Raymarine Autohelm 100, Install Manual

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44 TYPE 100/300 Operation and Installation Handbook
Plumbing
If the autopilot operated hydraulic cylinder is independent of the manual
steering system, a solenoid operated bypass valve
(Z079 (12V),Z122 (24V)) should be fitted to allow the cylinder to backdrive
when manual steering. The bypass valve should be connected to the
‘bypass’ connector on the Type CR Interface Unit.
The bypass valve should be mounted between the autopilot steering
cylinder ports and, under normal circumstances, be de-energised to allow
the cylinder to backdrive. When the autopilot is engaged, the valve is
energised by the Type CR Interface to allow the autopilot steering cylinder
to drive the rudder.
Hydraulic cylinder
Bypass valve
Autopilot
hydraulic
drive
Manual steering system Cable to course computer 'Bypass' connector
D766-1
Note: The bypass valve voltage must be matched to the course computer
supply voltage, i.e. 12V or 24V.
If the steering cylinder is unbalanced (single ended), a pilot operated
pressure relief valve must be connected (as shown) to enable excess oil to
be returned to the reservoir when the cylinder ram is retracting.