JPH02250103A - Counter instruction executing system of programmable controller - Google Patents

Abstract

PURPOSE:To execute the processing at a high speed by generating each logical value data on an input signal of the previous time and an input signal of this time in the course of executing a counter instruction, writing this logical value data in a temporary storage circuit, and executing the counter instruction, based on a result of decision which is read out of a logic arithmetic circuit. CONSTITUTION:This system is provided with a ROM 2 in which a system program executed by a CPU 1 is stored, a RAM 3 of an input/output buffer memory, etc., an input circuit 4, an output circuit 5, and a stepping deciding circuit 6 for deciding the stepping of a counter CT. The stepping deciding circuit 6 is constituted of a temporary storage circuit 10 for storing temporarily logical values for showing logical states of an up-input and a down-input of this time and the previous time in count operation use clock input signals of the counter CT, and a stepping condition deciding circuit 11 for operating a stepping condition of the counter CT, based on this logical data and driving a result of decision as to whether the count operation is to be executed or not, etc. In such a way, the stepping condition of the counter in a counter processing instruction can be processed by a hardware, and also, the processing can be executed at a high speed by using a general purpose microcomputer.

Description

[Detailed description of the invention]

Claims (1)

[Claims] In a counter instruction execution method for a programmable controller that cyclically executes a predetermined program including a counter instruction, the logic value of the previous input signal among the input signals for counting operation of the counter and the current a temporary memory circuit that temporarily stores the logic value of the input signal; and in response to the output from the temporary memory circuit, the counter instruction is incremented based on the logic value of the previous input signal and the logic value of the current input signal. A logic operation circuit that performs logical operations on conditions to determine whether or not to perform a counting operation; and a logic operation circuit that generates each logical value data of the previous input signal and the current input signal during the execution of the counter instruction, and calculates the logical value A counter instruction execution method for a programmable controller, comprising: a processing circuit that writes data to a temporary storage circuit, reads a determination result from a logic operation circuit, and executes a counter instruction based on the determination result.