Increasing Reliability by Regular Measuring Equipment Calibration   

What is Traceability?

Traceability means that a continuous chain of calibrations capable of being traced to the national standard must be proven and the measurement uncertainty of each calibration is known and documented. 

Calibration Laboratories

In practice, the national metrological institute (in Germany, the Physikalisch-Technische Bundesanstalt, PTB) cannot calibrate all measuring equipment used in industry due to capacity reasons. Because of this, accredited calibration laboratories are connected to the PTB via the national accreditation body of the Federal Republic of Germany (DAkkS). This implies that high-precision comparison measurements between the DAkkS laboratories and the PTB's calibration machines ensure that a Newton is consistently a Newton or a Newton meter always a Newton meter.

Force Transfer Standards

The U15 has proved its worth in the force range, covering measuring ranges up to 2.5 MN. The sensor is suitable for tensile and compressive forces. It is made entirely of stainless steel, hermetically sealed, and meets the requirements of the IP67 degree of protection. According to ISO 376, the class accuracy is 0.5*. The U15 measuring range guaranteed by HBM is exceptional: Class 0.5 is maintained from 10% of the maximum measuring force up to the full-scale value.

_{*Class accuracy 0.5 according to ISO 376 does not signify that the measurement error is 0.5% of the measured value. In fact, ISO 376 distinguishes 4 different quality classes regarding the transducers’ ability in terms of repeatability, hysteresis, creep, and other parameters. The transducers with the smallest uncertainty belong to Class 00, followed by 0.5, 1, and finally 2.}

The C15 is available for applications that require compressive forces only. It complies with the requirements of Class 00 per ISO 376. Both C15 and U15 provide an unusually high output signal. With more than 4 mV/V, the input levels of the amplifier modules can be fully utilized, resulting in excellent resolution.

Torque Reference Transducers

For the torque range, the TB2 is recommended as a reference transducer. Owing to an optimized design, the measuring body made of one piece in the form of a closed, hollow body, the measuring system is protected against environmental influences such as moisture. Because of this, and the IP67 degree of protection, the sensors are ideally suited for calibrations in industrial environments. Excellent performance can be achieved in combination with a suitable precision measuring instrument. For the range from 10 to 100 % of the rated torque, the highest class, 0.05, as per DIN 51309 is achieved.

Provided that a DAkkS calibration is performed, modern factory standards ensure traceability to the national standard. Assessing measurement uncertainty enables you to place the last piece of the puzzle. Along with the measurement uncertainty calculation, the reference sensor, and the calibration, the required traceability to the sensor on site is accomplished. HBM also helps you assess measurement uncertainty by offering seminars on ways to calculate the measurement uncertainty of force and torque measuring chains.