Patent Description:
To operate certain electrical components (e.g., modems, communication devices) that may be used to control and monitor industrial automation equipment, these electrical components may be designed to operation under certain electrical conditions. For example, communication systems may expect to receive a certain voltage level as an input voltage, be coupled to a conductor having a certain line impedance, or the like. Industrial automation equipment often use redundant electrical components and devices to ensure that the respective equipment continues to operate in case that one of the electrical components or devices coupled to the equipment malfunctions or becomes unavailable. It is now recognized that providing improved systems and methods for ensuring that the redundant electrical components and devices maintain the expected electrical conditions for the communication systems when one of the redundant electrical components or devices becomes unavailable are desirable.

<CIT> relates to an arrangement with a plurality of peripheral units and a sensor, where each of the peripheral units includes a connection for connecting the sensor to a supply voltage, includes a sensor input for connecting the sensor and also includes a measuring resistor for acquiring a sensor current that represents a signal state, where a redundant acquisition and evaluation of the sensor current or a redundant operation of the sensor is permitted on the plurality of peripheral units via suitable measures.

<CIT> relates to a bus system that requires a termination resistor and an information processing apparatus having the bus system.

<CIT> relates to an assembly with at least two redundant analog input units for a measurement current. At least two redundant analog input units for a measurement current have analog inputs which are connected in parallel and upon which voltage measuring devices directly lie to convert respectively applied voltages into a digital measurement value, where in order to detect errors, in particular in order to detect wire breakage, each analog input unit compares its generated measurement value with a threshold and outputs an error message. If a measurement value is detected that falls below the threshold, where if the analog input of the analog input unit is in the low resistance state, then the at least one other analog input unit is additionally caused to assume a current measuring function and switch the analog input of the analog input unit to a low resistance state.

It is the object of the present invention to improve the reliability of prior art systems.

Within the scope of the invention, one or more specific embodiments will be described below.

Embodiments of the present disclosure are generally directed towards improving high availability systems. High availability systems generally refer to redundant monitoring and/or controlling of a sensor, a device, or the like. In certain embodiments, high availability systems may be available for use with industrial automation equipment to ensure that the equipment is operating continuously. High availability systems may include redundant monitoring of a sensor output received from one of a number of parallel-connected input modules. Each input module may measure an electrical property (e.g., a current, voltage, etc.) associated with a sensor (e.g., a current sensor, a temperature sensor, etc.), perform a control operation with respect to the connected industrial automation equipment, or the like.

In some embodiments, each input module may be communicatively coupled to communication circuit, which may transmit and receive data between the input module and other electronic devices (e.g., gateway, control system). To maintain operations of the communication circuit, the communication circuit may operate based on certain input electrical properties. For example, the communication circuit may use an input voltage within a certain range of voltages to power on and perform its respective operations. In addition, some communication circuits may expect a certain line impedance to be present on a connected input module to perform its respective operations. As such, each input module or a connected terminal base may include a resistor that corresponds to the expected line impedance for the communication circuit. In certain embodiments, the terminal base may include circuitry to receive a number of input modules to provide redundancy among the input modules. To ensure that the desired line impedance remains for the communication circuit, the terminal base circuitry and the input module circuitry may be designed in a certain manner to ensure that the expected line impedance is connected to the communication circuitry when both of the redundant input modules are connected and when one of the redundant input modules is removed or becomes unavailable. Additional details regarding various schemes for maintaining the line impedance when one of the input modules is removed are described below with reference to <FIG>.

By way of introduction, <FIG> is a block diagram of an example control and monitoring system <NUM> that may be used in accordance with an embodiment of the present disclosure. The control and monitoring system <NUM> may include a human machine interface (HMI) <NUM> and a control/monitoring device or automation controller <NUM> adapted to interface with devices (e.g., sensor <NUM>) that may monitor various types of industrial automation equipment <NUM>. It should be noted that the control and monitoring system <NUM> may be implemented by certain network strategies. For example, an industry standard network may be employed, such as Highway Addressable Remote Transducer (HART) protocol or DeviceNet, to enable data transfer. Such networks permit the exchange of data in accordance with a predefined protocol, and may provide power for operation of networked elements.

The industrial automation equipment <NUM> may take many forms and include devices for accomplishing many different and varied purposes. For example, the industrial automation equipment <NUM> may include machinery used to perform various operations in a compressor station, an oil refinery, a batch operation for making food items, a mechanized assembly line, and so forth. Accordingly, the industrial automation equipment <NUM> may comprise a variety of operational components, such as electric motors, valves, actuators, temperature elements, pressure sensors, or a myriad of machinery or devices used for manufacturing, processing, material handling, and other applications.

Additionally, the industrial automation equipment <NUM> may include various types of equipment that may be used to perform the various operations that may be part of an industrial application. For instance, the industrial automation equipment <NUM> may include electrical equipment, hydraulic equipment, compressed air equipment, steam equipment, mechanical tools, protective equipment, refrigeration equipment, power lines, hydraulic lines, steam lines, and the like. Some example types of equipment may include mixers, machine conveyors, tanks, skids, specialized original equipment manufacturer machines, and the like. In addition to the equipment described above, the industrial automation equipment <NUM> may also include controllers, input/output modules, motor control centers, motors, HMIs, operator interfaces, contactors, starters, additional sensors, actuators, drives, relays, protection devices, switchgear, compressors, sensor, actuator, firewall, network switches (e.g., Ethernet switches, modular-managed, fixed-managed, service-router, industrial, unmanaged, etc.) and the like.

In certain embodiments, one or more properties of the industrial automation equipment <NUM> may be monitored by certain equipment for regulating control variables used to operate the industrial automation equipment <NUM>. For example, a sensor <NUM> may monitor various properties of the industrial automation equipment <NUM>.

In some cases, the industrial automation equipment <NUM> may be associated with devices used by other equipment. For instance, scanners, gauges, valves, flow meters, and the like may be disposed on industrial automation equipment <NUM>. Here, the industrial automation equipment <NUM> may receive data from the associated devices and use the data to perform their respective operations more efficiently. For example, a controller (e.g., the control/monitoring device <NUM>) of a motor drive may receive data regarding a temperature of a connected motor and may adjust operations of the motor drive based on the data.

The sensor <NUM> may be a device adapted to provide information regarding process conditions. The sensor <NUM> may be utilized to monitor the industrial automation equipment <NUM>. In particular, the sensor <NUM> may be utilized within process loops that are monitored by the control/monitoring device <NUM> and/or the HMI <NUM>. Such a process loop may be activated based on process inputs (e.g., input from the sensor <NUM>) or direct operator input received through the HMI <NUM>. As illustrated, the sensor <NUM> is in communication with the control/monitoring device <NUM>. Further, the sensor <NUM> may be assigned a particular address in the control/monitoring device <NUM> and receive power from the control/monitoring device <NUM> or attached modules. There may be any number of the sensors <NUM> electrically coupled to the control/monitoring device <NUM> monitoring the industrial automation equipment <NUM>.

The input modules <NUM> may be installed or removed from the control and monitoring system <NUM> via expansion slots, bays, a terminal base <NUM>, or other suitable mechanisms. The terminal base <NUM> may electrically couple to any number of various components, such as the input modules <NUM>, and route signals between the various components and the control/monitoring device <NUM>. In certain embodiments, the input modules <NUM> may be included to add functionality to the control/monitoring device <NUM>, or to accommodate additional process features. For instance, the input modules <NUM> may communicate with the sensors <NUM> added to monitor the industrial automation equipment <NUM>. It should be noted that the input modules <NUM> may communicate directly to sensors <NUM> through hardwired connections or may communicate through wired or wireless sensor networks, such as HART or IOLink. In some embodiments, the input modules <NUM> may be in the form of input/output modules.

Generally, the input modules <NUM> may serve as an electrical interface to the control/monitoring device <NUM> and may be located proximate or remote from the control/monitoring device <NUM>, including remote network interfaces to associated systems. In such embodiments, data may be communicated with the remote input modules <NUM> over a common communication link, or network, wherein modules on the network communicate via a standard communications protocol. Many industrial controllers can communicate via network technologies such as Ethernet (e.g., IEEE802. <NUM>, TCP/IP, UDP, EtherNet/IP, and so forth), ControlNet, DeviceNet or other network protocols (Foundation Fieldbus (H1 and Fast Ethernet) Modbus TCP, Profibus) and also communicate to higher level computing systems.

In the illustrated embodiment, several of the input modules <NUM> may transfer signals between the control/monitoring device <NUM> and the industrial automation equipment <NUM>. As illustrated, the sensor <NUM> may communicate with the control/monitoring device <NUM> via the several input modules <NUM> electrically coupled to the control/monitoring device <NUM>. The several input modules <NUM> may be utilized redundantly, such that if one of the several input modules <NUM> becomes unavailable, one of the remaining input modules <NUM> may operate in its place. In this manner, the control and monitoring system <NUM> may continue operating without interruption despite an input module <NUM> becoming unavailable.

In certain embodiments, the control and monitoring system <NUM> (e.g., the HMI <NUM>, the control/monitoring device <NUM>, the sensors <NUM>, the input modules <NUM>) and the industrial automation equipment <NUM> may make up an industrial application <NUM>. The industrial application <NUM> may involve any type of industrial process or system used to manufacture, produce, process, or package various types of items. For example, the industrial applications <NUM> may include industries such as material handling, packaging industries, manufacturing, processing, batch processing, and the like. In certain embodiments, the control/monitoring device <NUM> may be communicatively coupled to a computing device <NUM> and a cloud-based computing system <NUM>. In this network, input and output signals generated from the control/monitoring device <NUM> may be communicated between the computing device <NUM> and the cloud-based computing system <NUM>.

With the foregoing in mind, <FIG> is an example schematic diagram that allows redundant input modules <NUM> coupled to the terminal base <NUM> (e.g., that may be part of the control and monitoring system <NUM>) to maintain a certain amount of line impedance for communication circuitry connected to each input module <NUM>. For instance, a redundant input module system <NUM> depicted in <FIG> provides an example manner in which a certain amount of line impedance may be maintained for communication circuitry coupled to each input module when one of the input modules is removed.

Referring to <FIG>, the redundant input module system <NUM> may include the terminal base <NUM> connected to input module <NUM> and input module <NUM>. The operations and properties of the input module <NUM> and <NUM> may correspond to the input module <NUM> described above. Each respective input module <NUM> and <NUM> may be able to communicatively couple to communication circuit <NUM> and <NUM>, respectively. Although the redundant input module system <NUM> illustrates the input modules <NUM> and <NUM> being communicatively coupled to two different communication circuits <NUM> and <NUM>, it should be noted that, in some embodiments, the input modules <NUM> and <NUM> may be coupled to any suitable number of communication circuits, including one.

In some embodiments, each input module <NUM> and <NUM> may include additional circuit components that enable the respective module to perform its respective operations. By way of example, the input modules <NUM> and <NUM> may include analog-to-digital converter (ADC) circuits <NUM> and <NUM> that may convert analog voltages received by the input modules <NUM> and <NUM> into digital voltage interpretable by internal circuitry within the input modules <NUM> and <NUM>. In some embodiments, these additional circuit components may expect certain electrical properties (e.g., impedance) to be present to perform their respective operations.

As mentioned above, the communication circuit <NUM> and <NUM> may expect a certain amount of line impedance to be present on the conductor or terminal connecting the communication circuit <NUM> and <NUM> to the input modules <NUM> and <NUM>, respectively. For example, communication circuits <NUM> and <NUM> implementing HART functionality may expect a certain amount of resistance (e.g., <NUM> ohms) to be coupled thereto. To ensure that the same amount of line impedance is available for each communication circuit <NUM> and <NUM> when one of the input modules <NUM> or <NUM> is removed or becomes unavailable, a resistor <NUM> is coupled across two terminals or nodes of the terminal base <NUM>. The resistance of the resistor <NUM> may correspond to the expected resistance or line impedance associated with the communication circuits <NUM> and <NUM>. In this way, when either input module <NUM> or <NUM> become unavailable, the same line impedance remains connected to the communication circuits <NUM> or <NUM> due to the resistor <NUM>.

Although the redundant input module system <NUM> of <FIG> may maintain a certain amount of line impedance when either input module <NUM> of <NUM> becomes unavailable, the design of the redundant input module system <NUM> has some shortcomings. For example, terminal bases <NUM> are not easily repairable after they are placed in service. As such, if the resistor <NUM> short circuits or becomes unavailable or loses its resistance properties (e.g., degrades), the field wiring to each input module <NUM> and <NUM> would have to be disconnected to replace the terminal base <NUM>, thereby causing the connected industrial automation equipment <NUM> to be powered down or be left unmonitored. In addition, by relying on the resistor <NUM> to provide the line impedance for both communication circuits <NUM> and <NUM>, the resistor <NUM> becomes a single component that potentially disables the operations of the communication circuits <NUM> and <NUM>. That is, the resistor <NUM> does not include any redundancy to ensure that the operations of the redundant input module system <NUM> continue in case the resistor <NUM> becomes unavailable.

Keeping this in mind, <FIG> includes a redundant input module system <NUM> that enables the communication circuits <NUM> and <NUM> to continue to operate with the expected line impedance when either input module <NUM> or <NUM> becomes unavailable, while providing a redundancy for the line impedance in each input module <NUM> and <NUM>. As such, the terminal base <NUM> may avoid including components (e.g., resistors) that may degrade or need replacement.

Referring now to <FIG>, the redundant input module system <NUM> includes the input modules <NUM> and <NUM>, the communication circuits <NUM> and <NUM>, and the ADC circuits <NUM> and <NUM> described above. As shown in <FIG>, the redundant input module system <NUM> includes the terminal base <NUM> without a resistor contained therein. Instead, each of the input modules <NUM> and <NUM> include resistors <NUM>, <NUM>, <NUM>, and <NUM> that are used to provide the expected line impedance for the communication circuits <NUM> and <NUM>.

By way of operation, the input module <NUM> employs a switch <NUM> to control the line impedance provided to the communication circuit <NUM> based on the connection arrangement of the resistors <NUM> and <NUM>. The switch <NUM> may be any suitable type of field-effect transistor (FET) device that may operate (e.g., open/close) based on a gate signal provided to the switch <NUM>. For example, the switch <NUM> may be a metal-oxide-semiconductor field-effect transistor (MOSFET) or other suitable type of switch. It should be noted that although N-type switches are provided in the figures, in some embodiments, P-type switches may be used instead of the N-type switches.

As shown in <FIG>, the resistor <NUM> and the resistor <NUM> are electrically coupled together in series. By way of example, if each resistor <NUM> and <NUM> is <NUM> ohms, the line impedance provided to the communication circuit <NUM> is <NUM> ohms when the switch <NUM> is off (e.g., open). The switch <NUM> is open when the input module <NUM> is coupled to the terminal base <NUM>. That is, a gate <NUM> of the switch <NUM> may be coupled to a node <NUM>, which may be coupled to a pull up resistor <NUM> and a grounding node <NUM> of the input module <NUM>. Since the node <NUM> is coupled to ground via the grounding node <NUM> of the input module <NUM>, the node <NUM> may have <NUM> volts present on it. As such, the voltage provided to the gate <NUM> of the switch <NUM> does not exceed a threshold voltage to turn the switch on (e.g., close).

With this in mind, the input module <NUM> includes a switch <NUM>, a gate <NUM> of the switch <NUM>, a node <NUM>, and a pull up resistor <NUM> that corresponds to the switch <NUM>, the gate <NUM> of the switch <NUM>, the node <NUM>, and the pull up resistor <NUM> described above with respect to the input module <NUM>. As such, when the input modules <NUM> and <NUM> are connected to the terminal base <NUM>, the switch <NUM> may be open because the gate <NUM> of the switch <NUM> may be coupled to the node <NUM>, which may be coupled to a grounding node <NUM> of the input module <NUM>. In addition, to the node <NUM> being coupled to the grounding node <NUM> via the terminal base <NUM>, the node <NUM> may also be coupled to the pull up resistor <NUM>, which may correspond to the pull up resistor <NUM> of the input module <NUM>. However, since the nodes <NUM> and <NUM> are effectively coupled to ground via the terminal base <NUM>, the switches <NUM> and <NUM> remain off (e.g., open). As a result, the resistors <NUM> and <NUM> create a <NUM> ohm resistance on the conductor coupled to the communication circuit <NUM>, while the resistors <NUM> and <NUM> create a <NUM> ohm resistance on the conductor coupled to the communication circuit <NUM>. These two <NUM> ohm resistances are coupled to each other in parallel via the terminal base <NUM>, thereby effectively providing a <NUM> ohm resistance (e.g., expected line impedance) on the conductors coupled both communication circuits <NUM> and <NUM>.

To ensure that the expected line impedance is provided to the communication circuit <NUM> or <NUM> when one of the input modules <NUM> or <NUM> is removed or becomes unavailable, one of the switches <NUM> or <NUM> activates (e.g., turn on, close) to change the effective line impedance provided to the respective communication circuit <NUM> or <NUM>. For instance, if the input module <NUM> is no longer connected to the terminal base <NUM>, the node <NUM> of the input module <NUM> may no longer be coupled to the grounding node <NUM> of the input module <NUM>. Instead, the gate <NUM> of the switch <NUM> may receive a positive voltage that exceeds the threshold voltage of the switch <NUM> via the pull up resistor <NUM>. It should be noted that each of the pull up resistors <NUM> and <NUM> may be coupled to voltage sources V1 and V2, respectively. The voltage sources V1 and V2 may output a voltage that may be available to the respective input modules <NUM> and <NUM>.

With this in mind, the voltage provided to the gate <NUM> of the switch <NUM> via the pull up resistor <NUM> and the voltage source V1 may cause the switch <NUM> to close. The resistor <NUM> may then be shorted out of the circuit for the input module <NUM>. In this way, the effective resistance on the conductor coupled to the communication circuit <NUM> is <NUM> ohms.

It should be understood that although the foregoing discussion of the input modules <NUM> and <NUM> are described using particular resistance values, the recited resistance values are provided as examples to help illustrate the functionality of the embodiments presented herein. Indeed, any suitable resistor having a variety of resistance values may be used in accordance with the embodiments herein based on the expected line impedance that corresponds to the communication circuits <NUM> and <NUM>.

Based on the operation of the redundant input module system <NUM> described above, the input modules <NUM> and <NUM> automatically adjust their field side impedance as either input module <NUM> or <NUM> is removed or inserted. Advantageously, the redundant input module system <NUM> may not involve additional field wiring of the terminal base <NUM> upon insertion or removal of the respective input module <NUM> or <NUM>. In some embodiments, parallel switches <NUM> or <NUM> may be added to the input modules <NUM> or <NUM> to provide redundant switches that control the effective line impedance of the input modules <NUM> or <NUM>.

Keeping the foregoing in mind, <FIG> illustrates another embodiment of a redundant input module system <NUM> that enables the communication circuits <NUM> and <NUM> to continue to operate with the expected line impedance when either input module <NUM> or <NUM> becomes unavailable, while providing a redundancy for the line impedance in each input module <NUM> and <NUM>.

As shown in <FIG>, the redundant input module system <NUM> may include similar components as described above with respect to the redundant input module system <NUM> of <FIG>. However, instead of the switches <NUM> and <NUM> being controlled based on the connection to ground via the terminal base <NUM>, the redundant input module system <NUM> may include control systems <NUM> and <NUM> for the input modules <NUM> and <NUM>, respectively, to facilitate the operations of the switches <NUM> and <NUM>, respectively.

Before proceeding, it should be mentioned that the control systems <NUM> and <NUM> may include any suitable control system implemented via any suitable computing device. As such, the control system <NUM> and <NUM> may include a communication component, a processor, a memory, a storage, input/output (I/O) ports, and the like. The communication component may be a wireless or wired communication component that may facilitate communication between other communication capable devices. The processor may be any type of computer processor or microprocessor capable of executing computer-executable code. The memory and the storage may be any suitable articles of manufacture that can serve as media to store processor-executable code, data, or the like. These articles of manufacture may represent computer-readable media (e.g., any suitable form of memory or storage) that may store the processor-executable code used by the processor to perform the presently disclosed techniques. The memory and the storage may also be used to store the data, analysis of the data, the software applications, and the like. The memory and the storage may represent non-transitory computer-readable media (e.g., any suitable form of memory or storage) that may store the processor-executable code used by the processor to perform various techniques described herein. It should be noted that non-transitory merely indicates that the media is tangible and not a signal.

In some embodiments, the control systems <NUM> and <NUM> may include general purpose input/output (I/O) ports that may transmit data, receive data, output voltages, receive voltages, and the like. For example, the control systems <NUM> and <NUM> may output voltages via I/O ports <NUM> and <NUM>, respectively. In the same manner, the control systems <NUM> and <NUM> may receive sensed voltages via ports <NUM> and <NUM>, respectively.

In addition to outputting and receiving voltages, the control systems <NUM> and <NUM> may output a gate signal to the switches <NUM> and <NUM> to control their respective operations. For example, the control system <NUM> may control the operation of the switch <NUM> based on whether it detects the presence of the input module <NUM> being connected to the terminal base <NUM>. It should be noted that, in some embodiments, the pull up resistors <NUM> and <NUM> and the voltages sources V1 and V2 may not be included in the redundant input module system <NUM>. Instead, the control systems <NUM> and <NUM> may output gate signals to control the state of the switches <NUM> and <NUM> without the pull up resistors <NUM> and <NUM>.

To detect the presence of the input module <NUM> being connected to the terminal base <NUM>, the control systems <NUM> and <NUM> may coordinate their operations in a particular manner. By way of example, the control system <NUM> may output a logic high voltage via the I/O port <NUM>, which may be coupled to a sense resistor <NUM> within the input module <NUM>. At the same time, the control system <NUM> may output a logic low voltage via the I/O port <NUM>, which may be coupled to a sense resistor <NUM> of the input module <NUM>. The sense resistors <NUM> and <NUM> may provide some resistance across a checkpoint conductor <NUM> that couples the input modules <NUM> and <NUM> to each other via the terminal base <NUM>.

When the input modules <NUM> and <NUM> and coupled to each other via the terminal base <NUM> and the checkpoint conductor <NUM>, the control system <NUM> may output the logic high voltage to the sense resistor <NUM> and the control system <NUM> may output a logic low voltage to the sense resistor <NUM>. As a result, the voltage present on the checkpoint conductor <NUM> may be some value between the logic high voltage and the logic low voltage. The control systems <NUM> and <NUM> may monitor the voltage of the checkpoint conductor <NUM> via the ports <NUM> and <NUM>, respectively.

In response to the input module <NUM> being removed from the terminal base <NUM>, the voltage detected by the control system <NUM> may swing towards the logic high voltage due to the loss of the logic low voltage on the checkpoint conductor <NUM>. Upon detecting this voltage swing, the control system <NUM> may determine that the input module <NUM> has been removed and may output a gate signal to the gate <NUM> of the switch <NUM>. The gate signal may cause the switch <NUM> to close, thereby shorting out the resistor <NUM> and providing a line impedance to the communication circuit <NUM> that corresponds to the resistance of the resistor <NUM>. Like the redundant input module system <NUM> of <FIG>, when both input modules <NUM> and <NUM> of the redundant input module system <NUM> are coupled to the terminal base <NUM>, the effective line impedance available for each communication circuit <NUM> and <NUM> corresponds to the series resistance of resistors <NUM> and <NUM> in parallel connection with the series resistance of resistors <NUM> and <NUM>, as described above with respect to <FIG>.

Claim 1:
A redundant input module system (<NUM>), comprising:
a control device configured to control one or more operations of industrial automation equipment;
a terminal base (<NUM>) configured to couple to the control device;
a first input module (<NUM>) configured to couple to the terminal base, wherein the first input module comprises a first resistor (<NUM>) coupled in series with a second resistor (<NUM>);
a second input module (<NUM>) configured to couple to the terminal base, wherein the second input module comprises a third resistor (<NUM>) coupled in series with a fourth resistor (<NUM>);
wherein the terminal base is configured to electrically couple the first resistor and the second resistor in parallel with the third resistor and the fourth resistor when the first input module and the second input module are coupled to the terminal base,
wherein the first resistor, the second resistor, the third resistor and the fourth resistor contribute to a line impedance when the first input module and the second input module are coupled to the terminal base,
wherein the first input module is configured to electrically remove the second resistor from circuitry of the first input module in response to the second input module being disconnected from the terminal base,
wherein the first input module comprises a switch (<NUM>) configured to electrically remove the second resistor from the circuitry of the first input module,
wherein the first resistor provides a first resistance, and
wherein the first resistor coupled in series with the second resistor forms a first electrical component, wherein the third resistor coupled in series with the fourth resistor forms a second electrical component, and wherein the first electrical component coupled in parallel with the second electrical component provides the first resistance.