Incremental counter for lengths or angles - has reference mark and two=way counter for easy check of measurement and automatically stops on receiving reference pulse

摘要

An incremental measuring system is used for lengths or angles. It uses a fixed reference mark whose absolute position is known, and an electronic two-way counter for the counting of forwards or reverse increments, permitting an observer to make an easy check of the accuracy of a result of measurement. The counter automatically stops on receiving a reference pulse from the reference mark, and a required value can then be set manually or automatically. A check is made by running as far as the reference mark and checking that the required value is shown.