| 摘要 |
<p>PURPOSE:To automatically effect polarity correction even when there is any improper wiring in polarity of a two-wire communication line to which a variable air amount apparatus is connected. CONSTITUTION:A system controller and a variable air jut apparatus are constructed in the same manner, and include normal passages 81, 83 and polarity inversion passages 82, 84 which are switched respectively to a transmitter/ receiver part with a relay contact. They are connected with a communication line 24 mediating a communication IC 46 via photocouplers 45, 47. A normal signal is transmitted from a controller, and when communication is impossible, the operation is switched for retransmission. When the communication holds, an instruction is transmitted and the side of the variable air amount apparatus is forced to be switched to the polarity inversion path and a controller side is returned to the normal path. Hereby, for the variable air nut apparatus where polarity is inverted owing to the mistaken wiring the communication signal is again inverted through the polarity inversion path for automatic polarity correction and is recognized as a normal communication signal so that an air conditioner can be constructed without high level expert knowledge and air conditioning operation is rapidly ensured after the construction.</p> |
