The latest reference torque transducer from HBM, the TB2, utilises the principle of axial shear to provide increased accuracy and very low measurement uncertainty, especially with the temperature effect on zero, the linearity deviation and the reproducibility. Specifications for the relative standard deviation of repeatability is <±0.01 %, the temperature effect on zero is <±0.02 %/10K and the linearity deviation, including hysteresis, is <±0.03 %. This places the TB2 in the top category for accuracy of 0.05 as defined by DIN 51309 or EA-10/14. The transducer complies with HBM’s definition of accuracy class of 0.03.
The use of high-precision torque transducers is very important, because the requirements for measuring torque and its transfer quantities are becoming increasingly stringent. Companies that are certified – or wish to be certified – to ISO 9000 have to prove traceability to national standards. The requirement covers all measuring and test equipment used for assuring the quality of a company’s products and aims to ensure that consistently accurate measurements are given.
The standard TB2 measurement system is quasi-hermetically sealed and can optionally be provided protected to IP67 as defined by EN 60529. This design feature of the measuring body, combined with fitting strain gages on the inside of the measured structure, means that the measurement system is optimally protected against external environmental effects.
The TB2 reference torque transducer is designed for non-rotating use in both static and dynamic measurements. It is available in six nominal (rated) measuring ranges: 500 Nm, 1 kNm, 2 kNm, 3 kNm, 5 kNm, and 10 kNm.
The system enables all amplifier systems for strain gage full bridges to be used. Transducers are integrated into the complete measurement chain from HBM through the amplifiers. For high precision work, HBM recommends using the DMP 40 digital precision measuring device or the ML38B precision amplifier module in conjunction with the TB2.
HBM’s amplifiers enable different PC interfaces and fieldbus systems to be connected easily giving users the complete measurement solution from a single source, from the transducer through signal conditioning and the analysis software.