| 摘要 |
PURPOSE:To make a device small in size, to suppress a power consumption and to execute easily a backup by a battery at the time of a service interruption and also to decrease the number of component parts to improve the reliability of the device, by constituting so that counting of the number of input signals of a multi-channel is executed by a common counter. CONSTITUTION:When a data selector 11 selects a signal la of the first channel, an address corresponding to la is designated by an address bus 5, and a data of its designated address is set to programmable counters 2a-2c by preset signals 6a-6c. Since a programmable counter 2 is constituted by dividing it into three 2a-2c constituted of 8-bit, the preset signals 6a-6c are outputted successively. After this preset operation is ended, output signals 9a-9c of the counter are outputted, and an AND gate 12 is opened. In this case, if an input signal arrives already in the first channel, a read-out and write signal 8 of an RAM 3 is outputted by the AND gate. When a data of the previous time is set to the counters 2a-2c, a value counted up by ''+1'' to a counting value of the previous time is written in the RAM. |
