Programmable logic controller override output board

• US 6,392,557 B1
• Filed: 09/20/2000
• Issued: 05/21/2002
• Est. Priority Date: 09/20/2000
• Status: Expired due to Term

• Current Assignee: Kreuter Manufacturing Co., Inc.
• Original Assignee: Kreuter Manufacturing Co., Inc.
• Inventors: Kreuter, Paul E.
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US09/665,081
• Time in Patent Office: 608 Days
• Field of Search: 340/999, 340/635, 340/638, 340/639, 340/654, 340/309.15, 340/825.06, 340/825.22, 439/59, 439/157, 439/629
• US Class Current: 307/112
• CPC Class Codes: G05B 19/05 Programmable logic controllers, e.g. simulating logic interconnections of signals according to ladder diagrams or function charts
• CPC Class Codes: G05B 2219/15005 Set switches defining control function

Abstract

The invention is an override board releasably mounted in a programmable logic controller. The override board is used to control an individual output of the programmable logic controller. The override board includes a manual switch mounted to a printed circuit board assembly. The manual switch has an “auto” position, an “on” position and an “off” position. An output device is also mounted to the printed circuit board assembly and is electrically connected to the manual switch. Placing the manual switch in the “auto” position transfers control of the override board to the programmable logic controller. Placing the manual switch in the “on” position energizes the output device. Placing the manual switch in the “off” position de-energizes the output device.

Claims

1. An override board used to control an output of a programmable logic controller, the override board comprising:

a printed circuit board assembly;

a connection means secured to the printed circuit board assembly and configured so as to allow the override board to be releasably secured from a mating connection means disposed on the programmable logic controller;

a manual switch assembly, the manual switch having a first position, a second position and a third position; and

output device mounted to the printed circuit board assembly, wherein the output device is electrically connected to the manual switch and wherein placing the manual switch in the first position transfers control of the override board to the programmable logic controller, placing the manual switch in the second position energizes the output device, and placing the manual switch in the third position de-energizes the output device.

2. The board of claim 1 and further comprising:

a feedback circuit on the printed circuit board assembly which provides a signal to the programmable logic controller indicating the position of the manual switch.

3. The board of claim 1 and further comprising:

a light emitting device which provides a visual indication of whether the output device is energized.

4. The board of claim 3 wherein the light emitting device is a light emitting diode.

5. The board of claim 1 wherein the output device is an electro-mechanical relay having contacts in a normally open position.

6. The board of claim 1 wherein the output device is a normally closed electro-mechanical relay having contacts in a normally closed position.

7. The board of claim 1 wherein the output device is a triac.

8. The board of claim 1 wherein the output device is a manually adjustable potentiometer.

9. The board of claim 8 wherein the manually adjustable potentiometer controls the voltage of the output of the programmable logic controller.

10. The board of claim 8 wherein the manually adjustable potentiometer controls the amperage of the output of the programmable logic controller.

11. A method for controlling the output of a programmable logic controller comprising:

releasably inserting a first override board into a programmable logic controller such that the first override board interfaces with a logic circuit of the programmable logic controller;

providing a load signal from an output device attached on the first override board as the output of the programmable logic controller;

positioning a manual switch attached to the first override board into a first position having an energizing effect on the output device;

positioning the manual switch into a second position having a de-energizing effect on the output device; and

positioning the manual switch into a third position, transferring control of the output of the programmable logic controller to the logic circuit of the programmable controller.

12. The method of claim 11 and further comprising:

providing a feedback signal from the override board to the programmable logic controller indicating the position of the manual switch.

13. The method of claim 11 and further comprising:

visually indicating when the load signal is being provided from the output device.

14. The method of claim 11 wherein the step of providing a load signal further comprises:

switching the load signal through an electromechanical relay having normally open contacts.

15. The method of claim 11 wherein the step of providing a load signal further comprises:

switching the load signal through an electro-mechanical relay having normally closed contacts.

16. The method of claim 11 wherein the step of providing a load signal further comprises:

switching the load signal through a triac.

17. The method of claim 11 wherein the step of providing a load signal further comprises:

manually adjusting the voltage of the load signal using a potentiometer.

18. The method of claim 11 wherein the step of providing a load signal further comprises:

manually adjusting the amperage of the load signal using a potentiometer.

19. The method of claim 11, further comprising:

removing the first override board from the programmable logic controller;

releasably inserting a second override board into the programmable logic controller such that the second override board interfaces with the logic circuit of the programmable logic controller.

20. An apparatus comprising:

a programmable logic controller including a plurality of controller connectors, and

a plurality of override boards each override board including;

a printed circuit board;

a connector secured to the print circuit board and releasably coupled to one of the controller connectors;

a manual switch assembly having a first position, a second position and a third position;

an output device mounted to the printed circuit board, wherein the output device is electrically connected to the manual switch and wherein placing the manual switch in the first position transfers control of the override board to the programmable logic controller, placing the manual switch in the second position energizes the output device, and placing the manual switch in the third position de-energizes the output device; and

a feedback circuit connecting the programmable logic controller and each override board.