Hitachi RAC-25WEB - Page 46

Approx. 420 s.
5V
[Typical communication waveform]
Approx. 400 ms.
Enlarged reception waveform
Fig. 5-2
An infrared signal from the remote control unit is converted to an electrical signal by the remote
control light-receiving unit (IC821) and is received by the microcomputer. Data is transmitted as
digital data 0 and 1 by changing the interval of the basic pulses at about 420
s.
Remote control reception input
(pin of microcomputer)
Beep (reception tone)
INPUT
+
GND
66
s7HENTHEBUZZERSOUNDSANAPPROX
K(ZSQUARESIGNALISOUTPUTFROM
BUZZEROUTPUTPINOFTHEMICRO
computer. After the amplitude of this
signal has been set to 12Vp-p by a
transistorITISAPPLIEDTOTHEBUZZEr.
4HEPIEZOELECTRICELEMENTINTHEBUZZER
OSCILLATESTOGENERATETHEBUZZERgSSOUND
R640
C632
The indoor fan motor and drive circuit are connected to the primary power supply. They therefore have voltage to ground.
Guard against electric shocks.
7HILETHEPRODUCTISENERGIZEDDONOTUNDERAny circumstances detach or reattach a connector. Any such practice would
cause a high voltage to rUNRESULTINGINTHEINDOORfan motor and board circuit being destroyed. (Check the discharge of
the C003 before detaching or reattaching the connectors.)
Caution
Caution
5
66
46