System and method for device sequencing using discrete PLC control

• US 6,897,675 B2
• Filed: 01/09/2003
• Issued: 05/24/2005
• Est. Priority Date: 01/09/2003
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Electronic Data Systems Corporation (Perspecta, Inc.)
• Inventors: Hamilton, Wesley O., Donley, Kevin A.
• Primary Examiner(s): Tokar, Michael
• Assistant Examiner(s): Nguyen, Linh Van
• Application Number:
  US10/339,635
• Publication Number:
  US 20040138767A1
• Time in Patent Office: 866 Days
• Field of Search: 326/38, 326/39, 326/41, 326/47, 326/49, 326/101, 700/17, 700/159
• US Class Current: 326/38
• CPC Class Codes: G05B 19/056 Programming the PLC
• CPC Class Codes: G05B 2219/13066 Execute next step if state, control zone changes
• CPC Class Codes: G05B 2219/13078 Sequence operation and interlock set programs are separated
• CPC Class Codes: G05B 2219/13085 Plc controls several machines in sequence

Abstract

A system and apparatus for discrete PLC control using word sequences in a data table for controlling a device on an assembly line. The data table contains sequencing information which defines, for each station on the line, a series of operations with corresponding setup and operation parameters. By placing the sequencing information in a data table, programming or changing the series of operations for a PLC is made much more simple and efficient.

Claims

1. A method for operating a programmable-logic-controller controlled device, comprising:

providing a programmable logic controller having at least one input and at least one output;

providing a data table, stored in a computer-readable medium, readable by the programmable logic controller;

reading a first word from the data table;

performing an operation at a first station, controlled by the programmable logic controller, according to the contents of the first word.

2. The method of claim 1, further comprising

evaluating the first word, and

if the first word equals a predetermined value, then reading a second word from the data table.

3. The method of claim 1, further comprising

reading a second word from the data table, and

performing a second operation at the first station, according to the contents of the second word.

4. The method of claim 1, wherein the input is connected to a sensor.

5. The method of claim 1, further comprising comparing at least one bit of the first word to the input.

6. The method of claim 1, wherein the input is connected to determine the configuration of the device.

7. The method of claim 1, further comprising configuring the device so that the at least one bit of the first word equals the input.

8. The method of claim 1, wherein the output is connected to control the device.

9. The method of claim 1, wherein the data table contains multiple words, each word corresponding to a device operation and a device configuration.

10. The method of claim 1, wherein the operations of the programmable logic controller can be changed by changing the contents of the data table.

11. An apparatus, comprising:

a programmable logic controller having at least one input and at least one output;

a data table, stored in a computer-readable medium, readable by the programmable logic controller;

at least one device connected to be controlled by the programmable logic controller; and

at least one word stored in the data table;

wherein the word defines a device operation and corresponding operation parameters.

12. The apparatus of claim 11, further comprising

a plurality of words stored in the data table, wherein each word defines a different device operation and corresponding operation parameters.

13. The apparatus of claim 11, wherein the device is an electric torque gun.

14. The apparatus of claim 11, further comprising at least one sensor connected to be read by the programmable logic controller.

15. The apparatus of claim 14, wherein the sensor indicates the present position of the device.

16. The apparatus of claim 14, wherein the sensor indicates the present configuration of the device.

17. The apparatus of claim 11, wherein if the word is equal to zero, then no operation is performed.

18. The apparatus of claim 11, further comprising configuring the device so that the at least one bit of the first word equals the input.

19. The apparatus of claim 11, wherein the data table contains multiple words, each word corresponding to a device operation and a device configuration.

20. The apparatus of claim 11, wherein the operations of the programmable logic controller can be changed by changing the contents of the data table.

21. The apparatus of claim 11, wherein the programmable logic controller controls multiple devices on multiple stations of an assembly line.

22. The apparatus of claim 11, wherein the contents of the data table can be changed without changing the programming of the programmable logic controller.