I/O INTERFACE DEVICE, CONTROL METHOD AND CONTROL SYSTEM

PROBLEM TO BE SOLVED: To provide an I/O interface device, a control method and a control system that normally switch an operation state even if having failed to receive a signal to switch the operation state from an active state to a standby state. SOLUTION: The I/O interface device 300a includes a means 32a for receiving a result of operation from a control device 200a, a means 33a for generating information indicating an active or standby operation state of the device, a means 31a for outputting the received result of operation if the generated information indicates an active state, a timer 35a for repeatedly measuring time, a counter 36a for counting the number of times that the timer 35a has measured a predetermined time, and a means 37a for causing the generation means 33a to generate information indicating a standby operation state of the device if the count by the counter 36a is larger than a threshold. COPYRIGHT: (C)2011,JPO&INPIT