Method and apparatus for controlling a downhole tool

A downhole processing apparatus (44) for controlling a downhole tool (100) in a well is disclosed and comprises a downhole processing device (202) providing a first timing operation (TIMER 1; 302) and a second timing operation (TIMER 2; 304); the first timing operation (TIMER 1; 302) being associated with a first downhole sensor (60) capable of at least receiving a signal sent via a first transmission mechanism; the second timing operation (TIMER 2; 304) being associated with a second downhole sensor (210) capable of at least receiving a signal sent via a second transmission mechanism; a data storage device capable of storing data received from the first (60) and second (210) downhole sensors; and the downhole processing device (202) being adapted to be triggered by the first (TIMER 1; 302) and second (TIMER 2; 304) timing operations to check the data storage device, at least once during the respective first (TIMER 1; 302) and second (TIMER 2; 304) timing operations, for data received from the first (60) and/or second (210) downhole sensors and the downhole processing device (202) being adapted to act upon that data to control the downhole tool (100) if instructed to do so.