Hitachi RAC-60DH7 - Initial Setting and Thermistor Circuits

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4. Room Temperature Thermistor Circuit
● Fig. 4-1 shows the room temperature
thermistor circuit.
5
4
3
2
1
0
010
Fig. 4-2
20 30 40
0V
Room
temperature
thermistor
0V
5V
L301
Fig. 4-1
62
A
R305
C302
Microcomputer
Room
temp. input
Voltage at
(V)
R301
A
● The voltage at depends on the room
temperature as shown in Fig. 5-2.
A
3. Initial Setting Circuit (IC401)
● When power is supplied, the microcomputer reads the data in IC401 (E
2
PROM) and sets the preheating
activation value and the rating and maximum speed of the compressor, etc. to their initial values.
● Data of self-diagnosis mode is stored in IC401; data will not be erased even when power is turned off.
Fig. 3-1
Microcomputer
External ROM
SCL
SDA
0V
0V
0V
5V
5V 5V
C401
IC401 (E
2
PROM)
R404 R403
27
26
1
2
3
4
8
7
6
5
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