| 摘要 |
PURPOSE:To detect interlacing fault contacts with less number of tests in a high speed at any time in an arbitrary timing, by additionally providing a simple test circuit to an input circuit section and a function discriminating the result of test for a central processing unit. CONSTITUTION:Input line groups L00-L03 are selected by turning off photocouplers PHP, PHVT0-PHVT3 and PHS0 and turning on PHHT0 and PHS1 at first to monitor signals at terminals D0-D3 and similarly, the photocoupler PHS0 is turned on and the PHS1 is turned off to monitor the signal at the terminals D0-D3. The PHHT1 is turned on in place of the PHHT0 to select the PHS0 or PHS1, allowing to detect interlacing fault contacts only caused in the input line groups L10-L13 or said contacts among the groups. |
