Field devices for process equipment and systems including field devices

Abstract

In a field device (1a, 1b, 1c) used in process equipment such as chemical equipment (e.g., refineries), power plants (e.g., nuclear power plants), food processing equipment, etc., it includes a power distribution data exchange device (3) having an electrical primary connector (5) configured for power consumption at a first power level above 10W and at least two electrical secondary connectors (7, 8) for combined data communication and power transmission at each power level below 10W, and a housing (11a, 11b, 11c) for dustproof and waterproof installation of electrical components, the housing being shaped as follows: A first housing cavity (15) is formed, wherein the first housing cavity (15) is provided for pressure-resistant enclosure of electrical components for environments with explosive or flammable atmospheres and for housing a primary connector (5), wherein at least two secondary connectors (7,8) are arranged outside the pressure-resistant enclosure of electrical components for environments with explosive or flammable atmospheres, particularly outside the first housing cavity (15), wherein at least one, particularly a non-potentially isolated protective bridge (21) extends from the first housing cavity to connect the primary connector (5) to at least two secondary connectors (7,8).

Description

Technical Field

[0001] This invention relates to field devices for process equipment such as chemical equipment (e.g., refineries), power plants (e.g., nuclear power plants), food processing equipment, etc. Background Technology

[0002] Various data transmission technologies are employed in process equipment. Many field devices use combined two-wire connection mechanisms for combined signal and power transmission. In these mechanisms, a 4-20 mA signal is transmitted from the central control unit, such as the central control console of the process equipment, to the field device. In the case of a field device that functions as a control valve, for example, a 4-mA control signal can cause the control valve to move to the closed position, while a 20 mA signal can cause it to move to the fully open position. Signals within the 4-20 mA range can cause the control valve to be in a predetermined intermediate position between the closed and fully open positions, which may be proportional to a current signal, for example. Passive field devices in the form of sensors can transmit analog 4-20 mA signals to the central control unit to inform information about the conditions within the process equipment, such as parts or components of the process equipment or the process fluid. For example, a current signal may be transmitted to the central control unit proportional to a certain pressure range of a pressure sensor. The transmission of information or data using 4-20 mA signals is limited to very small amounts of data.

[0003] HART, basic fieldbus protocols, PROFIBUS, and a range of other digital communication technologies are also commonly used for data transmission within process equipment. Since 2007, HART has been part of the fieldbus standard IEC 61158. For data transmission according to the HART protocol, a high-frequency vibration, such as ±0.5 ohms, is superimposed on an analog signal, such as a 4.20-mA signal. Here, a digital 1 can be represented at a frequency of 1.2 kHz, and a digital 0 can be represented at a frequency of 2.2 kHz. HART allows process and fault diagnosis information, as well as control signals, to be transmitted between field devices and higher-level control units, such as a central control console.

[0004] In many process equipment systems, data is transmitted from a central control unit to field devices using so-called "active Ethernet" technology. Active Ethernet (PoE) refers to the technology that supplies current to networked devices via an 8-core Ethernet cable. Data transmission via PoE is performed according to the IEEE standard 8o2.3af (July 2003). Using an active Ethernet system should save on power cables to supply current to networked devices in hard-to-access or confined locations. According to IEEE standard 8o2.3af, the participating devices can be divided into power supply equipment (PSE) and users (PD). The operating voltage for users is specified as 48V. The maximum power consumption of the device is 350mA, with a permissible maximum of 400mA, resulting in a maximum power consumption of 14.5 watts per device. For power transmission, free cores and / or signal-conducting cores of the Ethernet cable can be used. PoE allows for the rapid transmission of large amounts of data. The power density of PoE technology does not allow for its application in areas with explosion hazards. The use of PoE technology comes at a significantly higher investment cost than similar 4.20-mA communications. Retrofitting existing process equipment with PoE technology also requires a huge investment, which is uneconomical in many cases. Field devices powered via Ethernet (active Ethernet) and the corresponding commissioning methods are described in DE102006036770A1.

[0005] The data transmission logic associated with this approach, utilizing both Ethernet and widely adopted process equipment communication technologies, is implemented, particularly according to the so-called Advanced Physical Layer (APL) technology based on the standard IEEE P8o2.3cg (2016). Unlike PoE, APL should be particularly suitable for integrating networkable instruments into areas under explosion threat (zones 0 and 1 / branch 1). Zone 0 describes an area where an explosive gas-air mixture is present for a prolonged or extended period. Zone 1 describes an area where flammable or conductive dust particles are present, as well as an area where an explosive gas-air mixture under normal operating conditions may be present temporarily. APL should also allow for the design of field devices to be inherently safe. Data transmission rates of 10 Mb / s to 100 Mb / s or higher should be achieved using stranded twin-core (stretched protective cable according to 10BASE-T1L). Process equipment equipped with APL can be equipped with so-called Trunk data and power transmission lines, particularly long, up to 1000m, from the central control unit to the APL field switch. The so-called Trunk line should be designed to transmit power up to 54W. Multiple field devices can be connected to so-called APL field switches via so-called track data and power transmission lines, typically up to 200 meters long. Track conductors are designed to provide power, usually up to 500mW. As data and power transmission lines, IEC 61158A type fieldbus cables are typically used, featuring stranded twin cores and an electrically shielded shell (also called a cover). According to the APL standard IEEE P8o2.3cg (2016), electrically shielded cables must be used for the connection between the APL field switch and each individual field device. Up to five field devices can be connected on a track conductor. Multiple, for example, up to ten APL field switches can be coupled to a single trunk line. APL technology is compatible with operating field devices in areas with explosion hazards. For this purpose, low power densities can be specified to prevent electrical and / or thermal energy present at the field devices from exceeding the ignition threshold, even under abnormal operating conditions. APL field switches and field devices are designed to be ignition-resistant (explosion-safe) according to protection class "Ex d".

[0006] APL technology allows for the transmission of large amounts of data and is compatible with existing two-wire communication systems. However, many users also complain about the high investment costs associated with equipping or retrofitting entire systems with APL technology. Summary of the Invention

[0007] The objective of this invention is to overcome the shortcomings of the prior art and, in particular, to provide a field device and / or a system that allows for safe and low-cost use with APL technology.

[0008] Therefore, a field device is specified for use in process equipment such as chemical equipment (e.g., refinery), power plants (e.g., nuclear power plants), food processing equipment, etc.

[0009] The field device has a power distribution data exchange device. This device has an electrical primary connector configured for power consumption at a first power level greater than 10 watts, particularly greater than 20 watts, and preferably greater than 50 watts. This primary connector can be referred to as a trunk terminal. Specifically, the primary connector is configured for power consumption not exceeding 100 watts, particularly not exceeding 75 watts, and preferably not exceeding 60 watts. For example, the primary connector can be configured for power consumption at a first power level of 54 watts. The primary connector is particularly suitable for combined data communication, especially digital data communication, and power consumption at the first power level.

[0010] The power distribution data exchange device also has at least two electrical secondary connectors for combined data communication, especially digital data communication, and power transmission at a second power level of less than 10 watts, particularly less than 1 watt, at each secondary connector. The at least two electrical secondary connectors can be configured for power transmission at a second power level of at least 1mW, at least 10mW, or at least 20mW. Preferably, one electrical secondary connector, particularly at least two electrical secondary connectors, and preferably all electrical secondary connectors of the power distribution data exchange device, can be configured for combined data communication, especially digital data communication, and power transmission at a second power level of no more than 0.5 watts at each secondary connector. The secondary connectors can be referred to as trace terminals.

[0011] The power distribution data exchange device may have exactly one electrical primary connector. The power distribution data exchange device may have at least two, at least five, at least ten, and / or no more than 150, no more than 100, or no more than 50 electrical secondary connectors.

[0012] The field device has a housing for dustproof and / or waterproof installation of electrical components. The housing can be designed, for example, according to a protection type of IP65 or higher. In particular, at least two electrical secondary connectors are arranged within the housing. In particular, electrical primary connectors are arranged within the housing. In particular, power distribution data exchange devices are arranged within the housing. The housing for dustproof and / or waterproof installation of electrical components can be defined, for example, according to the protection type of the so-called International Protection Code (IP code). The protection type describes the degree of protection of the housing against contact, foreign objects, water, etc. The IP code can be determined, for example, according to the respective 2014 effective versions of IEC 529, EN 60529, and DIN VDE 0470-1. The first digit of the IP code indicates protection against foreign objects and touch, with higher values ​​indicating superior protection. The first digit can have the following meanings: 3, protection against solid foreign objects larger than 2.5 mm and tool contact; 4, protection against solid foreign objects larger than 1 mm and wire contact; 5, protection against dust and touch; 6, protection against dust and touch. The second digit of the IP code relates to water resistance. The second number can have the following meanings: 3, splash-proof; 4, jet-proof; 5, water jet-proof; 6, severe water jet-proof; 7, temporary immersion-proof; 8, long-term immersion-proof. The enclosure can, for example, correspond to at least IP65, at least IP66, at least IP67, or at least IP68 protection levels.

[0013] The housing forms a first housing cavity. The housing may form a second or another housing cavity. The first housing cavity is configured to withstand pressure and enclose electrical components in environments with explosive or flammable atmospheres and to house primary connectors. Preferably, the first housing cavity completely houses the primary connector. In particular, the first housing cavity is configured solely to withstand pressure and enclose electrical components in environments with explosive or flammable atmospheres. An environment with explosive or flammable atmospheres may, for example, correspond to atmospheres in zone 0 or zone 1. According to one embodiment of the field device, the first housing cavity is defined by an outer wall of the housing in at least one section. The first housing cavity may be partially defined by two or more, three or more, particularly four or five outer walls of the housing. Field devices whose first housing cavity is defined by an outer wall of the housing in at least one section may have channels through which wires for connecting to an electrical primary connector within that section pass through the outer wall of the housing. For example, tubular trunk wires may extend through the outer wall to connect to the primary connector. Wires guided through the outer wall into the first housing cavity may, in particular, be configured as IEC 61158A type fieldbus cables. Wires passing through the outer wall of the housing, which may be the same or different defining housing compartments, particularly for combined data communication and power transmission, can be guided to the electrical third-level connector within the first housing compartment.

[0014] Electrical components are generally those components that are, or at least can be, powered for power and / or data processing during normal operation. Examples of electrical components include electronic computing devices such as microcontrollers or microprocessors; electronic pressure transducers, analog-to-digital converters, and digital-to-analog converters; electronic signal processing devices, data transmission devices, and / or load control devices.

[0015] Within the section of the outer wall of the housing that defines the first housing cavity, perforations for wires used to connect to the primary connector within the first housing cavity may be provided.

[0016] The at least two secondary connectors are specifically arranged entirely outside the pressure-resistant enclosure for electrical components in environments with explosive or flammable atmospheres. Specifically, the at least two secondary connectors are arranged outside the first housing cavity. Preferably, the electrical secondary connectors for combined data communication, especially digital data communication and power transmission, are arranged outside the pressure-resistant enclosure for electrical components in environments with explosive or flammable atmospheres, especially outside the first housing cavity. It is conceivable that a set of electrical secondary connectors for combined data communication and power transmission are arranged outside the pressure-resistant enclosure for electrical components in environments with explosive or flammable atmospheres, and a set of electrical tertiary connectors for combined data communication and power transmission are arranged inside the pressure-resistant enclosure for electrical components in environments with explosive or flammable atmospheres, especially within the first housing cavity. The first set of electrical secondary connectors are all specifically configured for power transmission at a second power level of no more than 1 watt, especially no more than 0.5 watts per secondary connector. Electrical third-level connectors or multiple electrical secondary connectors, especially all electrical secondary connectors of the second group, can be configured for power transmission at a third or second power level of less than 10 watts, especially not more than 5 watts and more than 0.5 watts, especially at least 1 watt.

[0017] According to the invention, at least one protective bridge, particularly one without potential separation, extends from a first housing compartment to connect a primary connector to at least two secondary connectors. It is likely preferred that the connection between the primary connector and the at least two secondary connectors be achieved solely by means of the protective bridge. For example, the protective bridge can be transferred from the first housing compartment containing the primary connector to another housing compartment containing at least two secondary connectors to connect the primary connector to the secondary connectors. The protective bridge passes through a pressure-resistant enclosure for environments with explosive or flammable atmospheres, defining the first housing compartment to allow electrical connections, particularly combined data communication and power transmission, from the primary connector to the at least two secondary connectors. Clearly, data communication and power transmission from the primary connector to the at least two secondary connectors can be performed indirectly by means of data exchange devices and / or load control devices. The protective bridge extending outward from the first housing compartment, particularly into the second housing compartment, is designed to intercept internal fire or explosion within the first housing compartment and to safely suppress breakdown or arcing into the external space and / or another housing compartment, particularly the second housing compartment.

[0018] According to one embodiment of the field device, the housing forms at least one additional housing compartment in which at least one secondary connector is arranged. This additional housing compartment is not designed to provide a pressure-resistant enclosure for electrical components in environments with explosive or flammable atmospheres. In particular, the additional housing compartment is arranged within the housing for dustproof and / or waterproof installation of electrical components. Preferably, the housing for dustproof and / or waterproof installation of electrical components has at least one additional housing compartment. This additional housing compartment may have the same or different protection type as the first housing compartment, such as IP65.

[0019] According to one embodiment of the field device that can be combined with prior embodiments, the protection bridge includes current isolators such as optocouplers and / or inductive couplers. Alternatively or additionally, the protection bridge may include an electrical power barrier. The electrical power barrier may be arranged in the first housing cavity and thus limit the power density of the wires extending from the first housing cavity via the electrical protection bridge, i.e., ensuring safety protection against ignition by explosive or flammable atmospheres outside the first housing cavity. The protection bridge may be designed to prevent spark discharge from electrical components inside the first housing cavity to electrical components outside the first housing cavity. The protection bridge may have at least one overvoltage and / or transient protection device. The protection bridge of the field device may, for example, have one optocoupler and / or inductive coupler for each electrical secondary connector.

[0020] In particular, the protection bridge of the field device may have a data coupler, such as an optocoupler and / or an inductive coupler, for each secondary connector for data communication from the primary connector to the respective secondary connector. Alternatively or additionally, the protection bridge may have a safe power coupler, particularly an inductive coupler, for each secondary connector for power transfer from the primary connector to the respective secondary connector. The data coupler and / or power coupler may have overvoltage and / or transient protection features. In particular, the protection bridge enables potential-free electrical connections between at least two electrical secondary connectors and electrical primary connectors, or between at least two electrical secondary connectors and a possible data exchange device and / or load control device. The protection bridge may have at least one data coupler and / or at least one power coupler for each secondary connector.

[0021] The protection bridge is configured to provide a power level of no more than 10 watts, particularly no more than 5 watts, preferably no more than 1 watt, and especially preferably no more than 0.5 watts, to each electrical secondary connector used for data communication and power transmission. The power coupler of the protection bridge can be configured to provide a power level of at least 10mW, particularly at least 100mW, and preferably at least 250mW, to the electrical secondary connector connected to the power coupler. The data coupler can be configured to provide a power level of no more than 250mW, particularly no more than 100mW, preferably no more than 50mW, and especially preferably no more than 1mW, to the secondary connector. Both the data coupler and the power coupler can be connected to the same electrical secondary connector of the field device.

[0022] According to one embodiment of the field device, which can be combined with prior embodiments, the power distribution data exchange device includes a load control device and a data transmission device, particularly a packet data exchange device, for transmitting digital data. Specifically, the load control device and / or data transmission device are housed in a first housing cavity. The load control device and / or data transmission device can be installed within the housing cavity to pressure-resistant enclosure electrical components for environments with explosive or flammable atmospheres. Specifically, the load control device is connected on one side to an electrical primary connector and on the other side to at least two electrical secondary connectors. The load control device can be configured to provide power from power consumption at a first power level for transmission at a second power level. The data transmission device, particularly a packet data transmission device, can be designed to ensure data communication, particularly digital data communication, from the primary connector to at least one of the at least two secondary connectors. On one hand, the data transmission device can be connected to the primary connector. The data transmission device is connected to the at least two secondary connectors in a manner suitable for signal transmission. The data transmission device can be configured to obtain the electrical state applied to at least one primary connector and / or secondary connector and / or provide a predetermined electrical state to at least one electrical primary connector and / or secondary connector. The data transmission device may be designed to convert electrical states obtained from primary and / or secondary connectors into digital data sets. The data transmission device may alternatively or additionally be configured to provide electrical signals to one or more primary and / or secondary connectors according to the digital data sets, which can be decoded into digital data values. The data transmission device may include at least one analog-to-digital converter and / or at least one digital-to-analog converter.

[0023] Preferably, the data exchange device, particularly by means of a data transmission device, establishes bidirectional data communication at the primary connector and / or at at least two secondary connectors. The data transmission device can filter and / or separate the electrical data signals from the primary connector to one of the at least two secondary connectors. For example, the data transmission device can be designed to distribute data, especially digital data, received via the primary connector to one of the at least two secondary connectors according to one or more predetermined standards. Field devices with load control and data transmission devices can be designed to separate the power supply at the first or second power level from the electrical data signals.

[0024] According to another embodiment that can be combined with prior embodiments, at least one electronic or electromechanical adjustment loop device for acquiring and / or influencing process parameters of the process equipment is disposed within the housing, particularly within a first housing cavity. In particular, the other and / or additional adjustment loop device is powered by power supplied via a primary connector. The adjustment loop device can be configured to directly or indirectly acquire and / or influence process parameters. The adjustment loop device can be, for example, a sensor such as a position sensor, pressure sensor, flow sensor or flow rate sensor, temperature sensor, etc., which generates and transmits sensor signals based on process states to, for example, control devices and / or adjustment devices. The sensor generates actual signals for the control device and / or adjustment device, particularly control electronics and / or adjustment electronics. The adjustment loop device may include control electronics and / or adjustment electronics. The control electronics and / or adjustment electronics can be configured to process theoretical signals obtained from a higher-level control unit, such as a central unit, such as the control console of the process equipment, to provide control signals and / or adjustment signals to the actuators prepared for operating the process equipment.

[0025] Control and / or adjustment electronics can be configured to generate control and / or adjustment signals based on theoretical and actual signals. These devices can be implemented, for example, as digital position adjusters, having a computing unit, a storage unit, and at least one signal input and at least one signal output. The computing unit of the control and / or adjustment electronics can be designed to determine the control and / or adjustment signals based on theoretical signals and, possibly, actual signals, using a processor or similar device, according to control and / or adjustment routines that can be stored in memory. Adjustment routines can be implemented, for example, using PID adjustment routines, two-point adjustment routines, three-point adjustment routines, or combinations thereof. The control and / or adjustment electronics can be configured to utilize these adjustment routines. The adjustment loop device can include a transducer, such as an electro-pneumatic transducer. Electro-pneumatic transducers can be configured to provide corresponding pneumatic control and / or adjustment signals based on electrical control and / or adjustment signals, particularly for pneumatic actuators. Field devices designed in this way are particularly suitable for applications with limited structural space. Because the primary connector and at least one adjustment circuit device, and perhaps a data transmission device and / or load control device are installed in a first housing cavity, in particular the same one, to provide a pressure-resistant enclosure for the aforementioned electrical components in environments with explosive or flammable atmospheres, the effort required to protect multiple electrical components can be significantly reduced, thereby saving costs.

[0026] According to a particular embodiment of a field device for process equipment such as chemical equipment (e.g., refineries), power plants (e.g., nuclear power plants), food processing equipment, etc., having a housing for dustproof and / or waterproof installation of electrical components, a power distribution data exchange device having one primary connector and at least two electrical secondary connectors, and at least one electronic or electromechanical adjustment circuit device for acquiring and / or influencing process parameters of the process equipment are installed within the housing. In particular, the power distribution data exchange device installed within the housing can be an APL field switch. In this particular design of the field device, an electrical primary connector configured for power consumption at a first power level greater than 10 watts can be provided. In the specially designed field device, at least two electrical tertiary connectors can be provided within the housing for combined data communication and power transmission at a second power level less than 10 watts at each secondary connector. In this particular design of the field device, the additional electronic or electromechanical adjustment circuit device can be powered solely by the power supplied via the primary connector. This particular embodiment of the field device can be arbitrarily combined with the preceding embodiments and the embodiments described later. The special design of the field device can be achieved in particular by the following field devices, which include the same housing as the power distribution data exchange device in the form of an APL field switch for dust and / or water protection, especially in accordance with IEEE P8o2.3cg, and adjustment loop devices for acquiring and / or influencing process parameters of the process equipment.

[0027] According to an improved embodiment, the regulating circuit device is supplied with power by means of a load control device, particularly by a third-level connector installed in the first housing cavity for combined data communication, especially digital data communication, and power transmission at a second power level of less than 1 watt, especially not greater than 0.5 watts.

[0028] According to an improved embodiment, the adjustment loop device is a regulator for adjusting a controllator. The regulator has at least one signal input for receiving actual signals about the regulator, such as an actual position signal, and an output for operating the regulator. The regulator can be an instrument designed for controlled intervention in a technological process. The regulator is preferably housed outside a housing. The regulator may have its own regulator housing designed for dustproof and / or waterproof mounting of the electrical regulator components. The regulator housing may be configured to provide a pressure-resistant enclosure for the electrical regulator components in environments with explosive or flammable atmospheres.

[0029] Regulators can be designed to be inherently safe. Inherently safe regulators or other inherently safe electrical components can be designed to be inherently safe, i.e., without unsafe conditions even under abnormal fault conditions. Fault conditions are described, for example, as situations where there is a risk of ignition or other danger, such as the possibility of an electric spark when a current circuit is connected in an area with an explosion hazard. Inherently safe regulators or other electronic components can be implemented according to an ignition-resistant inherent safety type (“Ex i”, for example, according to IEC-EN 60079-11, parts 11, 14 and / or 25). Inherently safe regulators or other inherently safe electronic components are designed such that the applied current intensity and voltage are limited to prevent ignition of an explosive fuel / air mixture caused by electric sparks and heating, especially during normal operation, for example, when assembling and / or disconnecting wiring, and / or under fault conditions such as in the event of a broken wire or short circuit. Voltage limiting can be achieved, for example, through the resistance, Zener barrier and / or electronic current limiting mechanism of the inherently safe electronic components or inherently safe regulators.

[0030] According to another improvement to the field device, the adjustment circuit device is arranged within the first housing cavity and has a pneumatic output terminal for operating a pneumatic actuator, particularly a pneumatic pressure regulating drive device, located within the first housing cavity. The pneumatic output terminal of the adjustment circuit device and a possible pneumatic supply inlet for the same adjustment circuit device can be achieved through a protected pneumatic air passage. The protected pneumatic air passage ensures that the electrical components of the field device are pressure-resistant and enclosed within the first housing cavity for environments with explosive or flammable atmospheres. The protected pneumatic air passage can be implemented in a section of the first housing cavity through the outer wall of the housing. The pneumatic pressure regulating drive device is, for example, provided for operating a regulating valve.

[0031] According to another improvement to the field device, the adjustment loop device includes a position sensor disposed in the first housing cavity for determining the position of the regulator. In particular, the position sensor is designed to determine the position of the regulator's adjusting rod or adjusting shaft. The adjusting rod or adjusting shaft is preferably disposed only outside the first housing cavity, and particularly entirely outside the housing.

[0032] In particular, the position sensor is coupled to the regulator in a non-contact manner. This non-contact coupling can include magnetic coupling and / or electromagnetic coupling. The non-contact coupling preferably includes at least one magnet or electromagnet, preferably fixedly positioned to an adjusting rod or adjusting shaft of the regulator, and a corresponding magnetic sensor, such as an AMR, mounted within a first housing cavity. Obviously, those skilled in the art can use other suitable non-contact couplings, such as optical coupling, instead of non-contact magnetic or electromagnetic coupling.

[0033] Alternatively or additionally, the position sensor is mechanically connected to the regulator. The outer wall of the housing may include a sleeve for the mechanical connection. For example, the mechanical connection of the position sensor may include a sensor shaft, and the outer wall of the housing has a swivel joint for the sensor shaft. The sensor shaft can extend from the first housing cavity into its unprotected environment to reach the regulator, particularly an adjustment rod or adjustment shaft. The sensor shaft is mechanically connected to the regulator, particularly an adjustment rod or adjustment shaft. The swivel joint ensures a pressure-resistant enclosure within the first housing cavity for the electrical components of the field device relative to environments with explosive or flammable atmospheres.

[0034] This document relates to a system comprising a field device as described above and a regulator, particularly a control valve, having at least one transducer, especially an electro-pneumatic transducer, and / or a physical signal transmitter such as a position sensor, disposed outside the housing of the field device. The regulator's electrical signal inputs and / or outputs are connected to secondary connectors of the field device. The transducer is preferably designed to be inherently safe. The transducer includes electrical signal inputs and / or outputs, which are provided via external conductors for data and / or power transmission. At least one, especially exactly one, external conductor for data and / or power transmission is provided between one, especially exactly one, secondary connector of the regulator and the transducer. The external conductor for data and / or power transmission connects the transducer disposed outside the housing to an electrical secondary connector, particularly disposed within a housing, preferably another housing cavity, for unidirectional or bidirectional data transmission and / or unidirectional and bidirectional power transmission. The transducer preferably includes a transducer housing for dustproof and / or waterproof mounting of the transducer's electrical components. In particular, the transducer housing is configured to be a pressure-resistant enclosure for electrical transducer components in environments with explosive or flammable atmospheres. The housing used for pressure-resistant enclosures can be, for example, an explosion-proof housing.

[0035] The transducer can be configured to receive electrical signals, such as analog signals, from field devices and convert them into data signals, particularly control and / or adjustment signals for regulators, or into pressure control and / or adjustment signals, for example, for pressure regulators. The transducer can also be configured to generate data signals for field devices based on process conditions. For example, the transducer can be a position sensor, pressure sensor, flow sensor, temperature sensor, etc., which measures process conditions such as position, pressure, temperature, flow rate, flow volume, vibration, etc., and generates corresponding data signals to transmit to the field devices. The data signals generated by the transducer based on process conditions are particularly actual signals. Preferably, the outer conductor is designed as a simple two-core cable without a tubular electrical seal for use in environments with explosive or flammable atmospheres for data and / or power transmission. Attached Figure Description

[0036] Other features, performance, and advantages of the present invention will become clear from the following description of preferred embodiments, wherein:

[0037] Figure 1 A schematic diagram showing a first embodiment of the field device;

[0038] Figure 2 A schematic diagram of a system with another embodiment having field devices is shown; and

[0039] Figure 3 Another implementation of the system with field devices is shown. Detailed Implementation

[0040] For ease of readability, the same or similar reference numerals are used for the same or similar parts in the following description of preferred embodiments.

[0041] The field device 1a, as a main component, includes a power distribution data exchange device 3 having one primary electrical connector 5 and at least two secondary electrical connectors 7, 8, and a housing 11a for dustproof and / or waterproof installation of electrical components. The housing forms a first housing cavity 15 to accommodate the primary connector 5. The at least two secondary connectors 7, 8 are mounted in another housing cavity 17 of the housing 11a. Figure 1 In the preferred embodiment of the field device 1a shown, the electrical components 5, 7, and 8 of the power distribution data exchange device 3 are all mounted in the housing 11a, thereby protecting them, in particular, from dust and / or water from the field device environment according to protection type IP-65 or higher.

[0042] The first housing cavity 15, which fully accommodates the primary connector 5, is provided for sealing electrical components within a pressure-resistant enclosure 200 for use in environments with explosive or flammable atmospheres, while the other housing cavity 17, which houses the secondary connectors 7 and 8, is not provided for this purpose.

[0043] The primary electrical connector 5 is configured for power consumption at a first power level greater than 10 watts. Specifically, the primary electrical connector 5 can be implemented for power consumption at a first power level of 45 watts and / or in a so-called Trunk terminal form corresponding to the APL standard IEEE P803.2cg. These secondary electrical connectors 7 or 8, or perhaps other (not shown in detail) are designed to combine data communication and power transmission at a second power level of less than 10 watts per secondary connector, particularly no more than 5 watts per secondary connector, and preferably no more than 0.5 watts per secondary connector.

[0044] The housing 11a has an outer wall 13 that separates the inner cavity of the housing 11a, which is divided into cavities 15 and 17, from the environment 200 of the field device 1a. The housing wall 13 may be designed, for example, to have a seal corresponding to an IP-65 protection type. Only the first housing cavity 15 is also designed to be pressure-resistant to environments with explosive or flammable atmospheres, so that an explosion, fire, or electrical spark within the first housing cavity 15 does not have a harmful effect on the environment 200 outside the first housing cavity 15. Even when the environment 200 outside the first housing cavity 15 is filled with flammable or explosive gases according to so-called zone 0 or zone 1, the enclosure of the first housing cavity 15 ensures that an ignition source or even an ignition element within the first housing cavity 15 does not affect the environment 200 outside the first housing cavity 15. Thus, electrical components such as non-inherently safe primary connectors 5 can be used within the first housing cavity 15, for example, because the power density they face exceeds permissible limits. The enclosure provided by the first housing compartment 15 ensures that internal fire, internal explosion, electrical breakdown, or arcing will be reliably prevented in the external space 200 or in another housing compartment 17.

[0045] Another housing cavity 17 is disposed in the environment 200 outside the first housing cavity 15. Flammable or explosive gases or gas mixtures may be present within the second housing cavity 15. Electrical components disposed in the second housing cavity 17, such as electrical secondary connectors 7, 8, are designed to transmit power for combined data communication, and are particularly designed to be securely used for power transmission at power levels below 10 watts, especially below 1 watt, and preferably no more than 0.5 watts per secondary connector.

[0046] The interior of housing 11a is divided into a first housing cavity 15 and another housing cavity 17 by the inner wall 16. The dustproof and waterproof protection type may be the same for all cavities 15, 17, etc., of housing 11a. Alternatively, it is conceivable that the first housing cavity 15 and the other housing cavity 17 may be designed according to different dustproof and waterproof protection types, wherein the first housing cavity 15 may correspond to a higher dustproof and / or waterproof seal than the other housing cavity 17.

[0047] Within the first housing cavity 15, the load control device 31 and the data transmission device 33 are connected to the electrical primary connector 5. According to... Figure 1 In the diagram, bidirectional data communication is represented by lines with open boxes. According to... Figure 1In the schematic diagram, the power supply line is shown as a line with an arrow pointing towards the user. The direction of power flow is indicated by the arrow. The data transmission device 33 is connected to the primary connector 5 via a bidirectional data transmission line 35 to transmit, in particular, digital data. The power control device 31 is supplied with power from the primary connector 5 via supply line 37. From the load control device 31, the electrical components of the data exchange device 3 are supplied with electrical energy via different supply lines 36, 38, and 39.

[0048] The protective bridge 21 extends from the first housing cavity 15 through the inner wall 16 of the housing to the electrical secondary connectors 7, 8. Unlike smooth electrical connection wires, the protective bridge 21 ensures, through the use of secure data and / or power couplers 41, 42, 43, 44, ignition and / or explosion protection around the electronic components located outside the first housing cavity 15, for example, according to inherent safety standards. The data couplers 43, 44 and the power couplers 41, 42 may include, for example, current isolation. The data couplers 43, 44 may be implemented as optocouplers or inductive couplers, for example. The power couplers 41, 42 may be implemented as inductive couplers, for example. It is conceivable that the data and / or power couplers 41, 42, 43 and / or 44 include an electrical power barrier.

[0049] Data couplers 43 and 44 connect their respective secondary connectors 7 and 8 to the data transmission device 33 for data communication. An internal data line 47 is disposed between the first data coupler 43 and the data transmission device 33 within a first housing cavity 15. The first data coupler 43 is connected to the external data line 75 via the first secondary connector 7 in a second housing cavity 17. The second data coupler 44 is connected to the data transmission device 33 via the internal data line 48 in the first housing cavity 15, and to the secondary secondary connector 8 via the external data transmission line 75 in the other housing cavity 17.

[0050] Internal supply lines 38 and 39 extend from the load control device 31 to either the first power coupler 41 or the second power coupler 42. External supply line 77, outside the first power coupler 41, connects to the first secondary connector 7. External supply line 77, outside the second power coupler 42, connects to the second secondary connector 8. Wires located outside the housing 11a for data and / or power transmission devices 117a and 118a connect to the secondary connectors 7 and 8. One or more components of the process equipment, such as position adjusters or position sensors, may be coupled to each external wire 117 or 118. (Regarding...) Figure 2 The second embodiment of the field device 1b will be described in detail below. External conductors 117a and 118a are guided from the housing 11 through their respective through holes 167 and 168, which (aside from waterproof and / or dustproof protection) are designed without special protection.

[0051] A through-hole 65 for a main conductor 60 for power and data transmission is provided in the portion 13 of the housing 11a surrounding the first housing cavity 15. The main conductor 60 for data and power transmission is coupled to the primary connector 5. The main conductor 60 is surrounded by a tubular enclosure 63, thereby establishing safety for use in environments with explosive or flammable atmospheres. Since the tubular enclosure 63 is inserted through the through-hole 65 in the outer wall 13 of the housing, there is no adverse impact on the safety enclosure of the first housing cavity 15. The main conductor 60 can be, for example, a so-called trunk cable. In particular, the main conductor 60 can be designed as a protected two-core wrapped shielded enclosure of a sheathed fieldbus cable according to IEC 61158A type.

[0052] exist Figure 2 and Figure 3 Other embodiments of field devices 1b and 1c are shown. Field devices 1b and 1c are related to... Figure 1 The main difference in the field device of a lies in the fact that, within the first housing cavity 15, an electrical component is attached to and installed a primary connector 5, a power divider and a data transmission device 33, and at least one electronic or electromechanical adjustment circuit device 51b, 51c. According to... Figure 2 and Figure 3 In the field devices 1b and 1c, the additional adjustment circuit devices 51b and 51c are safely protected against environments 200 with explosive or flammable atmospheres because they are installed within a pressure-resistant enclosure provided by the first housing cavity 15. Regarding the remaining design of the field devices 1b or 1c, and especially the power distribution data exchange device 3, the above points out... Figure 1 Description of the field device 1a shown.

[0053] Figure 2 The field device 1b is shown. In addition to the power distribution data exchange device 3, which may be equipped in this embodiment as a third-level connector 9, such as an APL field switch, an electronic adjustment circuit device 51b is also provided in its housing 11b. It is set as an adjuster, that is, a position adjuster for the regulator 110b.

[0054] The regulator is illustrated herein as a pneumatic control valve 100b. The pneumatic control valve 100b includes a pneumatic pressure regulating actuator 101b and a control valve 105b operated via a force-transmitting adjusting rod 103b through the pneumatic pressure regulating actuator 101b. According to an alternative design, the control valve may have an adjusting shaft (not specifically shown) for the rotary motion of the valve. The position adjuster 51b is connected to the power distribution data exchange device 3 via a third-stage connector 9. The third-stage connector 9 of the power distribution data exchange device 3 may be configured, for example, as a conventional trace terminal. The third-stage connector is located within the first housing cavity 15 of the field device 1b. The third-stage connector 9 provides for combined data communication, especially digital data communication, and power transmission at a second power level not exceeding 10 watts, especially not exceeding 1 watt, preferably not exceeding 0.5 watts. Obviously, the field device may have other numbers of multiple third-stage connectors 7, 8, and / or third-stage connectors 9. The third-level connector 9 includes a data transmission line 95 and a supply line 97 for transmitting power from the data exchange device 3 to the adjustment circuit device 51b. The adjustment circuit device 51b has a terminal interface 53b, which serves as a power input terminal as well as a signal input terminal and an output terminal.

[0055] The position adjuster 51b can receive actual signals, such as the actual position signal from the position sensor 120b of the pressure regulator 100b, at its signal input terminal 53b. At the signal output terminal 53b of the position adjuster 51b, the position adjuster can output control and / or regulation signals for the regulating valve 100b. At the signal input terminal 53b, the position adjuster 51b can also receive theoretical signals from other sources, such as a central control unit like the central control console of a process equipment, which can be provided to the field device 1b via the main line 60. The input terminal 53b of the position adjuster 51b is connected to a third-stage connector 9 for power supply to the position adjuster 51b.

[0056] An electronic pneumatic transducer 110b for generating pneumatic control signals based on electrical control signals from position adjuster 51b is disposed outside the housing 11 of field device 1b. The electronic pneumatic transducer 110b has its own transducer housing 123. The electronic pneumatic transducer is connected via a pneumatic line 116b to a pneumatic actuator 101b, such as a one-way pneumatic drive with spring return. The electronic pneumatic transducer 110b also includes supply and / or relief terminals 119b for connection to a compressed air source or compressed air trap.

[0057] The electronic pressure transducer 110b is inherently safe. The electronic pressure transducer 110b has an electrical signal input terminal 111, which is connected via an external conductor to the primary connector 7 of the field device 1b for data and / or power transmission 17b. Control signals from the position adjuster 51b are transmitted to the electronic pressure transducer 110b via the secondary connector 7 and the primary external conductor 117b. When the electronic pressure transducer 110b, for example, does not have the capability to generate its own communication signals, i.e., cannot send signals back to the field device 1b, the conductor for data transmission 117b can be designed to be unidirectional. Alternatively, the data transmission line 117b from the electronic pressure transducer 110b to the field device 1b can be designed to be bidirectional, thus enabling the electronic pressure transducer 110b to transmit signals such as actual signals regarding the supply pressure or fault diagnostic codes from the field device 1b. Signals from the electronic pneumatic converter 110b can be transferred from the data exchange device 3 via the primary connector 5 and / or the tertiary connector 9 to other electronic components such as the central control console or position adjuster 51b.

[0058] As other converters, Figure 2 The system shown includes a position sensor 120b that measures the absolute or relative position of the adjustment lever 103b to generate a position signal, which is then communicated to the position adjuster 51b. The position sensor 120b has a signal output terminal 121 for transmitting the position signal via a second external conductor 118b for data and / or power transmission. The conductor 118b connects the secondary connector 8 of the field device 1b to the signal output terminal 121 of the position sensor 120b. The position sensor 120b is enclosed within its own transducer housing 123.

[0059] The regulator housing or converter housing 123 may be provided with a dustproof and / or waterproof shielding enclosure for electrical components housed within the environment 200. The converter housing 123 may alternatively or additionally be provided with a pressure-resistant enclosure for electrical converter components housed within the environment 200 containing explosive or flammable atmospheres. The actual position signal generated by the position sensor 120b is transmitted from the data exchange device 3 via data line 95 between the third-level connector 9 and the signal input terminal 53b to the position adjuster 51b. The data exchange device 3 may be additionally or alternatively designed to transmit actual signals from sensors such as the actual position signal and the position sensor 120b via the primary connector 5 and the main wire 60 connected thereto to other components such as a central control console.

[0060] Figure 3Another embodiment of the field device 1c is shown, in which, in addition to the power distribution data exchange device 3, another adjustment loop device 51c is provided within the housing 11c. In the embodiment shown here, the adjustment loop device 51c is implemented in the form of an adjuster for adjusting the regulator 100c, i.e., in... Figure 3 For example, this is presented as a pneumatic position adjuster 51c for a pneumatic control valve 100c. The adjuster 51c has a specially designed signal input terminal 120c for receiving actual signals, i.e., actual position signals regarding the adjuster 100c. The signal input terminal 120c is connected to the adjuster 100c via an external conductor 122. The external conductor 122 may be surrounded by a tubular enclosure (not shown in detail here). The conductor 122 extends outside the first housing cavity 15 of the housing 11c to connect the signal input terminal 120c to the adjuster 100c. The extension of the external conductor 122 may be designed to pass protectively through the outer wall 13 of the housing 11c surrounding the safety separation cavity 15, thus ensuring that the pressure-resistant enclosure of electrical components for an environment 200 with an explosive or flammable atmosphere, achieved through the first housing cavity 15, remains uncompromised. The external conductor 122 may connect the signal input terminal 120c, for example, to a stop key on the valve stem 103c, which measures the open and / or closed position of the valve 103c.

[0061] The pneumatic electric position adjuster 51c also includes an electronic pneumatic transducer 110c, which is designed as part of the pneumatic electric position adjuster 51c and is installed within the first housing cavity 15. For connection to a compressed air source and / or a compressed air trap, the outer wall 13 of the housing 11c is provided with a protected air port 119c. Another secure air port through the outer wall 13 of the housing 11c is provided for a pneumatic supply line 116c to operate the pneumatic actuator 101c via the electronic pneumatic transducer 110c.

[0062] It is clear that, as an alternative to the above-described embodiments, other alternatives, such as hybrid methods, can also be implemented. For example, an electronic pneumatic position adjuster (not shown in detail) is arranged in the first housing cavity 15 and connected to the actual signal input terminal of the state sensor mounted on the adjuster via an external wire, wherein the electronic pneumatic converter of the position adjuster is arranged outside the field device housing.

[0063] Alternatively, the electronic pneumatic converter of the electronic pneumatic position adjuster can be installed in the first housing cavity 15, and the status sensor can be indirectly connected to the position adjuster (not shown in detail) via a secondary connector.

[0064] According to another conceivable alternative, a field device is provided along with a non-contact, such as inductive, position or attitude sensor disposed therein, arranged near the adjusting rod or adjusting shaft. In particular, a magnet or similar non-contact position signal transmitter can be positioned on the adjusting rod or adjusting shaft, and a non-contact position sensor (not shown in detail) for obtaining the actual position of the regulator is provided within the first housing cavity 15. It is conceivable that such a field device could include an electro-pneumatic transducer for operating a pneumatically driven regulating valve, which could be disposed either within or outside the first housing cavity.

[0065] According to another alternative embodiment (not shown in detail) that can be combined with the foregoing embodiments, a position sensor can be disposed within the first housing cavity, which is mechanically connected to the adjusting rod or adjusting shaft to determine the actual position of the regulator. Specifically, the adjusting movement of the adjusting rod or adjusting shaft can be converted into rotational movement of the sensor shaft, which reaches the first housing cavity 15 via a rotary joint for the sensor shaft. The rotational movement of the sensor shaft can then be recorded by a position sensor such as a magnetic field-sensitive position sensor.

[0066] Obviously, as an alternative to the electronic pneumatic converter for operating the pneumatic drive device described and illustrated herein, an electrical supply output terminal may be provided, or combined with an electrical control output terminal for operating the electrical actuator. The electrical regulating actuator may, for example, drive an adjusting rod, adjusting shaft, or pump.

[0067] The features disclosed in the above description and figures are meaningful not only individually but also in any combination for implementing the invention with different design schemes.

[0068] Attached Figure

[0069] 1a, 1b, 1c Field devices

[0070] 3 Power Distribution Data Exchange Device

[0071] 5. Primary Connector

[0072] 7,8 Secondary connectors

[0073] 9. Third-level connector

[0074] 11a, 11b, 11c Shell

[0075] 13 Outer wall of the shell

[0076] 15 First shell cavity

[0077] 16. Inner wall of the shell

[0078] 17 Another housing compartment

[0079] 21 Protect the bridge

[0080] 31 Load control device

[0081] 33 Data transmission device

[0082] 35 Data transmission lines

[0083] Supply lines 36, 37, 38, 39

[0084] 41,42 Data Couplers

[0085] 43,44 Power Couplers

[0086] 51b, 51c Adjustment circuit device

[0087] 53b, 53c signal input and / or output terminals

[0088] 60 Dominant Line

[0089] 63 Tubular Enclosure

[0090] 65 piercing

[0091] 75 Data transmission line

[0092] 77 Supply Line

[0093] 100b, 100c regulators

[0094] 101b, 101c Air pressure regulating drive device

[0095] 103b, 103c Adjustment rod

[0096] 105b, 105c regulating valves

[0097] 110b, 110c Electronic Pneumatic Transducer

[0098] 111, 112 Signal input and / or output terminals

[0099] 116c air pressure signal output terminal

[0100] 117a, 118a External data and / or power transmission lines

[0101] 117b, 118b External data and / or power transmission lines

[0102] 117c External data and / or power transmission lines

[0103] 119c Protected pressure port

[0104] 120b position sensor

[0105] 121 Signal Output Terminal

[0106] 122 wire

[0107] 123 Regulator or converter housing

[0108] Channels 167 and 168

[0109] 200 Environment

Claims

1. A field device (la, lb, lc) for a process plant, the field device (la, lb, lc) comprising: Power distribution data exchange device (3) in the form of an APL switch, having an electrical primary connector (5) configured for consuming power at a first power level above 10 W and at least two electrical secondary connectors (7, 8) for combined data communication and power transmission at power levels each below 10 W, characterized by a housing (11a, 11b, 11c) for dust- and / or water-tight mounting of electrical components, which housing forms a first housing compartment (15), wherein the first housing compartment (15) is provided for pressure-tight encapsulation of electrical components against an environment with an explosive or ignition atmosphere and accommodates the primary connector (5), and wherein the at least two secondary connectors (7, 8) are arranged outside a pressure-tight encapsulation of electrical components against an environment with an explosive or ignition atmosphere, outside the first housing compartment (15), wherein at least one protective bridge (21) extends from the first housing compartment to connect the primary connector (5) to the at least two secondary connectors (7, 8), wherein the protective bridge (21) has a power coupler for power transmission from the primary connector (5) to the respective secondary connector (7, 8) and / or is arranged such that the power level of each electrical secondary connector (7, 8) for data communication and power transmission does not exceed 10 W.

2. Field device (1 a, 1 b, 1 c) according to claim 1, characterised in that The housing (11a, 11b, 11c) forms at least one further housing compartment (17) in which at least one secondary connector (7, 8) is arranged, wherein the at least one further housing compartment (17) is not provided as a pressure-tight encapsulation of electrical components against an environment with an explosive or ignition atmosphere.

3. Field device (1 a, 1 b, 1 c) according to one of the preceding claims, characterized by The first housing compartment (15) is delimited in at least one section by an outer wall (13) of the housing (11a, 11b, 11c).

4. Field device (1 a, 1 b, 1 c) according to claim 1, characterised in that The protective bridge (21) comprises a galvanic isolator and / or an electrical power barrier.

5. Field device (1 a, 1 b, 1 c) according to claim 1, characterised in that The power distribution data exchange device (3) comprises a load control device (31) and a data transmission device (33).

6. Field device (1 b, 1 c) according to claim 1, characterised in that At least one electronic or mechatronic regulating loop device (51b, 51c) for obtaining and / or influencing a process parameter of the process engineering device is mounted in the housing (11b, 11c).

7. Field device (1 b, 1 c) according to claim 6, characterised in that The regulating loop device (51b, 51c) is supplied with electrical power by means of the load control device (31).

8. Field device (1 b, 1 c) according to claim 6 or 7, characterised in that The regulating loop device (51b, 51c) is a regulator for regulating a regulator (100b, 100c), wherein the regulator has at least one signal input (53b; 53c) for receiving an actual signal relating to the regulator (100b, 100c) and an output (53b, 53c) for operating the regulator (100b, 100c).

9. Field device (1 c) according to claim 8, characterised in that The regulating loop device (51c) has a pneumatic output (110c) for operating a pneumatic actuator (101c) arranged in the first housing compartment (15).

10. Field device (1 b, 1 c) according to claim 8, characterised in that The regulating loop device (51b, 51c) comprises a position sensor arranged in the first housing compartment (15) for ascertaining a position.

11. Field device (la, lb, lc) according to claim 1, characterized by The process plant is a chemical plant, a power plant, a food processing plant.

12. Field device (la, lb, lc) according to claim 11, characterized by The chemical plant is a refinery.

13. The field device (la, lb, lc) according to claim 11, characterized by The power plant is a nuclear power plant.

14. The field device (la, lb, lc) according to claim 1, characterized by At least one galvanically isolated protective bridge (21) projects from the first housing compartment to connect the primary connector (5) to the at least two secondary connectors (7, 8).

15. The field device (1 a, 1 b, 1 c) according to claim 4, characterized by The current isolator is an optocoupler (41, 42) and / or an inductive coupler (43, 44).

16. The field device (1 a, 1 b, 1 c) according to claim 5, characterized by The load control device (31) and / or the data transmission device (33) are accommodated in the first housing compartment (15).

17. Field device (1 b, 1 c) according to claim 6, characterized in that At least one electronic or mechatronic regulating loop device (51b, 51c) for obtaining and / or influencing a process parameter of the process plant is installed in the first housing compartment (15).

18. The field device (1 b, 1 c) according to claim 6, characterized by The regulating loop device (51b, 51c) is supplied with electrical power supplied via the primary connector (5).

19. The field device (1 b, 1 c) according to claim 7, characterized by The regulating loop device (51b, 51c) is supplied with electrical power by means of the load control device (31) via a third level connector (9) installed in the first housing compartment (15) which is set up for combined data communication and power transmission at a power level below 10 W.

20. The field device (1 b, 1 c) according to claim 8, characterized by The actual signal is an actual position signal.

21. The field device (1 c) according to claim 9, characterized by The regulating loop device (51c) has a pneumatic output (110c) for operating a pneumatic actuator (101c) arranged in the first housing compartment (15).

22. The field device (1 b, 1 c) according to claim 10, characterized by The regulating loop device (51b, 51c) comprises a position sensor arranged in the first housing compartment (15) for ascertaining a position of an actuating lever (103b, 103c) or an actuating shaft of the actuator (100b, 100c).

23. The field device (1 b, 1 c) according to claim 10, characterized by The position sensor is coupled to the actuator (100b, 100c) in a contactless and / or mechanical manner.

24. A system comprising a field device (1a, 1b, 1c) according to any one of the preceding claims 1 to 23 and an actuator (100b, 100c) having at least one transducer arranged outside a housing (11a, 11b, 11c) and / or an actual signal transmitter having an electrical signal input and / or output (111, 121) connected to a secondary connector (7, 8) of the field device (1a, 1b, 1c).

25. The system of claim 24, wherein, The transducer is an electronic pneumatic transducer (110b).

26. The system of claim 24, wherein, The actual signal transmitter is a position sensor (120b).

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