calibrating thermometers-resistance thermometry bridges & Temperature Calibration software

If you are seeking a precision thermometer or a resistance thermometry bridge, or plan to set up a new in house temperature calibration laboratory facility to bring your organisation up to ISO17025 standards, or maybe to bring this facility back in-house, we offer our advice & guidance on the most appropriate model, based on our 20+ years experience in temperature measurement & calibration.

We offer a wide range of RTD probes with various lengths & diameters to chose from, including primary standards referencing thermometers for disseminating the ITS90 temperature scale & also referencing standard thermocouples.

If you require a temperature calibration heat source, we supply a wide choice of metal block baths to choose from, spanning different temperature ranges from -80°C up to +1200°C, enabling you to calibrate subordinate thermometers against a traceable reference thermometer. Full details on these temperature block baths can be found here on the Temperature Calibrating Drywell Block Baths page or Temperature Liquid Calibration  Baths here.

Please request a copy of the product data sheet, either by phoning 01767 692692, email or use the Contact us link, filling in the details as required.

If you also like the idea of automated temperature calibration, then the Caliso Temps software makes this easy.

You may like to download the free Guidelines for obtaining the best performance from RTDs, Prt's and Pt100’s in particular, a Sensing Devices (SDL) Ltd publication.

NPL Temperature Measurement and Calibration Course, 4 - 6 October 2010: You can register here.

Precision Digital Temperature Calibration Thermometers & Resistance Thermometry Bridges
F900 Super Primary Standards Thermometry Bridge The ASL Model F900 is designed specifically for resistance thermometry to provide you with the best possible accuracy. Accuracy: 20ppb (+/- 5 micro K)
F18 Primary Standards Thermometry Bridge The ASL F18 includes a wide range of features specifically tailored for temperature metrology. Accuracy: 0.1ppm (+/- 25 micro K)
F700 Secondary Standards Thermometer Bridge Accuracy: +/-5 micro K over full range Resolution:0.25 micro K over the full range.
F600  Secondary Standards AC & DC Thermometer Bridge Accuracy: up to ±0.5mK Resolution: 0.1mK DC version for Thermistors measurement.
F500 A/C Bench Top Thermometer Accuracy: ±0.005°C, ±5mK, over the full range (Typically ±0.001°C, ±1mK, at 0.01°C) Resolution: 0.001°C /0.0001°C Temperature ranges: -200°C to +962°C 25R & 100R Internal reference resistors (user or auto selectable)
Platinum Resistance Thermometers (Prt's) Full range of Platinum Resistance Thermometers (PRTs) for use in every application, from standards calibration to site temperature measurement.
Precision External Standard Reference Resistors A range of Standards Reference Resistors for use as an external reference resistor when calibrating Platinum Resistance Thermometers using precision A/C bridges.
DDM 1000 Precision Bench Top Digital Thermometer Accuracy:10mK (Pt100) Resolution:0.1mK DDM1000HRL Accuracy: 0.3mK (Pt100) Resolution: 0.02mK
DDM900 Precision Bench Top Digital Thermometer 2 Channels, option up to 8 internal channels. Accuracy: ±10mK Resolution: 1mK, optional 0.1mK
T4200 Precision Bench Top Digital Thermometer Accuracy: +/- 10mK Resolution: 0.001°C
F252 Precision A/C Digital Bench Top Thermometer. Accuracy: +/-0.01°C over the full range. Resolution: 0.001°C / 0.0001 Ohms. Temperature ranges: -200°C to +962°C. Display update rate: 500ms to full instrument performance.
F200 Precision Digital Thermometer Accuracy:0.01°C Resolution:0.001°C
F150 Bench Top Digital Thermometer for Prt's & Thermocouples. Built in Battery for Field Applications. Data Logging. Expandable up to 4 channels. Accuracy High accuracy: up to ±0.01°C. Resolution:up to 0.001°C.
F100  Digital Thermometer Accuracy:0.02°C Resolution:0.001°C
F100 Digital Thermometer Deals: Two F100 deals are available, call us on 01767 692692 to request details.
T905 Bench Top Digital Thermometer The T905 Bench Top Instrument for Pt100, thermocouple types J, K, L, N, R, S, T. Measuring Range: -200°C to + 1760°C Accuracy: +/- 0.1°C Resolution: 0.1°C RS232 Digital output 0-1VDC Analogue output Integrated sensor calibration.
T955 Bench Top Digital Thermometer The T955 Bench Top Instrument for Pt100 & thermocouple types J, K, N, L, R, S, T, Humidity & Airflow. Measuring Range : -200°C to +1760°C 0-100% rH 0-40m/s Accuracy +/-0.03°C +/-1.5% rH +/-0.5m/s
P795 Precision Hand Held Digital Thermometer/Logger with "tare" function. 2 Channels for 4 wire Pt100 probes. Accuracy:0.015°C (-50C ..+199.99°C) otherwise 0.025% Resolution: 0.001°C. (0.01°C above +199.99°C) Memory with real time clock...approx 6000 measurements. "Smart probes" available (calibration data stored in eprom).
Automated Temperature Calibration Software "It does what it says on the tin" Caliso Temps is made up of 2 separate programs: Laboratory Interface where you connect your instruments and carry-out your calibration. A wide range of manufacturers hardware are supported, including web- cam support for equipment such as LIG thermometers or digital indicators which have no digital interface. Builder where you analyse your data, perform calculations & also design your own calibration certificates.

Making precise temperature measurement or validating temperature products has never been easier with the precision thermometry systems we supply.

Over 20 years experience in supplying temperature measurement & calibration products to industry & UK National Laboratories.

          Please request a copy of the product data sheet, either by phoning 01767 692692, email or use the Contact us link, filling in the details as    

          required.

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In choosing the correct hand held digital thermometer it is important to consider the uncertainties that can be permissible (uncertainty budget) for the measurement process.

If we are to use a precision digital thermometer for calibration of other subordinate thermometers, then the system accuracy of the reference precision thermometer, over the working temperature range of the device under test or calibration, will need to be at least 3 to 4 times better.

In general the accepted method of calibrating thermometers is to immerse both the reference thermometer ( probe) & the thermometer under test (probe), in either  a metal block temperature calibration bath (sometimes referred to as a drywell block bath calibrator), or in a stirred liquid calibration bath, which is known as calibration by comparison. Both types of baths have their own merits (& associated costs).

For calibration of primary  referencing thermometers, (national standards laboratory maintained at NPL in the UK) & secondary standards laboratories (UKAS accredited), temperature calibration of individual thermometers is carries out by immersing a high purity platinum precision resistance thermometer (SPRT) or a high purity working standard thermometer, into fixed point cells, which have extremely precise known temperature values: triple point of water at 0,010000°C, melt point of gallium, freezing point of indium, tin, zinc aluminium, silver, gold & copper at 1084.620°C. Sub zero values are derived from the mercury triple point at -38.83440°C to the hydrogen triple point at -259.3467°C. Silver point being the highest value for realising temperature using the Platinum Resistance Thermometer in the

ITS 90 temperature scale.

Usually the resistance thermometer is connected to a direct temperature read out high precision thermometer such as the ASL F600 or Dostmann DDM1000 etc. or to a precision resistance thermometry bridge where the resistance of the thermometer is measured and then balanced against either an internal or an external high precision four wire precision resistor The resistance bridge then indicates a resistance ratio value to several decimal places. This value can them be converted back into temperature by look up tables of resistance to temperature values.

For industrial applications, temperature calibration will normally be carried out in house in its own calibration laboratory, with trained personnel skilled in temperature measurement & calibration & having a reference thermometer traceable to a UKAS lab (ISO Calibration), or sent out to a UKAS accredited temperature calibration lab.

It is important when considering a calibration lab to use that it has not just a UKAS "traceable certification" but is also UKAS or ISO certified for temperature calibration, using either a liquid or metal (drywell) calibration block bath, & not just UKAS traceable for electrical simulation, as the indicator & temperature probe needs calibrating as a system.