Abstract: A method of testing a solenoid of a directional control valve in a subsea hydrocarbon production system, the solenoid having a coil and an armature for operating the valve and the coil being energized by a drive voltage across it, the method comprises removing or reducing the drive voltage and sensing current through the coil to produce an indication of movement of the armature.

Abstract: A heat sink mounting apparatus including: a heat sink; and a device housing, the housing having a slot in the wall of the housing configured to receive a heat sink, wherein the heat sink and the housing are configured such that the heat sink can be secured within the slot with an interference fit.

Abstract: A method of testing a control system including a valve which is operable by a solenoid is disclosed. The method comprises applying a current through a coil of the solenoid, the current being insufficient to cause the solenoid to operate the valve, and monitoring a response of the system to the current.

Abstract: A method of energizing a coil of a solenoid of a directional control valve, wherein an armature of the solenoid moves between a first position in which the solenoid is operating and a second position in which the solenoid is not operating, the method comprising energizing the coil with a voltage, controlling the voltage, detecting a current in the coil at which the armature of the solenoid moves between the first position and the second position, and using the current at which the armature of the solenoid moves between the first position and the second position increased by a margin as an operating current for energizing the coil of the solenoid.

Abstract: A heat sink mounting apparatus including: a heat sink; and a device housing, the housing having a slot in the wall of the housing configured to receive a heat sink, wherein the heat sink and the housing are configured such that the heat sink can be secured within the slot with an interference fit.

Abstract: A method of determining the location of a fault in a cable at an underwater fluid extraction facility is provided. The method comprises: providing a time domain reflectometry unit at the facility, the unit being connected to at least one wire within the cable; causing the unit to transmit a current pulse to the wire; detecting a reflected pulse received at the unit; determining the time duration between the pulse transmission and the reflected pulse reception and using the duration to calculate a distance between the fault and the unit; and determining the location of a fault on the wire using the calculated distance.

Abstract: A method of testing a solenoid of a directional control valve in a subsea hydrocarbon production system, the solenoid having a coil and an armature for operating the valve and the coil being energized by a drive voltage across it, the method comprises removing or reducing the drive voltage and sensing current through the coil to produce an indication of movement of the armature.

Abstract: A method of determining the location of a fault in a cable at an underwater fluid extraction facility is provided. The method comprises: providing a time domain reflectometry unit at the facility, the unit being connected to at least one wire within the cable; causing the unit to transmit a current pulse to the wire; detecting a reflected pulse received at the unit; determining the time duration between the pulse transmission and the reflected pulse reception and using the duration to calculate a distance between the fault and the unit; and determining the location of a fault on the wire using the calculated distance.