Industrial Control Module Providing Universal I/O

• US 20190324429A1
• Filed: 04/23/2018
• Published: 10/24/2019
• Est. Priority Date: 04/23/2018
• Status: Active Grant

• Current Assignee: Rockwell Automation Technologies Incorporated (Rockwell Automation, Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Rockwell Automation, Inc.)
• Inventors: O'Connell, John R., Shah, Rajesh R.
• Granted Patent: US 10,684,611 B2
• Time in Patent Office: Days
• CPC Class Codes: G05B 19/0423 Input/output
• CPC Class Codes: G05B 19/054 Input/output
• CPC Class Codes: G05B 19/41845 characterised by system universality, reconfigurability, modularity
• CPC Class Codes: G05B 2219/21012 Configurable I-O
• CPC Class Codes: G05B 2219/21123 Impedance matching
• CPC Class Codes: G05B 2219/33106 Configure I-O by using logical and physical address
• CPC Class Codes: G06F 13/102 where the programme performs an interfacing function, e.g. device driver G06F13/105 takes precedence; scheduling within device drivers G06F9/52; contention policies within device drivers G06F9/4881
• CPC Class Codes: H03F 2200/321 Use of a microprocessor in an amplifier circuit or its control circuit
• CPC Class Codes: H03F 2203/45151 At least one resistor being added at the input of a dif amp
• CPC Class Codes: H03F 3/45071 with semiconductor devices only
• CPC Class Codes: H03K 17/6877 the control circuit comprising active elements different from those used in the output circuit

Abstract

An industrial control I/O module for interfacing with industrial control equipment, such as sensors and actuators, can be configured to dynamically provide differing resistances in each channel as may be required for reliably achieving particular modes of operation in the channel. Providing differing resistances in such channels flexibly allows different modes in the channel to provide universal I/O capability. Modes of operation could include, for example, digital output, digital input, analog output, analog input and the like, in the same channel, but at different times. In one aspect, a processor or voltage divider can be used to control an amplifier, with feedback, driving a transistor in a channel to dynamically adjust resistance in the channel by selectively biasing the transistor to achieve a resistance in the channel suitable for the selected mode.

Claims

1. A module for interfacing with industrial control equipment, comprising:

a terminal configured to receive an electrical conductor in a channel interfacing with industrial control equipment;

a variable resistance device connected to the terminal providing a resistance in the channel; and

a control circuit connected to the variable resistance device,

wherein the control circuit is configured to control the variable resistance device to adjust the resistance in the channel for a given mode selected from a plurality of modes, wherein each mode of the plurality of modes configures a different resistance in the channel.

2. The module of claim 1, wherein the terminal is a screw terminal, and wherein the variable resistance device is a transistor.

3. The module of claim 2, wherein the control circuit comprises a processor connected to an amplifier, wherein the transistor is a Field Effect Transistor (FET), and wherein the amplifier drives a gate of the FET.

4. The module of claim 3, further comprising a resistor for current sensing connected to the FET, wherein the resistor is further connected to a first input of the amplifier and the processor is connected to a second input of the amplifier.

5. The module of claim 3, wherein the given mode is determined by the processor from user input.

6. The module of claim 2, wherein the control circuit comprises a resistor divider connected to an amplifier, wherein the transistor is a Field Effect Transistor (FET), and wherein the amplifier drives a gate of the FET.

7. The module of claim 6, wherein the resistor divider comprises a resistor in series with a digital potentiometer.

8. The module of claim 7, further comprising a processor for configuring the digital potentiometer, wherein the given mode is determined by the processor from user input, and wherein the processor configures the digital potentiometer according to the given mode.

9. The module of claim 1, wherein the plurality of modes includes modes for digital output, digital input, analog output and analog input.

10. The module of claim 9, wherein the control circuit controls the variable resistance device to provide a higher resistance in the channel when the mode is for digital input and a lower resistance in the channel when the mode is for analog input.

11. The module of claim 9, wherein the plurality of modes further includes a mode for analog input with Highway Addressable Remote Transducer (HART) communications in a 4-20 mA current loop.

12. The module of claim 11, wherein the control circuit controls the variable resistance device to provide a higher resistance in the channel when the mode is for analog input and a lower resistance in the channel when the mode is for analog input with HART communications.

13. The module of claim 9, wherein the control circuit controls the variable resistance device to minimize the resistance in the channel when the mode is for digital output.

14. The module of claim 9, wherein the control circuit controls the variable resistance device to vary the resistance in the channel to maintain a constant current in the channel when the mode is for analog output.

15. The module of claim 9, wherein the terminal is a first terminal in a first channel, and further comprising a second terminal configured to receive an electrical conductor in a second channel interfacing with industrial control equipment comprising an actuator, and wherein the second channel provides an output from a power source to the industrial control equipment in the modes for digital output and analog output while the first channel provides a return path.

16. The module of claim 9, wherein the terminal is a first terminal in a first channel, and further comprising a second terminal configured to receive an electrical conductor in a second channel interfacing with industrial control equipment comprising a sensor, and wherein the first channel provides an input from the industrial control equipment in the modes for digital input and analog input while the second channel provides a return path to ground.

17. An industrial control system comprising:

an industrial controller executing a control program for controlling an industrial process;

an I/O module in communication with the industrial controller, the I/O module providing a direct interface to industrial control equipment of the industrial process, the I/O module comprising;

a terminal configured to receive an electrical conductor in a channel interfacing with the industrial control equipment;

a variable resistance device connected to the terminal providing a resistance in the channel; and

a control circuit connected to the variable resistance device,

wherein the control circuit is configured to control the variable resistance device to adjust the resistance in the channel for a given mode selected from a plurality of modes, wherein each mode of the plurality of modes configures a different resistance in the channel.

18. The industrial control system of claim 17, wherein the terminal is a screw terminal, and wherein the variable resistance device is a FET with the control circuit connected to a gate of the FET.

19. The industrial control system of claim 17, wherein the plurality of modes includes modes for digital output, digital input, analog output, analog input and analog input with HART communications.

20. The industrial control system of claim 19, wherein the control circuit controls the variable resistance device to minimize the resistance in the channel when the given mode is for digital output, and wherein the control circuit controls the variable resistance device to vary the resistance in the channel to maintain a constant current in the channel when the given mode is for analog output.