Method and apparatus for analyzing and recording downtime of a manufacturing process

• US 5,327,349 A
• Filed: 04/15/1993
• Issued: 07/05/1994
• Est. Priority Date: 04/15/1993
• Status: Expired due to Term

• Current Assignee: Square D Company (Schneider Electric SE)
• Original Assignee: Square D Company (Schneider Electric SE)
• Inventors: Hoste, Stephen A.
• Primary Examiner(s): Smith, Jerry
• Assistant Examiner(s): TOUSI, CAMERON
• Application Number:
  US08/048,155
• Time in Patent Office: 446 Days
• Field of Search: 364/468, 364/474.11, 364/184-187, 364/478, 364/401-403, 364/153, 364/156, 377/16, 324/537
• US Class Current: 700/110
• CPC Class Codes: G05B 19/41875 characterised by quality surveillance of production
• CPC Class Codes: G07C 3/04 using counting means or digital clocks
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A method and apparatus records downtime and the probable cause of the downtime of a network of programmable logic controllers and other microprocessor based devices for controlling of a manufacturing process. The method and apparatus also records the total downtime by separate causes and a total downtime of all causes encountered. The apparatus further records the number of times each cause occurred and a total number of all causes encountered. A graphical display provides a visual presentation of the number of times each cause occurred and the total downtime for each cause that occurred in Pareto chart form. The method provides for prioritizing alarms associated with the cause of a downtime and the apparatus has means for deciding which alarm notification, based on the alarm priority and therefore, its corresponding cause, recorded the most number of times it caused a downtime.

Claims

1. An operator interface module connected to a network of programmable logic controllers and other microprocessor based devices controlling a manufacturing process, said operator interface module for analyzing and recording downtime of said manufacturing process, and said operator interface module comprising:

a. a network interface module for connecting to said network;

b. a control processor;

c. a communications processor connected between said network interface module and said control processor, said communications processor for controlling communications between said operator interface module and said network of programmable logic controllers and other microprocessor based devices;

d. memory means accessible by said communications processor and said control processor;

e. an alarm handler connected to said control processor, said alarm handler for receiving a plurality of alarms from said network indicative of a downtime event of said manufacturing process, for determining which of said plurality of alarms caused said downtime event, and for determining an elapsed time of said downtime event;

f. alarm data registers accessible by said alarm handler and said control processor, said alarm data registers for storing data by said alarm handler related to said downtime event for each of said plurality of received alarms;

g. display means connected to said control processor;

h. keyboard entry means connected to said control processor;

i. wherein said control processor accesses said data stored in said alarm data registers and provides first and second data summary tables in said memory means, said first summary table for storing data based on total number of downtime incidents for each of said plurality of alarms and said second summary table for storing data based on total elapsed time of downtime incidents for each of said plurality of alarms; and

j. wherein said first and second summary tables are directly accessible by said network of programmable logic controllers and other microprocessor based devices.

2. The operator interface module of claim 1 wherein said memory means further includes a register for storing the total number of all downtime incidents from all alarms.

3. The operator interface module of claim 1 wherein said memory means further includes a register for storing the total elapsed time of all downtime incidents from all alarms.

4. The operator interface module of claim 1 wherein said data stored in said alarm data registers consists of an alarm number, an alarm priority level, a trade classification, a total accumulated downtime, and a total number of downtime incidents for each of said plurality of received alarms.

5. The operator interface module of claim 4 wherein said alarm priority level is for determining by said alarm handler which of said plurality of alarms caused said downtime event.

6. The operator interface module of claim 4 wherein said alarm priority level is determined by an operator of said manufacturing process and manually entered by said keyboard entry means.

7. The operator interface module of claim 4 wherein data in said first summary table includes an alarm number and the total accumulated downtime and trade classification associated with said alarm number, and wherein said control processor collects said data from said alarm data registers and sorts said data for a predetermined number of alarms in descending order, based on said total accumulated downtime.

8. The operator interface module of claim 7 wherein said display means connected to said control processor provides a visual presentation of said first summary table based on said alarm number and said total accumulated downtime.

9. The operator interface module of claim 4 wherein data in said second summary table includes an alarm number and the total number of downtime incidents and trade classification associated with said alarm number, and wherein said control processor collects said data from said alarm data registers and sorts said data for a predetermined number of alarms in descending order, based on said total number of downtime incidents.

10. The operator interface module of claim 9 wherein said display means connected to said control processor provides a visual presentation of said second summary table based on said alarm number and said total number of downtime incidents.

11. A method for analyzing downtime of a network of programmable logic controllers and other microprocessor based devices controlling a manufacturing process, said method operating in an operator interface module and comprising:

a. setting an alarm priority level for each of a plurality of alarms signals;

b. receiving a plurality of alarms from said network of programmable logic controllers and other microprocessor based devices indicating a start of a downtime event;

c. starting an elapsed timer for recording total length of time of said downtime event;

d. selecting one of said plurality of received alarms as a cause of said downtime event based on said alarm priority level of each of said received alarms;

e. incrementing by one, one of a plurality of incident counters, said one incident counter assigned to said selected alarm, and said increment counter for recording total number of times said alarm caused said downtime incident;

f. adding total length of time of said downtime event to one of a plurality of elapsed downtime registers, said one elapsed downtime register assigned to said selected alarm, and said elapsed downtime register for recording total elapsed downtime said alarm caused said downtime incident;

g. generating a downtime incident summary table from said plurality of incident counters, said summary table listing a predetermined number of said alarms and identifying said alarm by an alarm number, said generation of said downtime summary table further including sorting said alarms in descending order based on said total number of times said alarm caused downtime incidents;

h. generating a downtime summary table from said plurality of elapsed downtime registers, said summary table listing a predetermined number of said alarms and identifying said alarm by an alarm number, said generation of said downtime summary table further including sorting said alarms in descending order based on said total elapsed downtime when said alarm caused downtime incidents;

i. displaying a portion of said downtime incident summary table in bar chart form, said display indicating said alarm number and its respective total number of downtime incidents, said display in descending order based on said downtime incidents; and

j. displaying a portion of said downtime summary table in bar chart form, said display indicating said alarm number and its respective total elapsed downtime, said display in descending order based on said total elapsed downtime.