.
Verification categories of balances
Class I – Analytical balance (precision balance)
Class II – precision balance
Class III – industrial scale (commercial scale)
Verification validity for balances
Generally 2 years for all verification categories, for control balances generally 1 year, after expiry the balance has to be reverified.
measure of the verification tolerance, depending on balance, mostly between 1 d and 10 d
Verification value [e]
measure of the verification tolerance, depending on balance, mostly between 1 d and 10 d ➔ Readout
Weighing range [Max]
is the working range of the balance. The balance can be loaded up to the specified upper limit.
Weighing with tolerance range = Checkweighing
The lower and upper limiting values are programmed individually. Input is possible in gram, pieces or %. With tolerance checks such as dosing, portioning, sorting, Fill-to-target, classification the balance displays the value over or under the limits.
for KERN balances between the platform and display device using the integrated radio module. Range within line of sight depending on the model, approx. 10 - 20 m