Title:
SEQUENCE CONTROLLER
Document Type and Number:
Japanese Patent JPS5719807
Kind Code:
A
Abstract:
PURPOSE:To check whether a sequence controller (SQCT) operates normally or not when it is started, by providing an FF showing a diagnostic mode when an electric power source is put to work, and a memory for storing a program for checking an operation. CONSTITUTION:When an elctric power source is turned on, an FF8 showing a diagnostic mode for checking an operation of an SQCT is set through an electric power source on signal line 13, and its diagnostic mode is indicated to a program counter 3 and an input/output control part 4 through a signal line 12. A counter 3 accesses only a memory 10 for storing a basic instruction of the SQCT which is a part of a user program area, and a diagnostic result. The control part 4 inhibits input/output of input/output information through a signal line 14. After the electric power source has been turned on, an operation control part 1 executes a diagnostic program stored in a memory area 9 at first, checks whether a basic instruction executed by the control part 1 is executed normally or not, and whether read and write of the memory 10 can be executed normally or not, shifts the basic instruction of the memory 9 to the memory 10, and checks the operation.
Inventors:
OKAMURA KOUSUKE
Application Number:
JP9276480A
Publication Date:
February 02, 1982
Filing Date:
July 09, 1980
Export Citation:
Assignee:
HITACHI LTD
International Classes:
G05B23/02; G05B19/042; (IPC1-7): G05B19/02