| 摘要 |
PURPOSE:To excute self-diagnosis without inviting a rise of a system cost by using a digital input circuit for both an original input action and a read-back action. CONSTITUTION:The data sent from a bus 5 of a computer are stored at flip- flops 6-1-6-n and loads 3-1-3-n are driven through output transistors 7-1-7-n. An answer-back of output transistors 7-1-7-n is executed by using photo- couplers 14-1-14-n and sent through diodes 11-1-11-n to gate circuits 16-1-16-n and sent to the bus 5 of a computer. When the computer reads an answer-back signal, a transistor 9 is turned off and a signal is sent through the diodes 11-1-11-n. On the other hand, a process output signal judges with comparators 8-1-8-n that a contact is on or off and a signal is sent through diodes 12-1-12-n to the gate circuits 16-1-16-n. |
