| 摘要 |
PURPOSE:To improve the safety of a system using a logic by taking a input value which fixes the output states of input gates of inputs used for the other purposes to the logic, where the final output of a logic circuit certainly goes to the non-operating state, at the time when a purpose select input is changed to the select state of another purpose by the occurrence of malfunction. CONSTITUTION:The input value is so specified and fixed that unused inputs keep the high level independently of outputs at the time of normalcy and the control output is changed to the low level to prevent the uncontrollable state at the time of indication error for the occurrence of trouble, thereby preventing the system from getting uncontrollable to improve the safety. A part of this logic can be constituted by software; and in this case, merits on production are acquired because individual setting of unused inputs is unnecessary and they can be set as internal data. When the logic is constituted by software, this control logic can be built in the input part of a controller. |
