Apparatus for use in controlling the operation of a hydrocarbon production well comprises: supply means (1) for providing an electric power supply; a plurality of electrically operated actuating devices (M1 --- M10); drive means (8) responsive to the power supply for providing a drive signal for the devices; and control means (3, 5, 8, 12, 14, 16 --- 32) for applying the drive signal to the actuating devices in a multiplexed manner.
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