This document establishes a procedure to calibrate 1D displacement transducers with nearly linear transfer functions. This procedure is tailored to the needs of sensors used in crash tests. The calibration is carried out with the sensor disassembled from the dummy or test system. The procedure is valid for sensors with analogue as well as digital output.st edition 2021-07 Road vehicles — Calibration procedure for displacement devices Véhicules routiers — Procédés de calibration pour les dispositifs de déplacement Reference number ISO/TS 23521:2021(E) ？ ISO 2021 ISO/TS 23521:2021(E) COPYRIGHT PROTECTED DOCUMENT ？ ISO 2021 All rights reserved. Unless otherwise specified, or required in the context of i