Raymarine AUTOHELM ST50 PLUS DEPTH Operation And Installation page 13

Certain atmospheric conditions may cause condensation to form on the
control head window. This will not harm the unit and can be cleared by
increasing the illumination setting to Level 3.
Chemical and abrasive materials must not be used to clean the control head;
if it is dirty, clean with a soft, damp cloth.
Transducer
Refer to the Installation and Maintenance instructionssupplied with the
transducer.
Cabling
Examine all cables for chafing or damage to the outer shield and, where
necessary, replace and resecure.
For advice, or further information regarding the instajlation of this product,
please contact the Autohelm product Support Department or your own
National Distributor.
Chapter 4: Operation
As it leaves the factory the ST50 Plus Depth is set with:
'depth units in feet

transducer off set set to 0 feet

shallow alarm set to 10 feet

deep alarm set to 100 feet

low anchor alarm set to 50 feet

high anchor alarm set to 50 feet

These settings can be changed in calibration, Chapter 6.
When the unit is poweredup for the first time water depth will be displayed.
Note:
that the display 'is not being updated and that the currently cfrspkryedvalue
was the last valid echo.