SYSTEM FOR MAKING POLLING EFFICIENT FOR MONITOR BASED ON DETECTION OF CHANGE IN EARTHING INFORMATION

摘要

PURPOSE: To obtain the efficient system of polling by a monitored device based on detection of an earthing information signal in which polling is made efficient by receiving a polling timing of a monitor monitoring a state of plural monitored devices as earthing information from the monitored device. ;CONSTITUTION: Monitored devices 2₁-2_n output an output 200₁ at a high level for a time (t) representing an information change in the devices to a monitor 1 via a transistor(TR) as earthing information. The monitor 1 receives the earthing information at its Schmitt trigger IC via a photocoupler PC to generate an input 200₂ to the monitor. The monitor 1 detects the information change in the monitored devices 2₁-2_n by monitoring the state of the input 200₂ to the monitor and polls the information of the monitored devices 2₁-2_n when the monitor 1 detects it that the input 200₂ of the monitor side reaches a high level for a time t-sec.;COPYRIGHT: (C)1994,JPO&Japio