
– 88 –
9. Reset Circuit
●
Reset circuit performs initial setting of microcomputer program when power is turned on.
●
Microcomputer resets program with reset voltage set to Lo, to enable operation at Hi level.
●
Fig. 9-1 shows the reset circuit, and Fig. 9-2 shows waveforms at each point when power is turned on/
off.
●
After power is turned on, 12V line and 5V line voltages rise: When 12V line voltage reaches 7.2V (Zener
voltage of ZD201), ZD201 turns ON and Q208 and Q209 turn on, and reset voltage becomes Hi. Reset
voltage is not set to Hi until VDD of microcomputer rises to 5V, enabling operation, due to ZD201.
●
After power turns off, when 12V line voltage drops, ZD201 also turns OFF. However, Q208 is left ON since
reset voltage is fed back by R294, until 12V line drops to about 7.6V. This prevents chattering of reset
voltage due to voltage chnge in 12V line.
Micro
computer
AX-6M00
48
RES
Fig. 9-1
C224
R295
R294
R293
C222
C223
R290
R292
ZD201
0V
0V
12V
Q208
R291
Q209
+5V
0V
0V
12V line
12V line
5V line
5V line
Fig. 9-2
Reset voltage
Reset voltage
12
6
0
V
oltage when power is turned ON
V
oltage when power is turned OFF
12
6
0
Time
Time
Содержание RAM-50CNHZ2
Страница 41: ... 40 WIRING DIAGRAM MODEL RAM 50CNHZ2 OUTDOOR UNIT ...
Страница 47: ... 51 BASIC MODE MODEL RAM 50CNHZ2 ...
Страница 50: ... 57 ...
Страница 51: ... 59 ...
Страница 102: ... 110 PARTS LIST AND DIAGRAM MODEL RAS 20CNHZ2 11 2 18 8 20 12 63 1 4 60 3 7 14 15 6 5 16 13 88 61 17 9 62 10 ...
Страница 104: ... 112 MODEL RAS 30CNHZ2 8 12 23 1 3 5 60 14 4 7 6 13 61 61 11 62 35 12 10 9 17 2 63 18 19 15 16 ...