13
The sensor is mounted to the wall of the chamber using a ½”
NPT compression fitting installed in the chamber wall. Other
mounting configurations can also be used to meet the user’s
specific requirement. The Control Unit provides the
necessary indicators and controls to set the desired humidity
level and to measure the actual humidity level in the
chamber.
The front panel of the Control Unit shown in Figure 3.2-2
contains a 0.375”, 3½-digit LCD readout for both setting the
desired set point and for reading the relative humidity with a
resolution of ±0.1% R.H. A black, momentary RH LEVEL,
SET PT/READ switch selects the information to be
displayed. In the normal (Button out) position the readout
displays the measured relative humidity level. In the
depressed position, the readout displays the desired
humidity set point. When released, it automatically returns to
the READ position. A 10-turn screwdriver adjustable
potentiometer is used to adjust the set point from 0 to 100%
R.H.
Figure 3.2-2: Control Unit front panel
The Green DEHUMIDIFIER switch, when in the ON position
(in), places the system in the DEHUMIDIFY mode. When the
measured humidity is above the set point level, a control
signal activates the DEHUMIDIFY relay circuit and 115/230
VAC is applied to the DEHUMIDIFY AC outlet on the rear
panel. This turns on the Dehumidification System. When this
switch is in the OFF position (out) the Dehumidification
System will remain off irrespective of the RH level measured.
When this switch is in the OFF position, the Model 5112
operates as a precision electronic hygrometer.
