Raising the Standard of Temperature Measurement

Precision thermometry manufacturer ASL (UK) has upgraded its market leading range of AC bridges with the launch of the F252 as a successor to the highly popular F250.

ASL has been producing the industry’s leading high precision thermometers and temperature bridges for over 40 years. Its equipment is used for primary and secondary calibration verification, process monitoring, sterilisation and validation work by some of the world’s most demanding end users including NASA, Boeing, Shell, Esso and all International Standards Laboratories including the National Physical Laboratory.

The ASL F250 Precision Thermometer has been a leading reference temperature standard worldwide for a number of years. Thanks to further advances in technology, ASL has now replaced it with the F252, which is the
fastest commercial AC Bridge of this precision class and faster than any DC bridge of similar specification.

It boasts accuracy to within +/-0.01ºC (full range) and resolution of 0.001ºC (0.0001Ω) with a resistance range of between 0 - 400Ω. It is also the first AC Bridge to be launched with ‘smart probe’ capability.

The F252 also comes with two channels as standard, but four and six channel variations are available with each channel able to work with up to 72 user-defined probes so providing spot on calibration. The F252 also offers single, differential and alternative measurement modes.

The establishment of the RoHS Directive (Restriction of Hazardous Substances) across Europe in 2006 prompted a review of all thermometry devices. The tight restrictions placed on lead, mercury and cadmium have meant that all thermometer manufacturers have had to adapt some of their approaches.

“This actually presented us with a real opportunity,” says ASL technical manager Peter Andrews. “We are continually reviewing our product offering, but the emergence of the RoHS proposals back in 2003 prompted us to take a new direction.

“The outcome is a much more environmentally sustainable range of products, which create fewer waste disposal problems, and, at the same time, deliver a new standard in precision thermometry with better features than ever. It also provides the user with improved reliability and longer life than its predecessors because it uses solid state switching and has no mechanical components.”

The F252 is capable of measuring temperature ranges to meet ITS90, CVD, EN60751 & IEC751 standards and results are delivered via a LCD backlit display with large numeric, statistical or graphical information. It also comes with USB interface as standard, but optional RS232, IEEE or LAN interfaces are also available.