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: An electronics module for use subsea is provided. The electronics module comprises a vibration sensor on a printed circuit board in the electronics module. the vibration sensor being configured to sense vibration of the electronics module. The module is typically a subsea electronics module for use in a control system for a subsea hydrocarbon extraction well facility.

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 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 method of enabling the cooling of components of an electronic unit is provided. The method comprises providing a thermally conductive liquid or gel in contact with the components wherein the unit is an electronic module comprising a casing comprising metallic material and housing the components. The method further comprises including such liquid or gel in the casing to fill the entire space within the casing apart from the components so that heat from the components can be conducted via the liquid or gel to the casing.

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 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.