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6-6. Electric expansion valve control circuit
Main P.W.B.
６
５
４
３
Electric
２
expansion
１
valve
＋
Ｃ ４ ０ １
Ｃ Ｎ １ ５
WHT
ＸＡ− ６ Ｐ
Electric expansion valve is driven by B-12V. Opening of the valve is controlled by feeding power to 1
●
or 2 phases of the 4-phase coil to switch the polarity of the coil.
The relation between the conducting phase switching direction and open/close direction is as shown
●
below. When the power is turned on, approx. 0.9 V is applied to CN15 pins 1 to 4 ; when no power
is supplied, approx. 12 V is applied. When the power is reset, expansion valve performs initial
operation for 5 to 10 seconds.During initial operation, measure pins 1 to 4 of CN15 using
multimeter: If no change is found around 0.9 V or 12V, expansion valve or microcomputer is
defective.
Fig. 6-15 shows logic waveform during the operation of expansion valve.
●
Co n n e c t o r
P i n No .
Ｂ − １ ２ Ｖ
Ｒ ４ ０ ４
８
１ ５
１ ４
２
３
１ ０ ０
１ １
６
７
９
４
５
１ ２
１ ３
Ⅰ Ｃ ６
Ｂ − ０ Ｖ
CN 15
Lead
Pin No.
wire
1
O N
White
④
O F F
Yellow
③
O F F
Orange
②
O F F
Blue
①
O p e r at i o n m o d e
1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 VA LV E C LO S E
8 → 7 → 6 → 5 → 4 → 3 → 2 → 1 VA LV E O P EN
④
③
②
①
50m s .
＋ ５ Ｖ
Ｒ ４ ０ ３
Ｒ ４ ０ ７
４
１
Ｐ Ｑ ４ ０ １
２
３
Ｒ ４ ０ ８
Ｐ Ｑ ４ ０ ２
Ｒ ４ ０ ９
Ｐ Ｑ ４ ０ ３
Ｒ ４ １ ０
Ｐ Ｑ ４ ０ ４
Fig. 6-14
Table 6-4
Drive status
2
3
4
5
O N
O FF
O FF
OFF
O N
ON
O N
O FF
O F F
O FF
O N
ON
O F F
OF F
O FF
O FF
7 5 m s .
2 0 0 m s .
Fig. 6-15
- 64 -
H Ⅰ C
Ｑ ４ ０ １
1 6
Ｑ ４ ０ ２
1 5
Ｑ ４ ０ ３
Ｒ ２ ２ ９ ９ ３
Ｒ ２ ９ ４
Ｑ ４ ０ ４
1 4
Ｒ ２ ９ ５
1 3
Ｒ ２ ９ ６
6
7
8
O FF
O FF
O N
OFF
O FF
OFF
O N
O FF
O FF
O N
O N
ON
1 2 V
0 . 9 V
Microcomputer
５ ８ ８
Valve 4
５ ７
Valve 3
５ ６
Valve 2
５ ５ ５
Valve 1
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