A travelling standard for the calibration of data-acquisition boards

The large use of measurement systems based on data-acquisition boards makes the traceability-chain assurance a tricky problem, due to the difficulty in consistently calibrating such boards. In this paper the authors describe a travelling standard, which can be used for the calibration of many commercially available acquisition boards. By employing such a travelling standard, the calibration procedure can be remotely exercised by a calibration laboratory through the PC which hosts the board that has to be calibrated. In such a way the calibration results refer to environmental, software and hardware conditions that exactly match the board operating-conditions. Furthermore, the board unavailability time is drastically reduced, with a consequent economic advantage for the board owner. The travelling standard embeds a micro-controller, which is responsible for the communication with the PC that hosts the board and for the board-stimulus generation, and a digital multimeter, which acts as a reference standard.