Subsea control system including bumpless changeover

Abstract

A subsea control system includes a first logic controller located topside, a first electronics manifold located subsea, and a first cable operable to provide communication between the first logic controller and the first electronics manifold. A second logic controller is located topside, a second electronics manifold is located subsea, and a second cable is operable to provide communication between the second logic controller and the second electronics manifold. A device includes a lead device operably connected to a lead electronics module, a backup device operably connected to a backup electronics module, a lead connector connected to the lead electronics module, and a backup connector connected to the backup electronics module. A third cable provides communication between the first electronics manifold and the lead connector and a fourth cable provides communication between the second electronics manifold and the backup connector. A first communication link is provided between the first logic controller and the second logic controller, and a second communication link is provided between the lead electronics module and the backup electronics module. The first communication link and the second communication link cooperate to facilitate the instantaneous transition between multiple communication modes.

Description

BACKGROUND

[0001] The present invention relates to a subsea control and monitoring system. More specifically, it pertains to a system that integrates topside controllers with submerged sensors, motors, and other devices.

[0002] In subsea operations, such as underwater exploration, oil and gas production, and offshore energy generation it is often desirable to include primary and secondary controllers topside that operate to control or monitor devices such as motors and sensors that are located subsea. Redundant control as well as redundant devices can reduce maintenance and increase system reliability.

[0003] WO 2023 / 039052 A1 describes an apparatus for controlling a subsea blowout preventer (BOP) of a subsea stack assembly installed over a subsea oil and gas well. The control system includes first and second topside control devices as well as first and second subsea control devices, each communicatively connected with the BOP and operable to control its operation. The first and second topside control devices are communicatively connected via a ring communication network, and the subsea control devices form part of respective control pods of the subsea stack assembly.

[0004] US 2021 / 0262312 A1 describes a subsea control system including topside and subsea control equipment configured to control subsea well equipment. The system provides communication between topside and subsea components and includes redundant communication paths to improve reliability. The arrangement facilitates transmission of control data and sensor data between controllers associated with topside and subsea equipment.SUMMARY

[0005] The present invention provides a subsea control system and a method of controlling a subsea device with the features of the independent claims. Further advantageous embodiments are subject matter of the dependent claims.

[0006] In one construction, a subsea control system includes a first logic controller located topside, a first electronics manifold located subsea, and a first cable operable to provide communication between the first logic controller and the first electronics manifold. A second logic controller is located topside, a second electronics manifold is located subsea, and a second cable is operable to provide communication between the second logic controller and the second electronics manifold. A device includes a lead device operably connected to a lead electronics module, a backup device operably connected to a backup electronics module, a lead connector connected to the lead electronics module, and a backup connector connected to the backup electronics module. A third cable provides communication between the first electronics manifold and the lead connector and a fourth cable provides communication between the second electronics manifold and the backup connector. A first communication link is provided between the first logic controller and the second logic controller, and a second communication link is provided between the lead electronics module and the backup electronics module. The first communication link and the second communication link cooperate to facilitate the instantaneous transition between any of a first communication mode in which the first logic controller communicates with the lead device, a second communication mode in which the first logic controller communicates with the backup device, a third communication mode in which the second logic controller communicates with the lead device, and a fourth communication mode in which the second logic controller communicates with the backup device.

[0007] In another construction, a subsea control system includes a first communication channel including a first logic controller located topside, a first electronics manifold located subsea, and a first cable operable to provide communication therebetween and a second communication channel including a second logic controller located topside, a second electronics manifold located subsea, and a second cable operable to provide communication therebetween. A first communication link couples the first logic controller and the second logic controller to provide communication therebetween. Each device of a plurality of devices includes a lead electronics module in communication with a lead device and the first electronics manifold, a backup electronics module in communication with a backup device and the second electronics manifold, and a second communication link coupled to the lead electronics module and the backup electronics module to provide communication therebetween. For each device, the first communication link and the second communication link cooperate to facilitate the instantaneous transition between any of a first communication mode in which the first logic controller communicates with the lead device, a second communication mode in which the first logic controller communicates with the backup device, a third communication mode in which the second logic controller communicates with the lead device, and a fourth communication mode in which the second logic controller communicates with the backup device.

[0008] In another aspect, a method of controlling a subsea device includes connecting a first logic controller and a second logic controller with a first communication link, connecting the first logic controller to a first electronics manifold, and connecting the second logic controller to a second electronics manifold. The method further includes connecting each of a plurality of devices to the first electronics manifold and the second electronics manifold, each of the devices having a lead electronics module connected to a lead device and the first electronics manifold, a backup electronics module connected to a backup device and the second electronics manifold, and a second communication link providing communication between the lead electronics module and the backup electronics module. The method also includes communicating in a first communication mode between the first logic controller and each lead device of the plurality of devices, detecting a communication fault between the first logic controller and a first device of the plurality of devices, and transitioning the communication to the first device instantaneously in response to the detected fault to one of a second communication mode in which the first logic controller communicates with the backup device, a third communication mode in which the second logic controller communicates with the lead device, and a fourth communication mode in which the second logic controller communicates with the backup device.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced. FIG. 1 schematically illustrates an arrangement of a subsea control system. FIG. 2 is a flowchart illustrating a process for operating the subsea control system illustrated in FIG. 1. DETAILED DESCRIPTION

[0010] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in this description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0011] Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0012] It should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms "including," "having," and "comprising," as well as derivatives thereof, mean inclusion without limitation. The singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term "or" is inclusive, meaning and / or, unless the context clearly indicates otherwise. The phrases "associated with" and "associated therewith," as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Furthermore, while multiple embodiments or constructions may be described herein, any features, methods, steps, components, etc. described with regard to one embodiment are equally applicable to other embodiments absent a specific statement to the contrary.

[0013] Also, terms such as "first", "second", "third" and so forth may be used herein to refer to various elements, information, functions, or acts, but should not be considered as limiting in any way. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

[0014] In addition, the term "adjacent to" may mean that an element is relatively near to but not in contact with a further element or that the element is in contact with the further portion unless the context clearly indicates otherwise. Further, the phrase "based on" is intended to mean "based, at least in part, on" unless explicitly stated otherwise. Terms "about" or "substantially" or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standard is available, a variation of twenty percent would fall within the meaning of these terms unless otherwise stated.

[0015] FIG. 1 illustrates a simplified example of a subsea control system 100 that includes a topside control 102 that operates to receive information from various subsea devices 104 such as sensors, motors, valves, and actuators, and that operates to collect information from or to control those devices 104 that are controllable (e.g., motors, actuators, drives, valves, etc.). The topside control 102 is positioned on shore, on a ship or vessel, a platform, or other structure that is located above the sea surface 132. The topside control 102 includes a first logic controller 106 and a second logic controller 108 that is preferably similar to or identical to the first logic controller 106. In one arrangement, programmable-logic controllers are employed with other micro-processor-based controllers also being suitable for use.

[0016] A first communication link 142 is provided between the first logic controller 106 and the second logic controller 108 and operates to allow either of the first logic controller 106 and the second logic controller 108 to take over operation for the other controller should there be a failure or a break in the communication as will be described in greater detail below. Thus, each of the first logic controller 106 and the second logic controller 108 can serve as a redundant backup for the other should this be desired.

[0017] The remainder of the subsea control system 100 is located beneath the sea surface 132 and is therefore referred to herein as "subsea". With continued reference to FIG. 1, the subsea control system 100 includes a first electronics manifold 110, a second electronics manifold 112, and a plurality of devices 104 (two shown). In preferred arrangements, the first electronics manifold 110 and the second electronics manifold 112 are similar or identical to one another such that one can serve as a redundant backup for the other if desired.

[0018] Each of the first electronics manifold 110 and the second electronics manifold 112 includes an input wet-mateable connector 114 that provides for a communication and control connection between the respective first electronics manifold 110 and second electronics manifold 112 and the corresponding first logic controller 106 and second logic controller 108. The input wet-mateable connector 114 for each of the first electronics manifold 110 and the second electronics manifold 112 provides the sole connection between the subsea components and the topside control 102. Of course, other arrangements could include backup connections or additional connections as desired. It should be noted that the term "input" with regard to the input wet-mateable connectors 114 should not be read as limiting the wet-mateable connector 114 to only inputs. Rather, it refers to the position of the wet-mateable connector 114 as the communication link with the topside control 102. It should be understood that input and output signals can pass between the first electronics manifold 110, the second electronics manifold 112, and the topside control 102.

[0019] A first cable 134 provides the connection between the first logic controller 106 and the wet-mateable connector 114 for the first electronics manifold 110. The first cable 134 connects to the first logic controller 106 using any manner desired. However, in the illustrated arrangement, the first cable 134 includes a wet-mateable connector at its second end that is adapted to facilitate a wet-mating connection to the wet-mateable connector 114. The use of the wet-mateable connector 114 for the first cable 134 allows users to make or break connections as desired without having to raise and lower equipment from or into the water.

[0020] A second cable 136 provides the connection between the second logic controller 108 and the wet-mateable connector 114 for the second electronics manifold 112. The second cable 136 is similar to the first cable 134 and connects to the second logic controller 108 using any manner desired. As with the first cable 134, the second cable 136 includes a wet-mateable connector adapted to make a connection with the wet-mateable connector 114 of the second electronics manifold 112.

[0021] As will be discussed in greater detail, the first cable 134 includes a first primary communication channel and a first secondary communication channel and the second cable 136 includes a second primary communication channel and a second secondary communication channel. Each communication channel may include one or more wires or cables including but not limited to Ethernet or fiber optic cables.

[0022] Each of the first electronics manifold 110 and the second electronics manifold 112 also includes a plurality of output wet-mateable connectors 114. Each of the output wet-mateable connectors 114 connects to the input wet-mateable connector 114 to facilitate communication between the output wet-mateable connectors 114 and the topside control 102.

[0023] Each output wet-mateable connector 114 is also connectable to any one of a plurality of devices 104 to allow data and control signals to pass between the devices 104 and the topside control 102. Devices 104 include sensors, controls, motors, actuators, valves, and the like which are often used in subsea applications such as drilling and power transfer operations.

[0024] As with the term "input", the term "output" is used simply to identify the function of the output wet-mateable connectors 114 and should not be interpreted as limiting the communication in any way. Each output wet-mateable connector 114 can facilitate communication to or from the device 104 to which the output wet-mateable connector 114 is connected.

[0025] A third cable 138 includes a wet-mateable connector on both ends to facilitate its attachment to one of the devices 104 at one end and one of the output wet-mateable connectors 114 of the first electronics manifold 110 at the opposite end. A fourth cable 140, which is substantially the same as the third cable 138 includes wet-mateable connectors on both ends with one connected to one of the output wet-mateable connectors 114 of the second electronics manifold 112 and the other connected to one of the devices 104. As illustrated in the arrangement of FIG. 1, which illustrates two devices 104, a third cable 138 connects to each of the devices 104 and a fourth cable 140 also connects to each of the devices 104 such that each device 104 is connected to each of the first electronics manifold 110 and the second electronics manifold 112.

[0026] Each device 104 includes a housing that supports or contains a lead connector 118, a backup connector 120, a lead electronics module 122, a backup electronics module 124, a lead device 126, and a backup device 128. The lead connector 118 is a wet-mateable connector arranged to connect to the third cable 138 and to the first electronics manifold 110. The backup connector 120 is a wet-mateable connector arranged to connect to the fourth cable 140 and to the second electronics manifold 112.

[0027] The lead electronics module 122 and the backup electronics module 124 are substantially the same as one another and include any electronics, processors, signal conditioning, and the like needed to operate or communicate with the particular lead device 126 and backup device 128. The lead electronics module 122 is connected to the lead connector 118 and the backup electronics module 124 is connected to the backup connector 120. A second communication link 144 is provided between the lead electronics module 122 and the backup electronics module 124 to facilitate communication therebetween as will be described in greater detail.

[0028] The lead device 126 connects to the lead electronics module 122 and operates to collect data, control a process, or act in any other manner necessary. The backup device 128 operates as a backup to the lead device 126 and as such may be identical to the lead device 126. However, different devices 104 may require variations between the lead device 126 and the backup device 128. For example, in the illustrated construction, one of the devices 104 is a sensor 116 and includes a backup device 128 that is substantially the same as the lead device 126. However, the second device 104 is a motor 130. In this arrangement, a single motor is provided with two windings. A first winding operates as the lead device 126 and operates the motor. A second winding operates as the backup device 128 and is also capable of operating the motor 130. The two windings may or may not be identical to one another.

[0029] FIG. 2 illustrates a process 200 for controlling a subsea control system 100 as illustrated in FIG. 1. In the process 200, a first connection step 202 connects the first logic controller 106 and the second logic controller 108 with the first communication link 142. A second connection step 204 connects the first logic controller 106 with the first electronics manifold 110 and a third connection step 206 connects the second logic controller 108 with the second electronics manifold 112.

[0030] A fourth connection step 208 connects each of a plurality of devices 104 to the first electronics manifold 110 and the second electronics manifold 112 and provides a second communication link 144 between the lead electronics module 122 and the backup electronics module 124.

[0031] A communication step 210 establishes a first communication mode in which the first logic controller 106 communicates with the lead device 126 of each of the plurality of devices 104. A detection step 212 detects a communication fault between the first logic controller 106 and a first device of the plurality of devices 104. The communication fault can be the result of any breakdown in communication, or operation (e.g., a device 104 in the form of a valve fails to move) between the lead device 126 and the first logic controller 106 at any point along the communication link therebetween.

[0032] A transition step 214 occurs in response to the detection step 212 detecting a fault in the first device 104 or in the communication between the first device 104 and the first logic controller 106. In the transition step 214, the communication to the first device 104 instantaneously transitions to one of a second communication mode in which the first logic controller 106 communicates with the backup device 128, a third communication mode in which the second logic controller 108 communicates with the lead device 126, and a fourth communication mode in which the second logic controller 108 communicates with the backup device 128.

[0033] As used herein, the terms "instantaneous", "instantaneous transition", or the like mean that the switch between communication modes occurs automatically, without user intervention and that the transition does not require any systems or devices to reset, restart, or operate in any manner that would indicate that a transition has occurred. Thus, the system provides a "bumpless" or "seamless" transition between the various communication and operating modes.

[0034] With reference to FIG. 1 a more detailed description of the operation will be provided. The initial set-up of the subsea control system 100 includes positioning the topside control 102 including the first logic controller 106 and the second logic controller 108 at a topside location. The remaining components including the first electronics manifold 110, the second electronics manifold 112, and the plurality of devices 104 are positioned subsea. The first cable 134 connects the first electronics manifold 110 to the first logic controller 106 and the second cable 136 connects the second electronics manifold 112 and the second logic controller 108. Each third cable 138 of the plurality of third cables 138 connects one of the devices 104 to one of the output wet-mateable connectors 114 of the first electronics manifold 110. Each fourth cable 140 of the plurality of fourth cables 140 connects one of the devices 104 to one of the output wet-mateable connectors 114 of the second electronics manifold 112. In this arrangement, each device 104 includes a third cable 138 connected to the lead connector 118 and a fourth cable 140 connected to the backup connector 120.

[0035] As discussed, it is preferable to include wet-mateable connectors for all subsea connections so that connections can be made or broken without having to pull any components from the water.

[0036] It should be noted that the following will describe examples of communication and control modes from the topside control 102 to the devices 104. However, it is important to note that communication in the opposite direction is possible and, in most cases, expected. For clarity, only one direction is described.

[0037] In a first communication mode, the first logic controller 106 communicates with the lead device 126 via a first primary communication channel. The first primary communication channel extends from the first logic controller 106 to the first electronics manifold 110 via the first cable 134. From the first electronics manifold 110, the first primary communication channel continues to the lead connector 118 via the third cable 138. From the lead connector 118, the first primary communication channel extends to the lead electronics module 122 via a cable or other connection depending upon the arrangement of the device 104 and from the lead electronics module 122 to the lead device 126.

[0038] During operation, the subsea control system 100 may detect that communication between the lead device 126 and the first logic controller 106 has failed or been interrupted. In this case, the subsea control system 100 may transition to a second communication mode in which the first logic controller 106 communicates with the lead device 126 via a first secondary communication channel. The first secondary communication channel extends from the first logic controller 106 to the first electronics manifold 110 via the first cable 134. From the first electronics manifold 110, the first secondary communication channel continues to the lead connector 118 via the third cable 138. From the lead connector 118, the first secondary communication channel extends to the lead electronics module 122 via a cable or other connection depending upon the arrangement of the device 104 and from the lead electronics module 122 to the lead device 126. As described, the first cable 134 and the third cable 138 include portions of both the first primary communication channel and the first secondary communication channel. In addition, in arrangements in which the connection between the lead connector 118 and the lead electronics module 122 is made using a cable, a single cable containing both channels or two separate cables may be employed. As should be clear, both the first primary communication channel and the first secondary communication channel do not utilize the first communication link 142 or the second communication link 144 to complete the communication. However, both of the first communication link 142 and the second communication link 144 remain active to facilitate transitions to other communication modes as will be described.

[0039] The subsea control system 100 may also transition to a third communication mode in which the second logic controller 108 takes over communication from the first logic controller 106. The first communication link 142 allows the data or necessary information from the first logic controller 106 to be transferred to the second logic controller 108 so that the second logic controller 108 can seamlessly take control. In some situations, the first logic controller 106 continues to communicate but does so by communicating with the second logic controller 108 via the first communication link 142.

[0040] In the third communication mode, the second logic controller 108 communicates with the backup electronics module 124 via a second primary communication channel. The second primary communication channel extends from the second logic controller 108 to the second electronics manifold 112 via the second cable 136. From the second electronics manifold 112, the second primary communication channel continues to the backup connector 120 via the fourth cable 140. From the backup connector 120, the second primary communication channel extends to the backup electronics module 124 via a cable or other connection depending upon the arrangement of the device 104. From the backup electronics module 124 the second primary communication channel can extend through the lead electronics module 122 to the lead device 126 or can extend from the backup electronics module 124 to the backup device 128.

[0041] In a fourth communication mode, the second logic controller 108, or the first logic controller 106 through the first communication link 142 and the second logic controller 108 communicates with the backup electronics module 124 via a second secondary communication channel. The second secondary communication channel extends from the second logic controller 108 to the second electronics manifold 112 through the second cable 136. From the second electronics manifold 112, the second secondary communication channel extends to the backup connector 120 through the fourth cable 140. The second secondary communication channel then extends from the backup connector 120 to the backup electronics module 124. From the backup electronics module 124, the second secondary communication channel can extend through the lead electronics module 122 to the lead device 126 or can extend from the backup electronics module 124 to the backup device 128. As described, the second cable 136 and the fourth cable 140 include portions of both the second primary communication channel and the second secondary communication channel. In addition, in arrangements in which the connection between the backup connector 120 and the backup electronics module 124 is made using a cable, a single cable containing both channels or two separate cables may be employed. As should be clear, both the second primary communication channel and the second secondary communication channel may or may not utilize the first communication link 142 or the second communication link 144 to complete the communication. However, both of the first communication link 142 and the second communication link 144 remain active to facilitate transitions to other communication modes.

[0042] It should be understood that other communication modes or paths may be possible with the present arrangement. For example, the first communication link 142 and / or the second communication link 144 can be used to bridge across different communication links such that the first logic controller 106 becomes part of the second primary communication channel or the second secondary communication channel using the second logic controller 108 simply as a bridge. Similarly, the second communication link 144 can be used to allow the first primary communication channel or the first secondary communication channel to communicate with the backup device 128 by using the second communication link 144 and the backup electronics module 124 as bridges. Thus, each of the first logic controller 106 and the second logic controller 108 can operate to control either of the lead device 126 and the backup device 128 using seamless and instantaneous transitions between the various communication and control paths.

[0043] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be included in the claim scope: the scope of patented subject matter is defined only by the allowed claims. Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.

Claims

1. A subsea control system (100) comprising: a first logic controller (106) located topside; a first electronics manifold (110) located subsea; a first cable (134) operable to provide communication between the first logic controller (106) and the first electronics manifold; a second logic controller (108) located topside; a second electronics manifold (112) located subsea; a second cable (136) operable to provide communication between the second logic controller (108) and the second electronics manifold (112); a device (104) including: a lead device (126) operably connected to a lead electronics module (122); a backup device (128) operably connected to a backup electronics module (124); a lead connector (118) connected to the lead electronics module (122); and a backup connector (120) connected to the backup electronics module (124); a third cable (138) operable to provide communication between the first electronics manifold (110) and the lead connector (118); a fourth cable (140) operable to provide communication between the second electronics manifold (112) and the backup connector (120); wherein the lead connector (118) is connected to the first electronics manifold (110) via the third cable (138) and the backup connector (120) is connected to the second electronics manifold (112) via the fourth cable (140) such that the device (104) is connected to both the first electronics manifold (110) and the second electronics manifold (112); a first communication link (142) extending between and connecting the first logic controller (106) and the second logic controller (108); and a second communication link (144) extending between and connecting the lead electronics module (122) and the backup electronics module (124), wherein each of the first electronics manifold (110) and the second electronics manifold (112) comprises a plurality of device connectors configured for connection to a respective plurality of devices (104); the first communication link (142) and the second communication link (144) cooperating to facilitate an instantaneous transition between any of a first communication mode in which the first logic controller (106) communicates with the lead device (126), a second communication mode in which the first logic controller (106) communicates with the backup device (128), a third communication mode in which the second logic controller (108) communicates with the lead device (126), and a fourth communication mode in which the second logic controller (108) communicates with the backup device (128).

2. The subsea control system (100) of claim 1, wherein each of the first communication link (142) and the second communication link (144) includes a first communication path and a second communication path.

3. The subsea control system (100) according to any of the preceding claims, wherein the first cable (134) includes a first primary communication channel that provides communication between the first logic controller (106) and the first electronics manifold (110) and a first secondary communication channel that provides communication between the second logic controller (108) and the first electronics manifold (110), and wherein the second cable (136) includes a second primary communication channel that provides communication between the second logic controller (108) and the second electronics manifold (112) and a second secondary communication channel that provides communication between the first logic controller (106) and the second electronics manifold (112).

4. The subsea control system (100) of claim 3, wherein the third cable (138) includes a third primary communication channel that provides communication between the lead electronics module (122) and the first primary communication channel and a third secondary communication channel that provides communication between the lead electronics module (122) and the first secondary communication channel.

5. The subsea control system (100) according to any of the preceding claims, wherein the first electronics manifold (110) includes a topside wet-mateable connector adapted to connect to the first cable (134) to complete the connection between the first logic controller (106) and the first electronics manifold (110), wherein the first electronics manifold (110) in particular includes a plurality of wet-mateable device connectors, a first of the wet-mateable device connectors adapted to connect to the third cable (138) to complete the connection between the first electronics manifold (110) and the lead electronics module (122) of the device (104).

6. The subsea control system (100) according to any of the preceding claims, wherein the device (104) is a sensor that is operable to measure a parameter and transmit that measured data to one of the first logic controller (106) and the second logic controller (108).

7. The subsea control system (100) according to any of the preceding claims, wherein the device (104) is a motor, and wherein the motor includes a primary winding that operates as the lead device (126) and a secondary winding that operates as the backup device (128).

8. The subsea control system (100) according to any of the preceding claims, wherein the device (104) includes a device housing that contains the lead device (126), the backup device (128), the lead electronics module (122), and the backup electronics module (124), and wherein the device housing supports a first wet-mateable connector adapted to connect to the third cable (138) and a second wet-mateable connector adapted to connect to the fourth cable (140).

9. A method of controlling a subsea device, in particular a subsea device of a subsea control system (100) according to any of the preceding claims, the method comprising: connecting a first logic controller (106) and a second logic controller (108) with a first communication link (142) extending between and connecting the first logic controller (106) and the second logic controller (108); connecting the first logic controller (106) to a first electronics manifold (110); connecting the second logic controller (108) to a second electronics manifold (112); connecting each of a plurality of devices (104) to the first electronics manifold (110) and the second electronics manifold (112), each of the devices (104) having - a lead electronics module (122) connected to a lead device (126) and the first electronics manifold (110), - a backup electronics module (124) connected to a backup device (128) and the second electronics manifold (112), and - a second communication link (144) extending between and connecting the lead electronics module (122) and the backup electronics module (124); wherein each of the first electronics manifold (110) and the second electronics manifold (112) comprises a plurality of device connectors configured for connection to a respective plurality of devices (104); communicating in a first communication mode between the first logic controller (106) and each lead device (126) of the plurality of devices (104); detecting a communication fault between the first logic controller (106) and a first device of the plurality of devices; and transitioning the communication to the first device instantaneously in response to the detected fault to one of a second communication mode in which the first logic controller (106) communicates with the backup device (128), a third communication mode in which the second logic controller (108) communicates with the lead device (126), and a fourth communication mode in which the second logic controller (108) communicates with the backup device (128).

10. The method of claim 9, further comprising wet-mateably connecting each device (104) to the first electronics manifold (110) and the second electronics manifold (112).

Images