Drive control circuit

• US 5,017,848 A
• Filed: 06/20/1990
• Issued: 05/21/1991
• Est. Priority Date: 07/10/1989
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Takahashi, Atsuhiko
• Primary Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US07/541,233
• Time in Patent Office: 335 Days
• Field of Search: 318/560-640, 371/2.1, 371/3, 371/5.1, 371/10.1, 371/14, 371/15.1, 371/19, 371/21.1, 371/40.1, 371/40.2, 380/4, 380/28, 380/46, 380/48
• US Class Current: 318/568.1
• CPC Class Codes: G05B 19/4063 Monitoring general control system G05B19/4062 takes precedence
• CPC Class Codes: G06F 11/004 Error avoidance G06F11/07 and subgroups take precedence
• CPC Class Codes: G06F 11/0796 Safety measures, i.e. ensuring safe condition in the event of error, e.g. for controlling element

Abstract

The present invention relates to a drive control circuit for controlling a driving system including, e.g., a carriage driving motor, a print head and others, which is to be employed in an apparatus such as a printer. More specifically, the present invention is concerned with a drive control circuit which can protect the driving system properly and prevent the driving system from being damaged, when a malfunction occurs in a ROM as in the case where the ROM in which a control program for controlling the driving system and a runaway detection program for the prevention of burning or the like which occurs in a driving motor as a result of the runaway of the control program have been written therein, is damaged or as in the case where no ROM is incorporated.

Claims

1. A drive control circuit of a type wherein at least one ROM in which a control program for controlling a driving system and a runaway detection program for the prevention of a malfunction which occurs in said driving system as a result of the runaway of said control program have been written therein is connected to a CPU which performs predetermined control of said driving system and when said control program is run out of control, said runaway detection program is executed to reset said CPU, thereby protecting said driving system, said circuit comprising:

protection means provided between said CPU and said driving system and for connecting said CPU to said driving system or disconnecting said CPU therefrom; and

ROM malfunction detecting means for detecting whether or not said ROM is in a normal operation state and for supplying a disconnection actuating signal to said protection means upon malfunction of said ROM.