US5410469A
Expired / Lapsed
US
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Diagnostic method for production line
Assignee: Mazda Motor Corp
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Filing: 1994-07-01
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Granted: 1995-04-25
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Expires: 2014-07-01
Abstract
Abstract A diagnostic method for a production line. The production line is in accordance with a ladder program, which is prepared on the basis of a map describing the operations of equipment composed of a plurality of drive devices. The method comprises the steps of: storing reference operation times necessary for executing the respective operations of the program elements of the ladder program; comparing the time it has actually taken a change to take place in the ON/OFF condition of each of confirmation devices for confirming the operations of the drive devices with the corresponding reference operation time; and locating, on the basis of the results of this comparison, any malfunctioning point of the production line.
Inventors
- 👤 Shunji Sakamoto
- 👤 Toshihiko Hoshino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:19
CPC Classifications
G; G05; G05B; G05B23/00; G05B23/02; G05B19/00; G05B19/02; G05B19/04; G05B19/05; G05B19/058; G05B2219/00; G05B2219/10; G05B2219/14; G05B2219/14057; G05B2219/14068
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
309 words
A diagnostic method for a production line including a plurality of drive devices in which the operation of one of said drive devices is represented by at least one operation step, the operation of the entire production line is represented by a plurality of operation blocks, each said operation block includes at least one of said operation steps, each said operation step includes a checking operation by a confirmation device for confirming the operation of the corresponding drive device, and each of said operation blocks operates independently of the other operation blocks from the start to end thereof, said method comprising the steps of: a: storing a map in a memory, each element of the map representing a correspondence between said drive and confirmation devices and warning devices corresponding to each said operation step; b: preparing and executing a sequence ladder program in which the following program elements are described in a form in which they are connected in parallel with each other in said sequence ladder program: b1: program elements describing an operation of one of said drive devices and its corresponding confirmation device in the equipment of the production line; b2: program elements each adapted to measure the period between the time said one drive device starts an operation and the time a drive device which is in the subsequent stage with respect to said one drive device starts an operation; and b3: program elements each adapted to set one of said warning devices in an operating condition when the measured time period is longer than a corresponding preset reference time; c: locating, when any one said warning device operates, a drive device corresponding to said any one warning device on the basis of the map; and d: judging the located drive device or the confirmation device associated with the located drive device as a faulty device.
Claim 2
Dependent Claim
309 words
A diagnostic method for a production line including a plurality of drive devices in which the operation of one of said drive devices is represented by at least one operation step, the operation of the entire production line is represented by a plurality of operation blocks, each said operation block includes at least one of said operation steps, each said operation step includes a checking operation by a confirmation device for confirming the operation of the corresponding drive device, and each of said operation blocks operates independently of the other operation blocks from the start to end thereof, said method comprising the steps of: a: storing a map in a memory, each element of the map representing a correspondence between said drive and confirmation devices and warning devices corresponding to each said operation step; b: preparing and executing a sequence ladder program in which the following program elements are described in a form in which they are connected in parallel with each other in said sequence ladder program: b1: program elements describing an operation of one of said drive devices and its corresponding confirmation device in the equipment of the production line; b2: program elements each adapted to measure the period between the time said one drive device starts an operation and the time a drive device which is in the subsequent stage with respect to said one drive device starts an operation; and b3: program elements each adapted to set one of said warning devices in an operating condition when the measured time period is longer than a corresponding preset reference time; c: locating, when any one said warning device operates, a drive device corresponding to said any one warning device on the basis of the map; and d: judging the located drive device or the confirmation device associated with the located drive device as a faulty device.
Claim 3
Dependent Claim
28 words
A method according to claim 1, wherein the confirmation device associated with the located drive device is judged to be faulty when it is in a non-operating condition.
Claim 4
Dependent Claim
33 words
A method according to claim 1, wherein when a reference operation time somewhat differs from the corresponding actual operation time, said reference operation time is corrected in accordance with the actual operation time.
Claim 5
Dependent Claim
37 words
A method according to claim 3, further comprising: calculating a standard deviation and a mean value of detected actual operation times; and correcting said reference operation time in accordance with the calculated standard deviation and mean value.
Claim 6
Dependent Claim
185 words
A diagnostic apparatus for diagnosing a production line controlled in accordance with a ladder program, including a plurality of program elements, and prepared on the basis of a map in which the operations of equipment comprised of a plurality of drive devices are described, said ladder program comprising a plurality of operation steps, each step including a drive device and confirmation device operated therein, said diagnostic apparatus comprising: memory means for storing in said map, reference operation times which are necessary for the execution of the program elements of said ladder program and which respectively correspond to the operations of the individual drive devices; register means for storing an identifier of a current operation step in said ladder program and an actual operation time required for a change to take place in the ON/OFF condition of a confirmation device of the current operation step; comparing means for comparing the actual operation time with the corresponding reference operation time as specified by the identifier; and locating means for locating, on the basis of a result from said comparing means, any malfunctioning step of said production line.
Claim 7
Dependent Claim
185 words
A diagnostic apparatus for diagnosing a production line controlled in accordance with a ladder program, including a plurality of program elements, and prepared on the basis of a map in which the operations of equipment comprised of a plurality of drive devices are described, said ladder program comprising a plurality of operation steps, each step including a drive device and confirmation device operated therein, said diagnostic apparatus comprising: memory means for storing in said map, reference operation times which are necessary for the execution of the program elements of said ladder program and which respectively correspond to the operations of the individual drive devices; register means for storing an identifier of a current operation step in said ladder program and an actual operation time required for a change to take place in the ON/OFF condition of a confirmation device of the current operation step; comparing means for comparing the actual operation time with the corresponding reference operation time as specified by the identifier; and locating means for locating, on the basis of a result from said comparing means, any malfunctioning step of said production line.
Claim 8
Dependent Claim
57 words
An apparatus according to claim 5, wherein said actual operation times and said reference operation times are stored in a single memory means, and wherein said actual operation times are updated and said actual operation times and said reference operation times are compared with each other each time the ON/OFF condition of a confirmation device is updated.
Claim 9
Dependent Claim
33 words
An apparatus according to claim 5, wherein when the reference operation time somewhat differs from the corresponding actual operation time, said reference operation time is corrected in accordance with the actual operation time.
Claim 10
Dependent Claim
37 words
A method according to claim 7, further comprising: calculating a standard deviation and a mean value of detected actual operation times; and correcting said reference operation time in accordance with the calculated standard deviation and mean value.
Claim 11
Dependent Claim
79 words
An apparatus according to claim 5, wherein said map is an operation step map including a drive condition for one of said drive devices, a condition for confirming the operation of said one drive device, said reference time, and said actual operation time, and said operation step map is prepared on the basis of an input/output map describing the input/output conditions for the individual drive devices and of the operational sequence of said drive devices in the production line.
Claim 12
Dependent Claim
27 words
An apparatus according to claim 5, wherein when said actual operation time is substantially equal to said reference time, it is determined that no failure has occurred.
Claim 13
Dependent Claim
27 words
An apparatus according to claim 5, wherein when said actual operation time is considerably longer than said reference time, it is determined that a failure has occurred.
Claim 14
Dependent Claim
123 words
A diagnostic method for a production line controlled in accordance with a ladder program, including a plurality of program elements, and prepared on the basis of a map describing the operations of equipment comprised of a plurality of drive devices, said method comprising the steps of: a: storing in said map, reference operation times necessary for the execution of the program elements of said ladder program and corresponding respectively to the operations of said drive devices; b: comparing the elapsed time after the execution start of each of said drive devices in said ladder program with the corresponding one of said reference operation times; and c: locating, on the basis of the results of said comparison, any malfunctioning section of said production line.
Claim 15
Dependent Claim
123 words
A diagnostic method for a production line controlled in accordance with a ladder program, including a plurality of program elements, and prepared on the basis of a map describing the operations of equipment comprised of a plurality of drive devices, said method comprising the steps of: a: storing in said map, reference operation times necessary for the execution of the program elements of said ladder program and corresponding respectively to the operations of said drive devices; b: comparing the elapsed time after the execution start of each of said drive devices in said ladder program with the corresponding one of said reference operation times; and c: locating, on the basis of the results of said comparison, any malfunctioning section of said production line.
Claim 16
Dependent Claim
39 words
An apparatus according to claim 12, wherein said elapsed time and said reference operation time are stored in a single memory, and wherein, in said step b, said elapsed time is updated and compared with said reference operation time.
Claim 17
Dependent Claim
78 words
An apparatus according to claim 12, wherein said map is an operation step map including the drive condition for one of said drive devices, the condition for confirming the operation of said one drive device, said reference time, and said elapsed time, and said operation step map is prepared on the basis of an input/output map describing the input/output conditions for the individual drive devices and of the operational sequence of said drive devices in the production line.
Claim 18
Dependent Claim
27 words
An apparatus according to claim 12, wherein when, in step b, said elapsed time has exceeded said reference time, it is determined that a failure has occurred.
Claim 19
Dependent Claim
168 words
A diagnostic method for a production line comprising a plurality of drive devices in which the operation of one drive device is represented by at least one operation step, the operation of the entire production line is represented by a plurality of operation blocks, each operation block includes at least one of said operation steps, each operation step includes a confirming operation by a confirmation device for confirming the operation of the corresponding drive device, and each one of said operation blocks operates independently of the other operation blocks from the start to end thereof; said method comprising the steps of: a: checking, when activating a ladder program of one operation block, the conditions of all the output confirmation devices of the operation steps of those operation blocks which are on the upstream side of and connected with said one operation block; and b: determining that a failure has occurred when the condition of any one of said output confirmation devices is different from a predetermined corresponding condition.
Claim 20
Dependent Claim
168 words
A diagnostic method for a production line comprising a plurality of drive devices in which the operation of one drive device is represented by at least one operation step, the operation of the entire production line is represented by a plurality of operation blocks, each operation block includes at least one of said operation steps, each operation step includes a confirming operation by a confirmation device for confirming the operation of the corresponding drive device, and each one of said operation blocks operates independently of the other operation blocks from the start to end thereof; said method comprising the steps of: a: checking, when activating a ladder program of one operation block, the conditions of all the output confirmation devices of the operation steps of those operation blocks which are on the upstream side of and connected with said one operation block; and b: determining that a failure has occurred when the condition of any one of said output confirmation devices is different from a predetermined corresponding condition.
Claim 21
Dependent Claim
62 words
A method according to claim 16, wherein when said production line is at a stop, checking is performed on the condition of the output confirmation device in each of the operation steps of those operation blocks which are on the upstream side of and connected with any of said operation blocks which has not been activated, whereby any malfunctioning section is located.
Claim 22
Dependent Claim
50 words
A method according to claim 16, wherein the period between the termination of the operations of one block and the activation of the operation block which is on the downstream side of said one operation block, is monitored, thereby locating any of said operation blocks which has not been activated.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-04-24 | 1998-10-24 | 1999-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-04-24 | 2002-10-24 | 2003-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-04-24 | 2006-10-24 | 2007-04-25 | $7700.00 | Window Closed / Lapsed |