temperature measurement:precision digital calibrating thermometers, thermometry bridges & Automated Temperature Calibration software from Dostmann Electronic, Automatic Systems Laboratories (ASL) & Humpage Technology

If you are looking to replace an existing thermometer or thermometry bridge, or intending to set up a new in house temperature calibration laboratory facility to bring your organisation up to ISO 9000 standards, or maybe to bring this facility back in-house, we can offer you our advice and guidance on the most appropriate precision thermometer or resistance thermometry bridge to achieve this, based on our understanding of your uncertainty budget.

We offer a wide range of temperature probes with various lengths and diameters to chose from to complete the reference thermometer system, including primary standard reference thermometers from Chino.

If you require a temperature calibration heat source, we have a range of metal block temperature calibration baths for you to choose from, spanning different temperature ranges from -40C up to 1200C, enabling you to calibrate subordinate thermometers against your reference thermometer. Full details on these block baths can be found on the Temperature Calibration Block Baths page.

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 will enable you to achieve it.

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

Precision Digital Temperature Calibration Thermometers & Resistance Thermometry Bridges
ASL F900 Super Primary Standards Thermometry Bridge The Model F900 is designed specifically for resistance thermometry to provide you with the best possible accuracy. Accuracy: 20ppb (+/- 5 micro K)
ASL F18 Primary Standards Thermometry Bridge The F18 includes a wide range of features specifically tailored for temperature metrology. Accuracy: 0.1ppm (+/- 25 micro K)
ASL F600  Secondary Standards AC & DC Thermometer Bridge Accuracy: up to ±0.5mK Resolution: 0.1mK DC version for Thermistors measurement.
ASL F700 Secondary Standards Thermometer Bridge Accuracy: +/-5 micro K over full range Resolution:0.25 micro K over the full range
ASL Platinum Resistance Thermometers (Prt's) ASL provides a full range Platinum Resistance Thermometers (PRTs) for use in every application from standards calibration to site temperature measurement.
Precision Reference Resistors ASL provides a range of Standards Reference Resistors for use as an external reference resistor when calibrating Platinum Resistance Thermometers using precision A/C bridges.
Dostmann DDM 1000 Precision Bench Top Digital Thermometer Accuracy:10mK (Pt100) Resolution:0.1mK DDM1000HRL Accuracy: 0.3mK (Pt100) Resolution: 0.02mK
Dostmann DDM900 Precision Bench Top Digital Thermometer 2 Channels, option up to 8 internal channels. Accuracy: ±10mK Resolution: 1mK, optional 0.1mK
Dostmann T4200 Precision Bench Top Digital Thermometer Accuracy: +/- 10mK Resolution: 0.001°C
ASL 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.
ASL F200 Precision Digital Thermometer Accuracy:0.01°C Resolution:0.001°C
ASL 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.
ASL F100  Digital Thermometer Accuracy:0.02°C Resolution:0.001°C
ASL F100 Digital Thermometer Deals: Two deals are available, call us for full details.
Dostmann 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.
Dostmann 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
Dostmann P795 Precision Hand Held Digital Thermometer/Logger with "tare" function. 2 Channels for 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...appr 6000 measurements. "Smart probes" available (calibration data stored in eprom).
Caliso "Temps"  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.

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 digital thermometer for calibration of other subordinate thermometers, then the system accuracy of the reference 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 system ( probe) and the thermometer under test (probe), in either  a metal block temperature calibration bath (sometimes referred to as a drywell block 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 primary  temperature calibration (national standards maintained at NPL) and secondary standards laboratories (UKAS accredited), temperature calibration of individual thermometers is carries out by immersing a high purity platinum precision resistance thermometer or 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 a Platinum Resistance Thermometer in the ITS 90

Temperature Scale.

Usually the resistance thermometer is connected to a direct temperature read out bridge such as the ASL F600 or Dostmann DDM1000 etc. or to a 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, which the 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.

For industrial applications, temperature calibration will normally be carried out either at an in house temperature calibration laboratory, with trained personnel skilled in temperature measurement and calibration and the lab will probably have UKAS accreditation, or off site at a UKAS laboratory, or at least a laboratory with a reference thermometer traceable to a UKAS lab (ISO Calibration).

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