Pressure signal for remote control of downhole tool

摘要

A remote control downhole valve (200) has a valve member (208), means (206) for moving the valve member (208), a pressure signal receiver (232) and control means (224) including a memory (228), and a signal comparing means, whereby a distorted form of a received first command signal can be compared with a distorted such signal in memory, and a second command signal can be verified.