VAF instruments OILCON MARK 6M - Electro Pneumatic Unit (EPU); Intrinsically Safe Signal Cable; Starter Box

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2.2.2 Electro Pneumatic Unit (EPU)
Reference drawings
 Dimensional drawing and parts list EPU 1-2 sample valves Mark 6M 0806-1287
The Electro Pneumatic Unit (EPU) contains the control electronics and the solenoid valves to switch
the pneumatic signals. It also contains the Zener barriers for the input signals from the flowmeter(s),
skid flow meter and measurement cell. There is a single electronic card installed, and a power
supply in the cover of the upper section of the cabinet.
The EPU is designed for mounting in the engine room opposite the Skid on the engine room/pump
room bulkhead or in another suitable location.
2.2.2.1 Intrinsically safe signal cable
The engine room mounted EPU is connected to the pump room mounted detector cell located within
the skid assembly via an intrinsically safe (I/S) signal cable. The cable carries the following signals
from the skid:
 Oil content signals generated by the detector cell
 Flow rate of sample water through the skid
 LED feedback signal
2.2.2.2 Starter box
Reference drawings
 Dimensional drawing motor starter box Ballast Monitor Mark 6 0806-1075
The control of the sample pump motor is from the EPU via the starter box. This unit contains a relay
to switch the 3-phase supply to the pump motor and a thermal trip to protect the pump motor. It also
has a main switch to isolate the pump motor from the 3-phase supply in case of maintenance.
Location for the starter box is the engine room in the proximity of the sample pump motor.