Calibration software for controlling process calibrators. Calibration software for the GOSSEN METRAWATT process calibrators METRACAL MC, METRAHIT CAL, METRAHIT 28C, METRAHIT 28C light and METRAHit 18C. With METRAwin 90-2 and an interface adapter, the handheld calibrator with the multimeter becomes a professional PC-based calibration system for measuring transducers, display and recording devices, etc. The calibration procedures are created using METRAwin. The analog preset values are transferred from the PC to the calibrator using an IR adapter and fed into the calibration object from its analog output. The analog output value of the calibration object is finally measured by the multimeter and fed back to the PC for evaluation via the interface. If the measurement result is within the specified tolerances, the next calibration step is automatically generated until the entire procedure has been processed. The calibration data can be transferred to other Windows applications on the PC (e.g. Word, Excel). The software works under the graphical user interface 'Microsoft Windows®'.