| 摘要 |
PURPOSE:To accurately diagnose a defect by providing an erroneous operation detector circuit, thereby detecting the malfunction of each drive circuit. CONSTITUTION:One terminals of resistors R1-R4 are connected to terminals 11a-11d in an erroneous operation detector circuit 6, and the resistors R1-R4 are respectively connected to load lines 4a-4d. The one terminals of the resistors R1, R3 and R2, R4 corresponding to the load lines becoming in reverse phase to each other are connected at the connecting points 12, 13. In such detector circuit 6, the voltages of the points 12, 13 are 1/2B at the normal time, voltage difference occurs between the points 12 and 13 at the abnormal time, and any of the first and second light emitting diodes LED1, LED2 is energized thereby, any of first and second phototransistors PTR1, PTR2 is conducted, thereby outputting detection signals at the terminals 17, 18. |
