| 摘要 |
<p>PURPOSE:To enable the number of output terminals of a microcomputer to be reduced and further to facilitate diagnosing of trouble condition of a printed circuit board at a site by a method wherein a light emitting diode is connected in parallel with an electromagnetic coil of a DC relay in an electric power supplying circuit for a compressor and a blower or the like and means for selecting a turning-on/off and flickering of the light emitting diode is provided and then an abnormal information of the printed circuit board during a diagnosing of trouble condition is displayed. CONSTITUTION:In order to set a printed circuit board to a check mode, a switch 11 is closed. A microcomputer 1 runs a series of check modes with a program stored in the microcomputer 1, outputs its result with a dynamic output to outputs O1 and O2 to light a light emitting diode and it can be judged that a circuit at the outputs of O1 and O2 is normal. If a turned-on or turned-off condition of each of the switches 11-13 is displayed under a combination of a lighted condition, a flickering condition and a turned-off condition of each of the light emitting diodes 2 and 3, eight patterns can be discriminated with two light emitting diodes, thereby it is possible to judge if an input circuit in the printed circuit board is good or not.</p> |
