Patent Description:
Process control networks transmit I/O signals to and from field devices under the control of a control system that regulates and controls industrial processes. Field devices include sensors and actuators. Sensors transmit input signals representing the state of process variables to the controllers, and actuators receive output signals from the controllers and take action to affect process variables.

I/O signals may be analog signals or digital signals. Analog I/O signals are variable, in which a voltage or current represents the magnitude of a process parameter such as flow rate or the desired position of a valve. Digital I/O signals represent one of two states: "on/off', "opened/closed", and the like.

Digital signals used in process control are also used to actuate a relay or to count pulses.

Sophisticated industrial processes may use a number of field devices distributed over a wide area for process control. I/O field wiring from the field devices is often brought to a central location for ease of management. The field wiring may extend to sets of terminals of a terminal block contained in a wiring cabinet. A circuit (referred to as an I/O channel herein) includes the set of terminals and includes a conversion circuit that ultimately is connected to the control system. The conversion circuit converts between I/O signals compatible with the field device and a digital data format.

Fixed-mode conversion circuits convert between one type of I/O signal and the digital data format.

Selectable-mode conversion circuits allow different types of field devices to be connected to each set of terminals of the terminal block.

<CIT> "Universal I/O Signal Interposer System", assigned to the applicant and incorporated by reference herein, discloses removable I/O modules referred to as interposers insertable in the I/O channel to process the I/O signals, supply power to field devices, interpose fuses or other ancillaries in the signal path, and other functions.

<FIG> illustrates a field device I/O connector A for connecting a field device to a process control network N. The field device I/O connector is shown attached to the field wires of a field device D and transceives I/O signals to and from the field device. The field device I/O connector includes a base B having a set of terminals T and a removable I/O module M. The base defines a base I/O channel portion Cb. The I/O module includes a module I/O channel portion Cm. When the I/O module is plugged into the base, connector halves of an electrical connector S electrically connect the base I/O channel portion and the module I/O channel portion to form part of an I/O channel C. The I/O channel includes a conversion circuit V that converts between I/O signals compatible with the field device and a digital data format of the process control network. A network port P connects the field device I/O connector to the process control network and sends and receives digital data to and from the network.

<CIT> discloses a removable communication module connected with the internal bus of a field device that may include diagnostic software to gather information about the field device. It further teaches that the diagnostic software is operatively connected to the internal bus of the field device to enable collecting the diagnostic information.

<CIT> discloses replacing a portion of a wired process control network with a wireless portion, having a radio transmitter and radio receiver defining the ends of the wireless portion.

<CIT> discloses an adapter unit that attaches to a non-fieldbus capable field device and connects the non-fieldbus capable field device to a field bus. The adapter unit attaches to a diagnostics/service interface of the field device to transmit diagnostics/service data through the connected fieldbus.

It is desired to provide a field device I/O connector having a removable I/O module module attached to a base wherein the base can provide diagnostic information concerning operation or operating history of the I/O channel associated with the I/O module, the ancillary inserted in the I/O channel by the I/O module, or the field device attached to the I/O channel.

The present invention is defined in the independent claim <NUM>. Disclosed is a field device I/O connector having a removable I/O module that provides diagnostic information concerning operation or operating history of the I/O channel associated with the I/O module, the ancillary inserted in the I/O channel by the I/O module, or the field device attached to the I/O channel.

An embodiment of a field device I/O connector in accordance with this disclosure includes a base and a removable I/O module attached to the base for transmitting I/O signals along an I/O channel. The base includes a set of one or more electrical connectors that connect the base to the field wires of a field device. The set of electrical connectors can be formed in a possible embodiment as a set of one or more terminals that connect the base to the field wires of a field device. The set of electrical connectors can be adapted to conform to the number of field wires of the field device and the desired type of termination of the field wires.

The base defines a base I/O channel portion that includes the set of electrical connectors. The I/O module includes a module I/O channel portion. When the I/O module is attached to the base, the base and I/O module I/O channel portions are electrically connected together and define part of an I/O channel.

The I/O channel includes a conversion circuit. The conversion circuit may be a fixed-mode conversion circuit or a selectable-mode conversion circuit. Examples of selectable-mode conversion circuits that can be adapted for use with the disclosed I/O field device connection include, but are not limited to, those provided by the commercially available ANALOG DEVICES AD74412R or AD74413R signal processing integrated circuit (Analog Devices, Inc. , One Technology Way, Norwood Massachusetts <NUM>-<NUM> USA). The conversion circuit is connected to a network port on the base that transmits digital data between the field device I/O connector and the process control network.

The I/O module enables signal processing of the I/O signal, supplying power to the field device, interposing fuses or other ancillaries in the signal path, and other functions as disclosed in the '<NUM> patent. In other possible embodiments the I/O module can provide pre commission connection to an attached field device for validating the field device installation during construction of the process control network.

When the I/O module is attached to the base, the I/O module and the base also cooperatively define a diagnostic circuit connected to the module I/O channel portion. The diagnostic circuit in embodiments provides diagnostic information concerning operation or operating history of the I/O channel associated with the I/O module, an ancillary inserted in the I/O channel by the I/O module, the field device attached to the I/O channel, or perform some other diagnostic function.

In possible embodiments, the base is configured with multiple sets of electrical connectors to connect to multiple field devices at one time. The multiple sets of electrical connectors in a possible embodiment are formed as a terminal block having multiple sets of terminals for landing field wires of the multiple field devices. Multiple respective base I/O channel portions extend from the sets of terminals of the terminal block. Each base I/O channel portion removably attaches an I/O module to the base to form part of an I/O channel.

The base of the I/O module includes a diagnostic logic circuit that monitors the diagnostic circuit, performs the diagnostic logic to generate diagnostic data, and transmits the diagnostic data output to an output. Having the diagnostic logic circuit in the base enables customization of the diagnostic logic circuit for the specific configuration of the I/O module or the type of field device the I/O module will be attached to.

In other embodiments the diagnostic logic circuit is outside of the I/O module and may be located on the base or remote from the base.

The digital data output from the base in embodiments of the disclosed field device I/O connector includes both digitized I/O signal data from each field device attached to the field device I/O connector and diagnostic data generated from each I/O module attached to the base of the field device I/O connector.

Other objects and features of the disclosure will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing sheets illustrating one or more non-limiting embodiments.

<FIG> illustrates a first embodiment single-field device I/O connector <NUM>. The field device I/O connector includes a base <NUM> having a set of electrical connectors that land the field wires of a field device D. The set of electrical connectors is formed as a terminal block that includes a set of terminals <NUM>. The terminal block can be configured as needed for the number of field wires from the field device and the type of termination desired for the field wires.

Removably mounted on the base <NUM> is an I/O module <NUM>. The terminals of the terminal block <NUM> and the base define a base I/O channel portion 16b. The I/O module includes a module I/O channel portion <NUM>.

When the I/O module is mounted to the base, the base I/O channel portion and the module I/O channel portion are electrically connected together by a pair <NUM> of male and female cooperating electrical connectors (one electrical connector fixedly attached to the I/O module, the other electrical connector fixedly attached to the base). The pair <NUM> of electrical connectors electrically connect the base and module I/O channel portions together to cooperatively define an I/O channel <NUM>.

The I/O channel includes a conversion circuit described in more detail below. The illustrated I/O channel <NUM> is part of a signal processing circuit <NUM> disposed in the base that includes the conversion circuit. In other possible embodiments the I/O channel <NUM> extends away from the base to a conversion circuit not disposed on the base.

A digital data circuit <NUM> extends from the signal processing circuit <NUM> to a network port <NUM>. The digital data circuit and the network port cooperate to transfer digital data from the signal processing circuit out of the field device I/O connector to the process control network and to transfer digital data received from the process control network to the signal processing circuit. The network port is compatible with the physical layer of the process control network and in embodiments may be a jack (for example, an RJ45 jack), a set of terminals, a communications bus, a cable socket, part of a backplane, or the like.

If the conversion circuit is a selectable-mode conversion circuit, the data transferred to the signal processing circuit can include commands to set the operating mode of the conversion circuit as required by the type of field device D.

The illustrated I/O module <NUM> inserts an ancillary formed as a fuse <NUM> in the signal path of the I/O channel <NUM>. The I/O module <NUM> also includes a portion 24A of a diagnostic circuit that is connected to the I/O channel across the fuse. The diagnostic circuit monitors the state of the fuse (fuse open, fuse closed, or the like).

When the I/O module <NUM> is plugged into the base <NUM>, the module diagnostic circuit portion 24A connects with a base diagnostic circuit portion 24B carried in the base through the pair <NUM> of cooperating male and female electrical connectors to define a diagnostic circuit <NUM> operable to monitor the state of the fuse. The diagnostic circuit <NUM> does not affect the signal traveling through the I/O channel <NUM> (much like a voltmeter does not significantly affect the voltage drop of a circuit or an ammeter does not significantly affect current flow through a circuit).

In the illustrated embodiment the diagnostic circuit <NUM> is connected to a diagnostic logic circuit <NUM> forming part of the signal processing circuit <NUM>. The diagnostic logic circuit extracts diagnostic data from the diagnostic circuit and formats the diagnostic data in a digital data format. The diagnostic data is output from the field device I/O connector through the network port <NUM>.

An I/O module like the I/O module M shown in <FIG> that lacks a diagnostic circuit can perform properly when connected to the base <NUM> but would not provide diagnostic data.

<FIG> illustrates a second embodiment single-field device I/O connector <NUM> similar to the field device I/O connector <NUM>. In this embodiment the diagnostic logic circuit <NUM> is carried in the I/O module <NUM>. The module diagnostic circuit portion 24A includes a portion extending from the module I/O channel portion <NUM> to the diagnostic logic circuit <NUM>, and a portion extending from the diagnostic logic circuit for transmitting the diagnostic data extracted by the diagnostic logic circuit out of the I/O module. The base diagnostic circuit portion 24B is configured to receive the diagnostic data from the I/O module and transmit the diagnostic data to the signal processing circuit <NUM> for output through the network port <NUM>.

In both of the embodiments shown in <FIG>, the control system can communicate with the diagnostic logic circuit <NUM> through the network port <NUM> if the signal processing circuit <NUM> and diagnostic logic circuit are configured for two-way communication represented by the double arrow shown in <FIG> and in <FIG>. This enables the control system to change acceptable parameters, reset accumulated values, or otherwise set or modify values stored or used by the diagnostic logic circuit.

<FIG> illustrates a multi-field device I/O connector <NUM> configured to attach the field wires of up to four field devices (not shown) to the connector. Other embodiments of a multi-field device I/O connector may be configured to attach up to two, three, or more than four field devices.

The base <NUM> includes multiple sets of electrical connectors formed as a terminal block having four sets of terminals <NUM> configured to connect the field wires of the field devices to the multi-field I/O connector. The base and the sets of terminals define four like base I/O channel portions 16b. The multi-field device I/O connector carries up to four removable I/O modules <NUM> of the kind described above, each I/O module including a module I/O channel portion <NUM>. The base and the I/O modules form respective I/O channels <NUM> that each include a signal processing circuit <NUM> as previously described with respect to the I/O channel of the single-field device I/O connector.

The four signal processing circuits <NUM> are connected to a common communication circuit <NUM> that handles data transmission between the digital data circuit <NUM> and the signal processing circuits. Each I/O channel is associated with a respective diagnostic circuit <NUM> that monitors the module I/O channel portion as previously described for the single-field device I/O connector. Each diagnostic circuit may include a diagnostic logic circuit formed as part of the signal processing circuit of the I/O channel or in the I/O module as previously described.

In <FIG> each diagnostic circuit <NUM> is connected to the signal processing circuit <NUM> associated with its I/O module. In other embodiments with diagnostic logic circuits disposed in the I/O modules, a diagnostic data output circuit similar to the diagnostic data output circuit <NUM> shown in <FIG> is associated with each I/O module and connects the logic diagnostic circuit in the I/O module with the signal processing circuit.

Yet another possible embodiment of a field device I/O connector <NUM> is shown in <FIG> and is similar to the field device I/O connector <NUM> shown in <FIG>. In this embodiment, however, the diagnostic circuit <NUM> connects to its own separate, dedicated output port <NUM> of the field device I/O connector. The output port in embodiments may be realized as a jack, communications bus, cable socket, or the like and is intended to connect the diagnostic circuit to a diagnostic logic circuit remote from the field device I/O connector.

In <FIG>, a pair of cooperating electrical connectors electrically connect the base <NUM> and an I/O module <NUM>. <FIG> illustrates a portion of a field device I/O connector <NUM> similar to the field device I/O connector <NUM> but has the I/O channel circuit portions connected by a first pair 17a of male and female electrical connectors and the diagnostic circuit portions connected by a second pair 17b of male and female electrical connectors. I/O modules without a diagnostic circuit can include a dummy male or female electrical connector to form the pair 17b of electrical connectors.

Some of the circuits shown in the drawings are drawn as single lines to simplify the drawings and can represent multiple-wire or multiple-line circuit paths as understood in the art.

Claim 1:
A field device I/O connector for connecting a field device to a process control network, the field device I/O connector comprising:
a base (<NUM>) and an I/O module (<NUM>) removably attached to the base;
a set of electrical connectors mounted on the base, the set of electrical connectors being connectable with field wires extending from the field device to carry I/O signals between the field device I/O connector and the field device, the set of electrical connectors comprising one or more electrical connectors;
the set of electrical connectors and the base defining a base I/O channel portion (16b) extending from the set of electrical connectors, and the I/O module comprising a module I/O channel portion (<NUM>), the base I/O channel portion and the module I/O channel portion being electrically connected to one another and together forming an I/O channel (<NUM>) when the I/O module is attached to the base, the base I/O channel portion comprising a conversion circuit (<NUM>) being configured to convert between I/O signals and signals utilizing a digital data format used by the process control network; and
the base comprising a digital data circuit (<NUM>) and a network port (<NUM>), the digital data circuit connected to the base I/O channel portion and being configured to transfer digital data received from the conversion circuit to the network port, the network port being configured to be attachable to the process control network and to transmit data received from the digital data circuit to the process control network when the network port is attached to the process control network;
characterized by
the base and the I/O module cooperatively defining a diagnostic circuit (<NUM>) electrically connected to the module I/O channel portion, the diagnostic circuit being configured to generate diagnostic data concerning the operating state or operational history of the I/O channel, I/O channel circuit components, or the field device attached to the I/O channel when the field device I/O connector is connecting the field device to the process control network;
the diagnostic circuit being connected to a diagnostic logic circuit (<NUM>) being configured to extract the diagnostic data in a digital data format from the diagnostic circuit;
the digital data circuit being connected to the diagnostic logic circuit and being configured to transfer the diagnostic data extracted by the diagnostic logic circuit to the network port; and
the base comprising the diagnostic logic circuit.