Hitachi RAF-25FX8 Mode D'emploi page 76

3. Room Temperature Thermistor Circuit
A room temperature thermistor circuit is shown in Fig. 3-1.
According to room temperature, the voltage of point
5V
Room Temperature
Thermistor
R305
R301
◯ A
Fig. 3-1
4. Heat Exchanger Thermistor Circuit
Heat exchanger temperature is noticed inside the room
(1) Preheating
(2) Low-temperature defrosts at cooling･dehumidification operation time.
(3) Not working of reversing valve or detection of opening of heat exchange thermistor is controlled.
According to heat exchange temperature, the voltage of point
5V
Heat exchanger
thermistor
R306
R302
◯ A
0V
Fig. 4-1
5. Humidity Sensor Circuit
5V
1
2
3
Humidity sensor
0V
4.0
3.5
3.0
2.5
2.0
1.5
1.0
40
20 60
Humidity (
Fig. 5-2
Microcomputer
Room
64
temperature input
C302
Microcomputer
Heat exchanger
63
input
C303
0V
R308
＋
R304 C301
−
0V 0V 0V
Fig. 5-1
From the output (② pin) of humidity sensor, the 5V pulse of different width is
output according to detected humidity. Smooth output pulse is carried out by
25℃
C301 and it changes into the characteristic of voltage-humidity as shown in
Fig.5-2. The micro computer detects and controls humidity by reading this
voltage directly.
80
)
％
becomes as it is shown in Fig.3-2.
becomes as it is shown in Fig. 4-2.
5
4
3
2
1
0
Microcomputer
Humidity
62
C305
– 94 –
5
4
3
2
1
0
0 10
Room temperature
Fig. 3-2
0
-10 10
20
Room temperature (
Fig. 4-2
20 30 40
(℃)
30 40
)
℃