| 摘要 |
PROBLEM TO BE SOLVED: To provide a numerical control system capable of resetting an internal register of an I/O unit without the need to turn on or off a power supply of the I/O unit, and provided with an internal-register self-reset function by serial communication signal monitoring.SOLUTION: A serial-communication-signal monitoring circuit is provided within an I/O unit, so that data and an idle signal, that is, a serial communication signal is monitored. If a state where the serial communication signal has been in a high or low state for predetermined time or longer is detected, then it is considered that the serial communication signal is broken, a reset pulse signal is generated, and an internal register of the I/O unit is reset. Owing to this, it is unnecessary to turn on or off a power supply of the I/O unit when a power supply of a numerical control device is turned on or off.SELECTED DRAWING: Figure 7 |
