JPS57702A - Water level controller - Google Patents

Abstract

PURPOSE:To improve the reliability of a final output signal by operating indepen- dently a processor and a comparator which receive the same input, by comparing their outputs with each other, and then by obtaining the final output only when the coincidence between the both is obtained. CONSTITUTION:A set water level signal 1a setting the down flow of a gate which regulates a water level, a measured water level signal 1b for the water level, and an opening signal 1c for the gate are inputted to a processor 2 via an input device 1. This processor 2 inputs the signals 2a and 2b to the AND gates 3-1 and 3-2 of a coincidence circuit 3. A comparator 4, on the other hand, inputs the signals 1a and 1b and outputs a gate opening signal 4a when the signal 1b is greater than the signal 1a or a closure signal 4b when less. Then, the signal 4a is checked by the gate 3-1 as to coincidence with the signal 2a and when so, a gate opening signal 3a is outputted. Similarly, when the coincidence with the closure signal 4b is found, a gate closure signal 3b is outputted. Consequently, a final signal is obtained only when the outputs of the processor 2 and comparator 4 coincide with each other.