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Laboratory Electronics

Calibration of measurement sensors, calibration ordering, devices ordering

Information about calibration methods used in the LAB-EL Laboratory

Humidity, temperature and pressure sensor calibration Humidity, temperature and pressure laboratory

ORDER PLACEMENT

1. Instruments calibrated in the LAB-EL Laboratory

Measurement sensor calibration in the scopes defined in the Scope of Accreditation of the Calibration Laboratory No. AP 067 compares responses of the calibrated (checked) instrument with the response values of a control instrument under a set conditions.

The Laboratory calibrates instruments in which the measurement signal from the sensors is converted to a form allowing for an unequivocal read-out of the measurement result in one of the following ways:

  • onto a digital display integrated in the instrument,
  • onto a digital display associated with the instrument,
  • through an unequivocally defined digital interface in the form of a numerical result (e.g. read-out by computer software or another associated electronic device),
  • through a measurement of an unequivocally defined analogue system, usually used in industrial automation, e.g. direct current (4…20) mA, direct voltage (0…1) V, (0…10) V or the like,
  • through a measurement of direct voltage (-70…+70) mV on terminals of thermoelectric sensors (thermocouples),
  • through a measurement of resistance for pt100 sensors — platinum industrial resistance thermometers (sensors of resistance thermometer).

The Laboratory calibrates and adjusts instruments, both, manufactured by LAB-EL, as well as by other manufacturers, as ordered by external clients.

The Laboratory does not calibrate mercury-in-glass nor mechanical thermometers.

2. Order placement for the delivery of devices

When ordering devices please fill in the information query, which will enable us to select devices for a given application:

  • Type of measurements to be conducted.
  • Requested measurement range, resolution and uncertainty.
  • Number and quantity of measurement points.
  • Distance between measurement points.
  • Requested means of transmission and read-out of measurement data.
  • Is the continuous recording of measurements on a computer required?
  • Expected location and mode of operation.
  • Is instrument Calibration Certificate from the Accredited laboratory required?

A price list of our products and services is available from our website: http://www.label.pl/po/cennik.html.

A detailed description of our products is provided in leaflets available in our website: WWW.LABEL.PL.

In order to obtain a detailed individual offer, please fill in the inquiry form with full contact details:

  • full identification details of the company placing the order,
  • full contact details (first name, surname, email address and phone number).

When placing orders, the following details are required of the ordering party:

  • details of the ordering party (name, address, Tax ID No. (NIP)),
  • details of the collector (first name and surname of the person authorised to collect, phone number, company name, delivery address).

If an order includes a calibration service at the Laboratory, please provide the following additional data, required for the calibration certificate:

  • details of the Applicant (name, address),
  • details of the User (name, address).

3. Calibration order

If an order includes a calibration or testing service at the Laboratory, please describe in details, as per requirements:
a) the metrological and technical characteristics of the object for calibration/testing,
b) scope and type of services (calibration/testing) — in particular:

  • the number of control points,
  • the range of the quantity measured,
  • the limits of the basic response error of the object for calibration/testing,
  • the uncertainty of determining basic response errors,
  • calibration or calibration and adjustment,
  • deadline of calibration objects submission,
  • means of delivery and collection,
  • documents required for delivery with calibration objects,
  • the method of presenting and delivering the calibration/testing results,
  • the method of formally accepting the order for calibration/testing.

If the ordering party does not describe the requirements in details, we assume that the order covers standard calibration, according to the service presented in our price list.

If the ordered calibration service (in part or in full) exceeds the scope of our Laboratory’s accreditation, we offer modified calibration and testing services in external laboratories accredited via LAB-EL, and according to the price list.

In order to obtain a detailed individual offer, please fill in the inquiry form with full contact details:

  • full details of the ordering party,
  • detailed contact details (first name, surname, email address and phone number),

When placing orders, the following details are required of the ordering party:

  • details of the ordering party (name, address, Tax ID No. (NIP)),
  • details of the collector (first name and surname of the person authorised to collect, phone number, company name, delivery address),
  • details of the applicant to whom the calibration certificate is to be issued (name, address),
  • data of the User for issuance of calibration certificate (name, address).

A recommended sample of a Calibration Service order, together with general terms and conditions for service provision, as well as a price list enabling calibration cost estimation are presented in separate documents:

CALIBRATION METHODS

The calibration methods outlined below are discussed in detail in the respectively assigned procedures, which the LAB-EL company shares with its clients for inspection at the company’s seat, at ul. Herbaciana 9 in Reguły.

4. Thermometer calibration method

The thermometer calibration is performed in thermostats in a calibration bath, in dry thermostats or in a climatic chamber.

Calibration in a thermostat is employed especially when calibrating thermometers with external temperature sensors — providing the mechanical design of the temperature sensors allows for this. The control and calibrated thermometer sensors are placed in a calibration bath with forced circulation of liquid or in a dry thermostat. The sensors are placed in openings of a metal block to equalise the temperature distribution, which is then fully submerged in the calibration batch or placed in the dry thermostat. The sensors are placed as close to each other as possible.

In accordance with the calibration subject and temperature, the calibration is performed with the use of one of the methods described in the instructions:

  • LW.SOP-13: Electronic Thermometer Calibration;
  • LW.SOP-15: Platinum Sensors of Industrial Resistance Thermometers;
  • LW.SOP-21: Instrument Calibration outside the Laboratory;
  • LW.SOP-27: Thermometer Calibration in Liquid Nitrogen.

Calibration in a climatic chamber is performed when the mechanical design of the calibrated thermometer does not allow it to be placed in a thermostat — i.e. when the calibrated instrument is large, does not feature external sensors, the temperature sensor (with humidity sensor) is located together with the electronic circuit inside the instrument’s case, or when the instrument’s design permits its usage only for the temperature measurement of air and gases alone.

In accordance with the calibration subject and temperature, the calibration is performed with the use of one of the methods described in the instructions:

  • LW.SOP-13: Electronic Thermometer Calibration;
  • LW.SOP-14: Calibration of Instruments for Measuring Relative Humidity and/or Air and Gas Temperatures: Thermo Hygrometers, Hygrometers, Thermometers and Wet-and-Dry Bulb Thermometers.

5. Pyrometer and thermal camera calibration method

Pyrometer and thermal camera calibration is performed with a calibrated pyrometer or camera directed onto a model IR radiation source.

The calibration is performed according to the method described in the instructions:

  • LW.SOP-23: Pyrometer Calibration.

6. Thermo hygrometer calibration method

Hygrometer, thermo hygrometer, dew point hygrometers and wet-and-dry bulb thermometer calibration is performed in a climatic chamber. The calibrated instrument (or only its sensor) and the sensor of the control thermometer for measuring air temperature, and the sensor of the control hygrometer for measuring dew point are placed in a climatic chamber with forced air circulation during calibration, which emulates conditions of specified relative humidity and temperature.

The calibrated and control instruments (or their sensors) are placed together, in order to minimize the influence of parameter heterogeneity in the operating space of the climatic chamber.

The calibration is performed according to the method described in the instructions:

  • LW.SOP-14: Calibration of Instruments for Measuring Relative Humidity and/or Air and Gas Temperatures: Thermo Hygrometers, Hygrometers, Thermometers and Wet-and-Dry Bulb Thermometers.

7. Dew point hygrometer calibration method

Dew point hygrometer calibration is performed in a climatic chamber. The calibrated instrument (or only its sensor) and the sensor of the control hygrometer for measuring dew point are placed in a climatic chamber with forced air circulation during calibration, which emulates conditions of specified relative humidity and temperature.

The calibrated and control instruments (or their sensors) are placed together, in order to minimize the influence of parameter heterogeneity in the operating space of the climatic chamber.

The calibration is performed according to the method described in the instructions:

  • LW.SOP-22: Calibration of Instruments for Measuring Dew Point of Air and Gases.

8. Barometer and differential manometer calibration method

Manometer calibration is performed by connecting the calibrated (tested) instrument and the control instrument (or their sensors), and the pressure setter in order to create a common pressure measurement system, with the use of special flexible pneumatic hoses (plastic pipes). If the technical design of the calibrated instrument does not allow it to be connected with the measurement system with the use of a pneumatic hose (the instrument does not feature a stub connector for pneumatic hoses), the instrument is placed in an air-tight container that is connected to the pressure measurement system.

Manometer calibration in a climatic chamber is performed when the client’s order stipulates the microclimatic conditions (temperature, relative air humidity) in which the instrument should be checked and if the conditions differ in comparison to the Laboratory’s ambient conditions by: ±2°C in the case of temperature or ±5% in the case of relative humidity. The tested instrument (or only its sensor) and the sensors of the control thermometer and hygrometer are placed in a climatic chamber during testing, which emulates conditions of controlled temperature and relative humidity.

The calibration is performed according to the method described in the instructions:

  • LW.SOP-18: Calibration of Instruments for Pressure Measurements.

9. Anemometer calibration method

Anemometer calibration includes checking the responses for a known air flow speed induced in a wind tunnel, which is measured indirectly with the use of two measurement methods:

  • for low speeds — on the basis of differential pressure measurement at both sides of metering orifice, installed in the wind tunnel, and calibrated on the basis of differential pressure measurement on a standard impact tube;
  • for high speeds — on the basis of differential pressure measurement at standard impact tube and on the basis of differential pressure measurements between the nozzle of the wind tunnel and the surroundings of the wind tunnel.

The laboratory station for anemometer calibration is described in detail in a separate description.

The calibration is performed according to the method described in the instructions:

  • LW.SOP-29: Anemometer Calibration.

10. Climatic and thermostatic chamber, and laboratory bath calibration method

The aim of the chamber calibration is to determine the following:

  • measurement of temperature parameter deviation and (in the case of a climatic chamber) the relative humidity inside the chamber against the temperature and humidity values set on instrument indicators that are integral to the chamber;
  • temperature heterogeneity and stability measurement and (possibly) relative humidity in the chamber;
  • measurement of the influence of the chamber walls radiation effect on the temperature sensor measurement results;
  • the influence of the level of chamber closing with the objects inside the chamber on the calibration results;
  • the uncertainty values of the calibration results.

If requested by the client, the calibration may be performed for one location of the sensor within the chamber — but this does not determine uncertainty and heterogeneity components in the entire chamber.

The calibration is performed according to the method described in the instructions:

  • LW.SOP-25: Climatic and Thermostatic Chamber, and Laboratory Bath Calibration. 

ADDITIONAL INFORMATION

11. Checking instruments before adjustment

If possible, prior to adjustment, calibration of the instrument is performed additionally:

  • in the case of thermo hygrometer calibration in standard points — in one point: 22°C, 57% RH (in the case of a thermometer calibration, it includes only temperature, in the case of hygrometer — relative humidity);
  • in the case of barometer calibration in standard points — in one point: 940 hPa or 980 hPa;
  • In the case of non-standard calibrations — prior to adjustment the calibration is performed at the point where the calibration will be performed after adjustment, or another calibration point is agreed with the client according to the client’s requirements.

Prior to adjustment the calibration is not performed if:

  • the client opted out of such calibration in the calibration order (e.g. the client does not require it);
  • the technical condition of the instrument when submitted to the Laboratory (e.g. when it is damaged) makes it impossible to perform calibration (after repair of the instrument, additional calibration prior adjustment is not performed).

Checking prior to adjustment allows the client to estimate the instrument drift between calibrations.

12. Instrument adjustment (regulation)

If the client has specified in the order that the instrument should be calibrated with adjustment (i.e. regulated in order to minimize its response errors), the adjustment is performed after a positive preliminary check (point 6) but prior to the performance of a metrological check (calibration, point 8). The instruments manufactured by LAB-EL (structurally adapted for electronic adjustment) prior to every subsequent re-calibration are always subject to adjustment unless the client opts out of this service in the order.

Adjustment is performed according to separate procedures, described by the manufacturer of the measuring instrument. In the case of instruments manufactured by LAB-EL, the adjustment procedure is specific for the Laboratory. In the case of instruments manufactured by other entities, the adjustment instructions for a given instrument should be provided by the client when the order is placed.

13.  Calibration (check-up) control points

If the client does not specify in the calibration order the values of the humidity and temperature control points (in the case of calibrating instruments for relative humidity and/or air temperature measurement) or pressure control points (in the case of barometers), standard calibration points, as stipulated in the Price List mentioned in point 14, are adopted. The procedure for control points is performed with the accuracy of ±0.3°C in the case of temperature, and ±1% in the case of humidity unless other values are determined in the client’s order.

14. Calibration result

The proof that a sensor or a measuring instrument has been calibrated, according to the requirements of PN-EN ISO/IEC 17025:2005 General Conditions for Competency of Testing and Calibration Laboratories is the Calibration Certificate, covering all obtained results, issued according to the sample of the Polish Centre for Accreditation and according to the Scope of Accreditation of the Calibration Laboratory No. AP 067.

The Laboratory may provide information as to whether a measuring device or sensor is efficient and whether it fulfils the technical requirements according to the ILAC-G8:03/2009 guidelines. These guidelines were elaborated in order to assists testing and calibration laboratories all over the world in determining and presenting the compliance of the quantitative measurements with the specification. In order to meet the requirements set forth in ISO/IEC 17025, laboratories should submit to the clients reports with the measurement results, uncertainty data and, if required, an estimation of compliance with the manufacturer’s technical data specifications. Compliance estimation is performed according to the above guidelines for a client’s individual order.