An I / O switch device

Abstract

There is provided an I / O switch device (6) comprising an Ethernet switch (3), a plurality of plugin module sockets (7) having conductive terminals (11, 12), and one or more internal busses (4a, 4b) for conveying both power and data from the Ethernet switch (3) to the conductive terminals (11,12) The Ethernet switch comprises at least one powered single-pair Ethernet trunk port (1), at least one powered single-pair Ethernet spur port (2), and an isolator (18) between the at least one trunk port and the at least one spur port. The isolator (18) provides galvanic isolation of power and data between a non-intrinsically safe side (18a) of the Ethernet switch having the at least one powered single-pair Ethernet trunk port (1) and an intrinsically safe side (18b) of the Ethernet switch having the at least one powered single pair Ethernet spur port (2). The Ethernet Switch (3) further comprises a power supply (21) that is configured to power the Ethernet switch and the one or more internal busses (4a, 4b) from the at least one powered single-pair Ethernet trunk port (1).

Description

[0001] AN I / O SWITCH DEVICE

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to an I / O switch device, specifically for use with powered single-pair Ethernet networks, for example Ethernet-APL.

[0004] BACKGROUND OF THE INVENTION

[0005] Currently available powered single-pair Ethernet-APL field switches are specifically designed to connect Ethernet-APL field devices. However, for any existing process plant (brown field) or a new process plant (green field), the instrumentation for control and monitoring, including emergency shutdown / alarm, will not all be Ethernet-APL compatible or cannot be made Ethernet-APL compatible. Therefore, to incorporate these non-Ethernet-APL-compatible devices / instruments into a control system or SIS (Safety Instrumented System), further expensive I / O (Input / Output) systems must be included alongside the current Ethernet-APL solutions.

[0006] The simplest approach is to traditionally, discretely cable each non-Ethernet- APL device; however, the cabling will be expensive, bulky, and less reliable. Furthermore, discrete cabling requires additional I / O systems in the control room or local equipment room. A more complex scenario is where some plants will require Intrinsically Safe devices for hazardous areas, meaning added barrier hardware and segregated cable design, management, and a different maintenance approach will be required. The cabling expense is increased because in most cases, non- Ethernet-APL devices e.g. Digital or 4-20mA are, or will be, loosely scattered (stratified) around the process plant and not conveniently clustered.

[0007] Solving this with classic remote I / O would cost significantly more, due to the requirement to provide power to the systems, the high enclosure and hardware costs, the need to implement repeaters (or optical fibre) for long-reach Ethernet communication, and to only be able to connect to a limited number of localised devices, where the I / O count per supporting I / O system’s ratio will be unacceptably low. Therefore, classic remote I / O would be an impractical solution due to its high cost, low speed and overall complexity.

[0008] Classic remote I / O solutions also implement a slow I / O internal digital bus, for example HART IP or RS485, which interfaces and uplinks into high-speed Ethernet networks e.g. into PROFINET. This internal bus, required to carry multiple digitized analogue device control loops and measurements, as well as additional serial I / O data, is at a low communication speed. This makes the operation of a highspeed communication device, such as for example an Ethernet-APL device, impossible through a classic remote I / O system.

[0009] Furthermore, for hazardous areas both remote I / O and a dedicated Ethernet- APL based remote I / O will either need separate expensive Ex certified enclosures, from the Ethernet-APL switch enclosures, or use one larger and more expensive Ex enclosure, which may require certification for each different application / population design. In short, remote I / O or an Ethernet-APL based remote I / O can only be effective / efficient for high density clusters of similar I / O types, positioned close to the I / O, and where there are no Ethernet-APL devices present within the same location. This is unlikely to be the case with the uptake of Ethernet-APL technology or as process plants migrate / upgrade over to Ethernet- APL technology.

[0010] It is therefore an object of the invention to improve upon the known art.

[0011] SUMMARY OF THE INVENTION

[0012] According to a first aspect of the invention, there is provided an I / O switch device comprising an Ethernet switch, a plurality of plugin module sockets having conductive terminals, and one or more internal busses for conveying both power and data from the Ethernet switch to the conductive terminals. The Ethernet switch comprises at least one powered single-pair Ethernet trunk port, at least one powered single-pair Ethernet spur port, and an isolator between the at least one trunk port and the at least one spur port. The isolator provides galvanic isolation of power and data between a non-intrinsically safe side of the Ethernet switch having the at least one powered single-pair Ethernet trunk port and an intrinsically safe side of the Ethernet switch having the at least one powered single-pair Ethernet spur port. The isolator may provide capacitive, magnetic and / or optical isolation, for example in accordance with IEC60079 Part 11 :2023. The Ethernet spur ports can be used to provide powered single-pair Ethernet connections to devices / instruments in hazardous areas, for example areas such as oil rigs where electrical equipment has to be power limited to avoid any sparks in the event of a failure. The Ethernet spur ports may also support the connection of Profibus PA devices.

[0013] The Ethernet switch further comprises a power supply that is configured to power the Ethernet switch and the one or more internal busses from the at least one powered single-pair Ethernet trunk port, and so the I / O switch device may not require any separate power input but may be powered solely from the trunk port(s). The internal buses may be powered busses for powering any connected devices / instrumentation, and so power for all the connected devices / instrumentation may also be supplied from the powered single-pair Ethernet trunk port, via the power supply and the internal busses.

[0014] In accordance with a second aspect of the invention, there is provided an I / O switch system comprising the I / O switch device of the first aspect and a plugin module that has been physically plugged into one of the plugin module sockets to connect to the conductive terminals. The plugin module comprises one or more I / O port connectors for connecting I / O devices via respective cables.

[0015] Thus, the plugin module sockets and plugin modules allow interfacing of the single-pair Ethernet trunk cables to non-Ethernet-APL devices, for example HART, 4-20 mA, Foundation Fieldbus, Profibus, Thermocouple, RTDs, strain gauge, Voltage, digital I / O (switches and semiconductors), Modbus and so on.

[0016] The plugin module sockets are connected to the Ethernet switch via the internal busses, the internal busses for example including a non-intrinsically safe power and data bus connected from the non-intrinsically safe side of the Ethernet switch to a non-intrinsically safe one of the plugin module sockets, and / or an intrinsically safe power and data bus connected from the intrinsically safe side of the Ethernet switch to an intrinsically safe one of the plugin module sockets. Therefore the I / O switch device may provide support for both non-intrinsically safe and intrinsically safe devices.

[0017] The intrinsically safe side of the Ethernet switch may comprise power limitation circuitry between the isolator and one or more of the spur ports, and / or between the isolator and one or more of the internal busses. The power limitation circuitry may comprise a voltage clamp and / or a current limiter, to restrict the power that can be delivered and so meet intrinsic safety requirements.

[0018] The internal busses may be high-speed data buses of at least 10 Mbps, or at least 100 Mbps, so that data from high-speed devices can be effectively transferred from the plugin module sockets to the Ethernet switch. The Ethernet switch may comprise a CPU connected to each internal bus, and an Ethernet controller / manager to control the switching performed by the Ethernet switch. The CPU(s) may be integral with the Ethernet controller / manager.

[0019] The non-intrinsically safe and intrinsically safe sides of the Ethernet switch and the isolator may all be formed on a single circuit board of the I / O switch device, to provide a compact switch device that can be easily manufactured.

[0020] The plugin module may comprise a controller for receiving data from at least one of the I / O port connectors in accordance with a first communication protocol and sending data to the Ethernet switch via the conductive terminals in accordance with a second communication protocol that is different to the first communication protocol. The second communication protocol, corresponding to that of the internal bus the plugin module communicates over, may for example be SPI, I2C or Parallel or Ethernet.

[0021] The first communication protocol is the communication protocol that is used by the device, and may for example be serial / parallel or analogue / digital depending on the particular device. The plugin modules may interface with many different types of non-Ethernet-APL devices, for example including HART, 4-20 mA, Foundation Fieldbus, Profibus, Thermocouple, RTDs, strain gauge, Voltage, digital I / O (switches and semiconductors), RS485 Modbus and so on. Optionally, the plugin module may comprise a wireless antenna for implementing a wireless connection to a device.

[0022] The controller of the plugin module may comprise a processor that is configured to process data received from at least one of the I / O port connectors before sending the data to the Ethernet switch. The processor may be remotely programmable via the Ethernet switch to define how the data is to be processed, for example to perform autonomous monitoring / recording, loop control, interlocks or emergency functions, including shutdown, should a failure occur through the system at any point. The controller of the plugin module may be powered solely by power that is drawn from the internal bus connected to the conductive terminals, and so the plugin module may not require any separate power supply.

[0023] The plugin module may comprise an isolator providing galvanic isolation between the conductive terminals and at least a first one of the I / O port connectors, so that the I / O port connector(s) can be connected to devices in hazardous areas. The plugin module may also comprise power limitation circuitry connected between the conductive terminals and one or more of the I / O port connectors, to meet intrinsic safety requirements. The power limitation circuitry may for example comprise a voltage clamp, a current limiter, or a voltage clamp and a current limiter.

[0024] Thus, there is reduction in the number of components required to fulfil the same typical functionality as a remote process I / O system and an Ethernet-APL Switch, comprising one or more Ethernet-APL Trunks and one or more Ethernet- APL 2-WISE / FISCO compatible Spurs, and the process I / O variables may be transmitted / received at a higher speed, by using a fast internal bus to transmit / receive the process I / O variable data from the plugin modules.

[0025] The plugin modules may be configurable, scalable, I / O type compliant pluggable process I / O modules, for communicating with the Ethernet switch, and for the Ethernet switch to efficiently map the process I / O variable’s data into each Ethernet telegram, along with the data to / from any connected Ethernet devices. The size of this solution may be comparably smaller and more compact, as well as comparably less expensive to produce, and the trunk ports may transmit / receive a higher comparable bit-rate density for the process data, for a given system bit-rate of 10 Mbps or 100 Mbps. The plugin modules may be plugged into the plugin module sockets to connect them to the internal busses, if and when required to provide connections to various devices / instrumentation.

[0026] DETAILED DESCRIPTION

[0027] Embodiments of the invention will now be described by way of non-limiting example only and with reference to the accompanying drawings, in which:

[0028] Fig. 1 shows a schematic diagram of an I / O switch system according to an embodiment of the invention;

[0029] Fig. 2 shows a functional block diagram of the I / O switch system of Fig. 1 ;

[0030] Fig. 3 shows a schematic diagram of a plugin module forming part of the I / O switch system of Fig. 1 ; and

[0031] Figs. 4a to 4e show schematic diagrams of further plugin modules that could be implemented instead or in addition to the plugin module of Fig. 3.

[0032] The figures are not to scale, and same or similar reference signs denote same or similar features.

[0033] Fig. 1 shows an I / O switch system comprising an I / O switch device 6 in accordance with an embodiment of the invention. The I / O switch device 6 may comprise an Ethernet switch 3, a plurality (in this case two) of plugin module sockets 7, and internal busses 4a and 4b connected from the Ethernet switch 3 to the plugin module sockets 7. The Ethernet switch 3 comprises at least one (in this case two) powered single-pair Ethernet trunk ports 1 , at least one (in this case three) powered single-pair Ethernet spur ports 17, and an isolator 18 between the trunk and spur ports 1 and 17.

[0034] The isolator 18 delimits a non-intrinsically safe side 18a of the Ethernet switch 3 from an intrinsically safe side 18b of the Ethernet switch 3, and provides galvanic isolation of power and data between those sides of the switch for the purpose of intrinsic safety. The isolator 18 may include capacitive and / or optical isolation, for example in accordance with IEC60079 Part 11 :2023. The galvanic isolation means the intrinsically safe side of the Ethernet switch, for example the spur ports 17, will not be able to draw excessive power from the non-intrinsically safe side of the Ethernet switch, for example the trunk ports 1 , and so the spur ports 17 can be connected to devices 2 in hazardous areas where electrical sparks are not permitted.

[0035] One or more of the Ethernet spur ports 17 may also be power limited by power limitation circuitry 19a at the intrinsically safe side 18b. The power limitation circuity 19a may be a current limiter and / or a voltage clamp, to further ensure that insufficient electrical power for sparking to occur is supplied to the spur port.

[0036] The Ethernet switch 3 may comprise a circuit board 3a on which the non- intrinsically safe and intrinsically safe sides 18a, 18b of the Ethernet switch and the isolator 18 are formed.

[0037] The internal bus 4a may be an intrinsically safe power and data bus connected to the intrinsically safe side 18b of the Ethernet switch 3. Optionally, the internal bus 4a may be connected to power limitation circuitry 19b of the intrinsically safe side 18b of the Ethernet switch. The power limitation circuity 19b may be a current limiter and / or a voltage clamp, to ensure that insufficient electrical power for sparking to occur is supplied to the plugin module socket 7 that the internal bus 4a is connected to. The internal bus 4b may be a non-intrinsically safe power and data bus connected to the non-intrinsically safe side of the Ethernet switch 3, and so may have the ability to supply higher levels of power to the plugin module socket(s) 7 that it is connected to.

[0038] The Ethernet switch 3 may comprise a CPU 22 and an Ethernet controller / manager 23 to control the switching performed by the Ethernet switch. The Ethernet switch 3 also comprises a power supply 21 that provides power to the Ethernet switch, including the CPU 22, Ethernet controller / manager 23 and the internal busses 4a and 4b from the trunk port(s) 1 . Thus, the Ethernet switch does not require any separate source of power and may be powered solely from the trunk port(s) 1 via the power supply 21 .

[0039] Each plugin module socket 7 may comprise one or more AC and / or DC conductive power terminals 11 for supplying power from the internal bus 4a or 4b to a plugin module, and may comprise conductive data terminals 12 for conveying data between the internal bus 4a or 4b and the plugin module.

[0040] Whilst the embodiment of Fig 1 has two internal busses 4a and 4b, one intrinsically safe and one not, in alternative embodiments one or more than two internal busses may be implemented. These may all be intrinsically safe, may all be non-intrinsically safe, or may be a mixture of intrinsically safe and non-intrinsically safe busses. Each internal bus may be connected to the conductive terminals of one or more plugin module sockets.

[0041] The intrinsically safe bus 4a may be IS Isolated by the isolator 18, with the option of additional IS voltage clamping and / or current limiting if the power limitation circuitry 19b is implemented. In some cases current limiting may not be practical due to the power demand of the plugin modules.

[0042] The internal busses 4a and 4b may be high-speed busses capable of transferring data at speeds of at least 10Mbps, to accommodate the requirements of high-speed devices / instruments connected to the system.

[0043] The I / O switch system further comprises at least one removable plugin module that has been physically plugged into one of the plugin module sockets. The example of Fig. 1 includes two plugin modules 7a and 7b that have been plugged into the two plugin module sockets 7, and which connect to the conductive terminals 11 and 12. A variety of different connector configurations may be used to connect and secure each plugin module in the corresponding plugin module socket, for example using latches and / or friction.

[0044] The plugin modules 7a and 7b may comprise I / O port connectors for connecting to devices / instruments 5b and 5a respectively. The schematic diagram of Fig. 2 shows a functional block diagram of the I / O switch system 6. The trunk Ethernet port 1 a may be connected to an Ethernet APL trunk cable for receiving power and conveying data, and the trunk Ethernet port 1 b may be connected to another Ethernet APL trunk cable to a further switch system. The intrinsically safe spur ports 17 may be connected to Ethernet APL spur cables that connect to the Ethernet APL devices 2.

[0045] The intrinsically safe internal bus 4a may be a proprietary high-speed bus type, and be connected to the CPU 22 of the Ethernet switch 3, and the non- intrinsically safe internal bus 4b may be a type of Ethernet bus and connect to an Ethernet port of the Ethernet switch 3. The CPU 22 may provide for data transfer between the protocols of the proprietary bus 4a and the Ethernet protocol. Accordingly, data from the devices 5a or 5b on the high-speed internal busses 4a or 4b can be virtually ‘switched’ through to the trunk ports 1 and the spur ports 17, as if the devices 5a or 5b were one or more Ethernet APL devices.

[0046] The data from the proprietary high speed internal bus 4a may be seamlessly mapped into the Ethernet APL telegram and transmitted via the Ethernet-APL trunk 1 a. The data from the Ethernet bus 4b can also be seamlessly mapped into the Ethernet APL telegram. The proprietary and / or Ethernet internal buses 4a and 4b may communicate with the plugin modules 7a and 7b, which in turn, interface with Classic Process I / O and / or Classic Serial Data busses e.g. RS485 Modbus. Ethernet-APL devices may be attached to one or more of the Ethernet-APL spurs ports 17, and the data from these may be mapped into the APL telegram accordingly.

[0047] The schematic diagram of Fig. 3 shows a block diagram of the plugin module 7a, including the connections to the conductive terminals 11 and 12 of the plugin module socket 7. The plugin module 7a may comprise one or more I / O port connectors 15 with terminals 16 for connecting to cables, the cables connected to the devices / instrumentation 5b (see Fig. 1 ). In some implementations the plugin module 7a may also comprise a wireless antenna 40 for wirelessly connecting to further devices / instrumentation. The plugin module 7a may comprise a controller 13 for receiving data from the I / O port connectors, and may perform protocol conversion between the protocol used by the devices / instrumentation 5b and the Ethernet protocol used by the internal bus 4b. Thus, the device / instrumentation 5b may appear to the Ethernet switch 3 to be the same as an Ethernet-APL device / instrument.

[0048] The controller 13 may process the data received from the devices 5b before sending data on to the internal bus 4b, via the conductive data terminals 12. This processing may for example be pre-programmed into the plugin module 7a, and / or the controller may be programmable via the internal bus 4b to define how the controller 13 is to process the data received from the devices 5b. For example, the controller 13 may perform data logging and / or data analysis, or run processing software / apps.

[0049] The controller 13 may comprise software / firmware, and include non-volatile memory which could be programmed to perform autonomous monitoring / recording, loop control, interlocks or emergency functions, including shutdown, should a failure occur through the system at any point. This local control feature could be managed remotely by the main control system when in normal operation. For example, set points and PID control algorithms can be adjusted remotely, therefore making the plugin module semi-autonomous. Control software may also or alternatively reside at the CPU 22 and / or Ethernet controller / manager 23.

[0050] The controller 13 may comprise one or more high-speed Analogue to Digital converters that receive signals from the devices 5b and digitise them at high bit resolution for sending on to the internal bus 4b. Thus, each internal bus may be of a speed that is able to collect high bit resolution data from each of the plugin modules connected to it in sequence.

[0051] The plugin module 7a may comprise transmitters and / or receivers 14 in accordance with the physical layer specifications of the I / O port connectors 15, for sending and / or receiving data between the devices / instrumentation 5b and the controller 13. The controller 13 may be able to adjust the settings of the transmitters and / or receivers 14 via the control line 9.

[0052] The transmitters and / or receivers 14 and the controller 13 may be powered directly from the conductive power terminals 11 . Alternatively, as shown in Fig. 3 the plugin module 7a may comprise one or more power supplies 10, which draw power from the conductive power terminals 11 , and supply power to the transmitters and / or receivers 14 and the controller 13. The power supplies 10 may be intrinsically or non-intrinsically safe, DC-DC or AC-DC convertors that may be used to power the various systems on the plugin module.

[0053] The transmitters and / or receivers 14 may comprise intrinsically safe voltage clamping or current limiting circuitry, which may for example comply with IEC60079 Part 11 , Edition 7 and / or Part 47 and / or Part 7. Different plugin modules plugged into different plugin module sockets 7 may be used to electrically and physically segregate Part 7 components from Part 11 / 47 circuits.

[0054] A variety of different plugin modules may be plugged into the plugin module sockets depending on the intrinsic safety requirements of the devices / instrumentation 5a and 5b and whether the plugin module socket that is to receive the plugin module is intrinsically safe or not. The plugin modules will have, or will need, optional / different components, or different protection approaches / configurations, depending on if the intrinsically safe bus 4a or non- intrinsically safe bus 4b, or both busses are used. Then intrinsically safe and non- intrinsically safe devices / instruments can be interfaced to the I / O switch device 6, via the plugin modules. For example, Figs. 4a to 4e illustrate various configurations of plugin modules to meet various device / instrumentation requirements.

[0055] The plugin module of Fig. 4a may allow intrinsically safe devices / instrumentation to be connected to the non-intrinsically safe bus 4b. Specifically, the plugin module may comprise an isolator 25a and power limitation circuitry 26a that are placed between the non-intrinsically safe bus 4b and the I / O port connectors 15a. The isolator 25a may provide galvanic isolation of power and data between the I / O port connectors 15a and the non-intrinsically safe bus 4b, and power limitation circuitry 26a may clamp the voltage and limit the current delivered to the I / O port connectors 15a, thus making the I / O port connectors 15a suitable for connecting to devices in hazardous areas. The isolator 25a may also isolate the plugins module’s power supply from the non-intrinsically safe bus 4b, so that both the power and the communications are isolated from the non-IS trunk ports 1 , allowing the plugin module and connected devices / instrumentation to be isolated and balanced.

[0056] The plugin module of Fig. 4b may allow intrinsically safe devices / instrumentation to be connected to the intrinsically safe bus 4a, especially in a case where the intrinsically safe side 18b of the Ethernet switch lacks any power limitation circuitry 19b. Specifically, the plugin module may comprise power limitation circuitry 26b that is placed between the intrinsically safe bus 4a and the I / O port connectors 15b. The power limitation circuitry 26b may clamp the voltage and limit the current delivered to the I / O port connectors 15b, thus making the I / O port connectors 15b suitable for connecting to devices in hazardous areas.

[0057] The plugin module of Fig. 4c may allow intrinsically safe devices / instrumentation to be connected to the intrinsically safe bus 4a, especially in a case where the intrinsically safe side 18b of the Ethernet switch lacks any current limitation circuitry in the power limitation circuitry 19b, and only provides voltage clamping. Specifically, the plugin module may comprise current limitation circuitry 26c that is placed between the intrinsically safe bus 4a and the I / O port connectors 15c. The current limitation circuitry 26c may limit the current delivered to the I / O port connectors 15c, thus making the I / O port connectors 15c suitable for connecting to devices in hazardous areas.

[0058] The plugin module of Fig. 4d may allow non-intrinsically safe devices / instrumentation to be connected to the non-intrinsically safe bus 4b, and so does not require any isolator or power limitation circuitry between the non- intrinsically safe bus 4b and the I / O port connectors 15d. Thus, the I / O port connectors 15d are suitable for connecting to devices that are not subject to intrinsic safety requirements or that have higher power requirements. The plugin module of Fig. 4e may allow a combination of non-intrinsically safe and intrinsically safe devices / instrumentation to be connected to the intrinsically safe bus 4a. The plugin module may provide intrinsically safe I / / O port connectors 15e and non-intrinsically safe I / O port connectors 15f . The plugin module may comprise power limitation circuitry 26d that is placed between the intrinsically safe bus 4a and the I / O port connectors 15e, especially in a case where the intrinsically safe side 18b of the Ethernet switch lacks any power limitation circuitry 19b. The power limitation circuitry 26d may clamp the voltage and limit the current delivered to the I / O port connectors 15e, thus making the I / O port connectors 15e suitable for connecting to devices in hazardous areas. The plugin module may comprise an isolator 25b to provide galvanic isolation of power and data between the non- intrinsically safe I / O port connectors 15f and the intrinsically safe bus 4a. Thus, non- intrinsically safe devices / instruments can still be connected to the bus 4a if desired, via the I / O port connectors 15f , in combination with intrinsically safe devices / instruments via the I / O port connectors 15e.

[0059] This approach reduces the number of components required to fulfil the same typical functionality as a Remote Process I / O system and an Ethernet-APL Switch, comprising one or more Ethernet-APL Trunks and one or more Ethernet-APL 2- WISE / FISCO compatible Spurs. It is able to transmit / receive the Process I / O variables at a higher speed, by using a faster (e.g. SPI, I2C or Parallel or Ethernet) internal bus to transmit / receive the Process I / O variable data, from configurable, scalable, I / O type compliant pluggable Process I / O modules, to / from the Switch. The switch can efficiently map the Process I / O variable’s data into each Ethernet-APL telegram, along with the data to / from any connected Ethernet-APL Device, such that the size of the solution is comparably smaller and more compact, as well as comparably less expensive to produce. The Ethernet-APL trunk ports can transmit / receive a higher comparable bit-rate density for the process data, for the given system bit-rate of 10 Mbps or 100 Mbps.

[0060] In addition, the solution may be suitable for installation in Zone 1 Gas Group IIB or IIC areas, with input / output Intrinsically Safe connections to instruments or devices that are suitable for installing in Zone 0 Gas Group IIB or IIC areas, with the option of connecting to Non-lntrinsically Safe instruments or devices, suitable for installation in Zone 1 Gas Group IIB or IIC areas.

[0061] Many other variations of the described embodiments falling within the scope of the invention will be apparent to those skilled in the art.

Claims

CLAIMS1 . An I / O switch device comprising an Ethernet switch, a plurality of plugin module sockets having conductive terminals, and one or more internal busses for conveying both power and data from the Ethernet switch to the conductive terminals, wherein the Ethernet switch comprises at least one powered single-pair Ethernet trunk port, at least one powered single-pair Ethernet spur port, and an isolator between the at least one trunk port and the at least one spur port, wherein the isolator provides galvanic isolation of power and data between a non-intrinsically safe side of the Ethernet switch having the at least one powered single-pair Ethernet trunk port and an intrinsically safe side of the Ethernet switch having the at least one powered single pair Ethernet spur port; wherein the Ethernet Switch further comprises a power supply that is configured to power the Ethernet switch and the one or more internal busses from the at least one powered single-pair Ethernet trunk port.

2. The I / O switch device of claim 1 , wherein the intrinsically safe side of the Ethernet switch comprises power limitation circuitry for the at least one spur port, wherein the power limitation circuitry is connected between the isolator and the at least one spur port, and the power limitation circuitry comprises a voltage clamp, a current limiter, or a voltage clamp and a current limiter.

3. The I / O switch device of claim 1 or 2, wherein the internal busses comprise a non-intrinsically safe power and data bus connected from the non-intrinsically safe side of the Ethernet switch to a non-intrinsically safe one of the plugin module sockets.

4. The I / O switch device of claim 1 , 2 or 3, wherein the internal busses comprise an intrinsically safe power and data bus connected from the intrinsically safe side of the Ethernet switch to an intrinsically safe one of the plugin module sockets.

5. The I / O switch device of claim 4, wherein the intrinsically safe side of the Ethernet switch comprises power limitation circuitry for the intrinsically safe power and data bus, wherein the power limitation circuitry is connected between the isolator and the intrinsically safe power and data bus, and the power limitation circuitry comprises a voltage clamp, a current limiter, or a voltage clamp and a current limiter.

6. The I / O switch device of any preceding claim, wherein the internal busses are high-speed data buses of at least 10 Mbps.

7. The I / O switch device of any preceding claim, wherein the non-intrinsically safe and intrinsically safe sides of the Ethernet switch and the isolator are all formed on a single circuit board of the I / O switch device.

8. The I / O switch device of any preceding claim, wherein the Ethernet switch comprises an Ethernet controller / manager that is powered solely by the power supply.

9. The I / O switch device of any preceding claim, wherein the isolator provides capacitive, magnetic and / or optical isolation, for example in accordance with IEC60079 Part 11 :2023.

10. An I / O switch system comprising the I / O switch device of any preceding claim and a plugin module that has been physically plugged into one of the plugin module sockets to connect to the conductive terminals, the plugin module comprising one or more I / O port connectors for connecting I / O devices via respective cables.11 . The I / O switch system of claim 10, wherein the plugin module comprises a controller for receiving data from at least one of the I / O port connectors in accordance with a first communication protocol and sending data to the Ethernet switch via the conductive terminals in accordance with a second communication protocol that is different to the first communication protocol.

12. The I / O switch system of claim 11 , wherein the controller of the plugin module comprises a processor that is configured to process data received from at least one of the I / O port connectors before sending the data to the Ethernet switch.

13. The I / O switch system of claim 12, wherein the processor is remotely programmable via the Ethernet switch to define how the data is to be processed.

14. The I / O switch system of claim 11 , 12 or 13, wherein the controller of the plugin module is powered solely by power that is drawn from the internal bus connected to the conductive terminals.

15. The I / O switch system of any one of claims 10 to 14, wherein the plugin module comprises an isolator providing galvanic isolation between the conductive terminals and at least a first one of the I / O port connectors.

16. The I / O switch system of any one of claims 10 to 15, wherein the plugin module comprises power limitation circuitry connected between the conductive terminals and one or more of the I / O port connectors, wherein the power limitation circuitry comprises a voltage clamp, a current limiter, or a voltage clamp and a current limiter.

17. The I / O switch system of claim 16 when dependent on claim 15, wherein the power limitation circuitry of the plugin module is connected between the isolator of the plugin module and the first one of the I / O port connectors.

18. The I / O switch system of claim 14 or any claim dependent thereon, wherein at least a second one of the I / O port connectors does not have any isolator between the I / O port connector and the conductive terminals.

Images