Library apparatus having a motor driving control including abnormal motor and excess current detecting circuits

• US 5,982,120 A
• Filed: 05/12/1997
• Issued: 11/09/1999
• Est. Priority Date: 05/12/1992
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Sakaguchi, Masahiko, Miyaguchi, Ryuuichi, Ono, Hitomi, Ohmido, Tatsuya, Akiyama, Yoshiki, Inazawa, Katsumi
• Primary Examiner(s): MARTIN, DAVID S
• Application Number:
  US08/854,501
• Time in Patent Office: 911 Days
• Field of Search: 361/45, 361/87, 361/93, 361/23, 361/31, 361/33, 361/44, 361/71, 361/75, 361/72, 318/434, 318/798, 318/806, 318/805, 318/803, 318/802, 318/478, 388/811-824, 388/903
• US Class Current: 318/434
• CPC Class Codes: G06F 11/1441 Resetting or repowering
• CPC Class Codes: G06F 11/3037 where the computing system component is a memory, e.g. virtual memory, cache accessing, addressing or allocating within memory systems or architectures G06F12/00; checking stores for correct operation G11C29/00
• CPC Class Codes: G06F 11/3058 Monitoring arrangements for monitoring environmental properties or parameters of the computing system or of the computing system component, e.g. monitoring of power, currents, temperature, humidity, position, vibrations thermal management in cooling arrangements of a computing system G06F1/206
• CPC Class Codes: G11B 15/026 by using processor, e.g. microcomputer
• CPC Class Codes: G11B 15/68 Automatic cassette changing arrangements; automatic tape changing arrangements
• CPC Class Codes: G11B 15/688 the cassettes being transferred to a fixed recorder or player using a moving carriage
• CPC Class Codes: G11B 17/22 from random access magazine of disc records
• CPC Class Codes: G11B 17/228 Control systems for magazines G11B17/225 takes precedence
• CPC Class Codes: G11B 19/02 Control of operating function, e.g. switching from recording to reproducing
• CPC Class Codes: G11B 2220/41 Flat as opposed to hierarchical combination, e.g. library of tapes or discs, CD changer, or groups of record carriers that together store one title
• CPC Class Codes: G11B 27/002 Programmed access in sequence to a plurality of record carriers or indexed parts, e.g. tracks, thereof, e.g. for editing; transfer of record carriers from magazine G11B15/68, G11B17/10; G11B17/22
• CPC Class Codes: G11B 27/36 Monitoring, i.e. supervising the progress of recording or reproducing for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06
• CPC Class Codes: H02H 7/0838 with H-bridge circuit
• CPC Class Codes: Y10S 388/903 Protective, e.g. voltage or current limit

Abstract

A library apparatus having a motor driving control circuit including a processor, a motor driver circuit, a relay, a motor abnormal condition detection circuit, a current control circuit, an excess current detection circuit, and an abnormal current monitor circuit. The motor abnormal condition detection circuit is connected to the motor driver circuit, and detects an abnormal condition of at least one of the motor and the motor driver circuit. Upon detecting an abnormal condition, the motor abnormal condition detection circuit outputs a motor abnormal condition detection signal which prompts the current control circuit to regulate the current flowing through the motor driver circuit. If the current control circuit is unsuccessful, the excess current detection circuit outputs an excess current detection signal which triggers the relay to close the power source circuit of the motor driver circuit.

Claims

1. A library apparatus having a motor driving control circuit, said motor driving control circuit comprising:

a processor for executing various controls for driving of a motor;

a motor driver circuit for receiving a supply of power from a DC power source and driving said motor in response to an instruction of said processor;

a relay for opening or closing a power source circuit of said motor driver circuit;

a motor abnormal condition detection circuit connected to said motor driver circuit for detecting an abnormal condition of at least one of said motor and said motor driver circuit and outputting a motor abnormal condition detection signal;

a current control circuit including a current limiting resistor connected between said relay and said motor driver circuit, said current limiting resistor being used to control the current to flow through said motor driver circuit in response to the motor abnormal condition detection signal;

an excess current detection circuit connected to said current control circuit for detecting that the current flowing through said motor driver circuit is increased to an excess current and outputting an excess current detection signal; and

an abnormal current monitor circuit for monitoring the motor abnormal condition detection signal, the excess current detection signal and a control signal from said processor, and controlling control the opening/closing operation of said relay.

2. A library apparatus according to claim 1, wherein said motor driver circuit includes a motor abnormal condition detecting resistor connected in parallel to said motor, and said motor abnormal condition detection circuit includes conversion means for converting a voltage produced with said motor abnormal condition detecting resistor into another corresponding voltage value, and comparison means for comparing the voltage obtained from said conversion means with a preset reference value and outputting the motor abnormal condition detection signal.

3. A library apparatus according to claim 1, wherein said current control circuit includes a pair of switching elements which are connected in parallel to each other and controlled by the motor abnormal condition detection signal so that one of said switching elements presents an on-state while the other switching element presents an off-state, and said current control circuit further includes an excess current detecting resistor and a current controlling resistor connected in series to one of said switching elements, said current detecting resistor detecting an excess current which may flow through the circuitry, said current controlling resistor controlling the current to flow through said motor driver circuit.

4. A library apparatus circuit according to claim 1, wherein said current control circuit is changed over, when an abnormal condition of at least one of said motor and said motor driver circuit is detected by said motor abnormal condition detection circuit, into a current control mode without interrupting the current flowing through said motor driver circuit in response to the motor abnormal condition detection signal so that the current to flow through said motor driver circuit is attenuated.

5. A library apparatus according to claim 1, wherein said abnormal current monitor circuit turns off, when it detects the motor abnormal condition detection signal and the excess current detection signal at a time while said motor is being driven by said motor driver circuit, said relay to interrupt the current to flow through said motor driver circuit.