| 摘要 |
<p>PURPOSE:To detect the state of a monitoring state contact by interposing a digital input interface unit between an exclusive input/output unit and a monitoring contact and connecting the input/output unit to each digital input interface unit via a signal line and a common line used as a common lines respectively. CONSTITUTION:A program controller 2 is provided with an exclusive input unit 3 and an exclusive output unit 4. At a monitoring state contact 1, a signal line 5 is connected to an LED 9 together with a common line 6 connected to an address switch 8. At the same time, the contact 1 is connected to both units 3 and 4 via both lines 5 and 6 respectively. The switch 8 is set to each digital input interface unit 7. In such a constitution, the numbers of units 3 and 4 can be minimized and the input of the state signal of the contact 1 is attained with use of the units 7 in number equal to the contacts 1.</p> |
