| 摘要 |
PURPOSE:To surely detect fault or abnormality regardless of the magnitude of AC input and also improve the accuracy in monitoring and the reliability by inputting a signal for monitoring the operation of an analog input part into an analog filter through a signal transmitting means and monitoring it. CONSTITUTION:An analog input part 3 is provided with a monitoring signal generating circuit 3D. For the monitoring signal S, harmonics synchronized with the frequency of the system is used, so a monitoring signal S is created by taking the sampling signal Ps from the CPU on a mother board into the monitoring signal generating circuit 3D, and diving it. The monitoring signal S created this way is sent to an input transformer 2 through a connector 6b, a cable 5, and a connector 6a, and is turned back to the input transformer 2, and again it is input into the analog filters 3A and 3B of an analog input part 3 through the connector 6a, the cable 5, and the connector 6b. Hereupon, the cable 5 and the connectors 6a and 6b constitute a signal transmitting means. |
