Automated multichannel sensor compensation and calibration

Delphin Technology AG: Many of today's measurement requirements involve large numbers of measurement channels and sensors. Set-up and preparation times for large-scale measurement and testing procedures are not insignificant. Measurement results must be traceable so the calibration of each sensor needs to be known and taken into account when analysing data.

To significantly reduce the effort required here, Delphin Technology has extended its ProfiSignal software with functions to enable users to automate calibration and sensor compensation.

Automated calibration using ProfiSignal

ProfiSignal gives users direct control over calibration and adjustment via multichannel trends. Complete applications for calibration can also be generated. All the functions for automating calibration are then available. Links to sensor databases are possible via SQL, ASCII or dll interfaces. The management of calibration chambers via an interface is also easy to implement. An integrated report generator produces calibration protocols – also in PDF format – at the click of a button.

Typical applications for sensor compensation and calibration

• Temperature distribution measurement for ovens and hobs
• Determining characteristic curves for electrical potentials
• Electrode taring to analyse corrosion on ship hulls
• Calibration of process furnaces and thermocouples according to CQI9
• Measuring temperature uniformity
• Determining the efficiency of heating systems
• Thermal analysis of wood-fired furnaces

Measuring temperatures in heat exchangers

An example is given here of the high-precision measurement of temperatures on heat exchangers. To achieve reliable values, the RTDs or thermocouples being used must provide precise measurements. Any sensor produces deviations so that an easy method of compensation is required. The sensors are therefore placed in an homogeneous temperature block, e.g. an oil bath or calibration chamber. Following a saturation period, reference values are then used to automatically determine deviations. Compensation values are then recorded in the compensation field of each sensor. This takes places as offset correction (1 step), slope adjustment (2 steps), or multipoint calibration (up to 100 steps). The actual measuring procedure then uses the sensor-compensated values – post-processing of the measurement data is therefore not required.