Delta-T Devices AP4, User Manual

Page: 47 / 64

Layout and Control
Page 47
Layout and Control
Examine the head unit. It is like a large clothes peg, for clipping onto leaves. Identify the
shiny mirrored surface of the RH sensor inside the cup. It is quite fragile and is also easily
damaged by organic solvents. Next to it is a microchip thermistor, no bigger than a pin
head. Opposite the cup a second microchip thermistor is buried in the translucent
flexible silicon rubber pad. These measure the cup and leaf temperatures respectively.
One control button is mounted
next to the light sensor.
The cable attached to the head
contains a tube for air as well as
signal wires.
The tubing plugs into a container
of self-indicating desiccant,
located in the pocket to the left of
the keyboard. Check the
desiccant is dry
– see page 46.
The cable plugs into the head
socket on the left of the
keyboard.