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Verfügbare Sprachen
Verfügbare Sprachen
2. Indoor
/ Outdoor
Interface Circuit
@ The interface circuit superimposes an interface signal on the 35V DC line supplied from the outdoor unit to
perform communications between indoor and outdoor units.
This circuit consists of a transmiting circuit which
superimposes an interface signal transmit from the micro computer on the 35V DC line and a transmiting
circuit which detects the interface signal on the 35V DC line and outputs it to the micro computer.
@ Communications
are performed by mutually transmiting and receiving the 4-frame outdoor request signal one
frame of which consists of a leader of approx.
100 ms., start bit, 8-bit data and stop bit and the command
signal with the same format transmit from the indoor unit.
@ The request signal (SDO), output from pins @ and @ of the outdoor microcomputer, is input to pin @ of
IF-HIC. IF-HIC creates a high-frequency signal from an approx. 38kHz signal generated by an oscillator: circuit
using a comparator, and outputs an intermittent signal corresponding to the request signal, via pin @.
The signal at pin @ is superimposed
on the DC 35V line through the IF transformer and is supplied to the
indoor unit.
@ The indoor interface circuit has the same basic configuration as that of the outdoor unit. It uses C801
to
eliminate DC components from the request signal supplied from the outdoor unit, and then supplies the signal
to pin
of IF-HIC. IF-HIC uses a comparator to convert the approx. 38kHz harmonic signal at pin (8) to
digital signals (approx. 5V, OV) which can be recognized by a microcomputer,
and then supplies them to
pin
(9 of the indoor microcomputer.
@ The indoor unit is interfaced. with the outdoor unit in the same way. The operation command
(SDO) from
the indoor microcomputer is input to IF-HIC via pin (3), and the approx. 38kHz harmonic signal is
superimposed
on the DC 35V line in the same way as with the outdoor unit and is supplied to the outdoor
unit.
@ The outdoor unit receives the signal at pin
of IF-HIC through the IF transformer and converts
it to digital
signals (approx. 5V, OV) which are supplied to pins @) and @ (SDI) of the microcomputer.
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