MXPA00003290A - Communication technique for field devices in industrial processes - Google Patents

Abstract

A process device (32) is adapted to couple to a process control loop (36) and communicate on the process control loop (36). Communication on the process control loop (36) is effected in accordance with an internet protocol. A process communication device (34) is also provided which couples to the process control loop (36), and an internet (42). The process communication device (34) provides process control information received from the process control loop (36), to the internet (42). Conversely, the process communication device (34) also provides information received from the internet (42) to the process control loop (36).

Description

COMMUNICATION TECHNIQUE FOR FIELD DEVICES IN INDUSTRIAL PROCESSES BACKGROUND OF THE INVENTION The invention relates to the fluid control prooeso industry. More specifically, the invention relates to field devices used in the process control industry and the manner in which those devices are communicated in the field. Field devices such as transmitters are used in the process control industry to remotely detect a process vari. Field devices such as actuators are used by the process control industry to remotely control physical parameters of a process, such as flow rate, temperature, etc. The process vari may be transmitted to a control room or to a control room from a field device such as a transmitter, to provide information about the process to a controller. A controller may then transmit control information to a field device such as an actuator, to modify a process parameter. For example, information related to pressure of a process fluid can be transmitted to a control room and used to control a process such as petroleum refining.

^^ Transmitters of process varis are used to verify process varis associated with fluids such as sludge, liquids, vapors and gases in chemical processing plants, pulp, oil, gas, pharmaceutical, food and other fluids. Process varis include pressure, temperature, flow, level, pH, conductivity, turbidity, density, concentration, chemical composition and other fluid properties. Process actuators include control valves, pumps, heaters, agitators, chillers, solenoids, vents and other devices for fluid control. A typical technique of the prior art for transmitting information involves controlling the amount of current flow through a process control loop. The current is supplied from a current source in the control room and the transmitter controls the current from its location in the field. For example, a 4 mA signal can be used to indicate a zero reading and a 20 mA signal can be used to indicate a full scale reading. More recently, transmitters have used digital circuits that communicate with a controller using a digital signal that overlaps the analog current signal flowing through the process control loop. An example of this technique is the HARTMR Hart Foundation communication protocol. The HARTMR protocol and other similar protocols typically include a set of commands or instructions that can be sent to the device in the field to produce a desired response, such as interrogation or control of the device. Fieldbus, another communications protocol, is proposed by the FoundationMR Fieldbus and is aimed at defining a communication layer or protocol to transmit information in a process control loop. The Fieldbus protocol specification is ISA-S50.01-1992, promulgated by the Instrument Society of America in 1992. Fieldbus is an industrial process communications protocol described in "Fieldbus Technical Overview Understanding FoundationTM fieldbus technology" (1998) avail from Rosemount Inc. in Eden Prairie, Minnesota. Some protocols compar with Fieldbus include Control Area Network (CAN = Controller Area Network), Lonworks and Profibus. In the Fieldbus protocol, the current flowing through the process control loop is not used to transmit an analog signal. On the contrary, all the information is transmitted digitally. In addition, the Fieldbus protocol allows field devices to be configured in a multi-bypass configuration, where more than one device in the field is connected in the same process control loop. The HARTMR protocol and more recently the Fieldbus protocol have been relatively effective in communicating process information about process control loops. Systems for process current control generally include many field devices and actuators coupled to a given process control loop, which in turn is coupled to a controller. It is convenient to provide process control information at a broad level to all the companies, such as through a company, such as through an entire company, the controller itself is coupled to a data network to everything company wide, such as an Ethernet data network, and the controller provides information regarding the process to the company. COMPENDIUM OF THE INVENTION The invention includes a process device that is adapted to be coupled to a process control loop and communicate with the process control loop. The communication in the process control loop is carried out according to an Internet protocol. A process communications device is also provided, which is adapted to couple to a process and Internet control loop. The process communication device provides control information kam ^ m? * l * naa? i process received from the process control loop to the Internet. In contrast, the process communication device also provides information received from the Internet to the process control loop. 5 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a system block diagram of a process control system, according to one embodiment of the invention. Figure 2 is a block diagram of system 10 of a process device according to one embodiment of the invention. Figure 3 is a cross-sectional view of a process device according to an embodiment of the invention. Figure 4 is a cross-sectional view of a process device according to one embodiment of the invention. Figure 5 is a cross-sectional view of a process device according to an embodiment 20 of the invention. Figure 6 is a flowchart of a sequence of process steps for implementing an embodiment of the invention with software. Figure 7 is a diagrammatic view of a data structure according to an embodiment of the ^^^ h¡ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Figure 8 is a system block diagram of a process communication device according to one embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Figure 1 is a system block diagram of the process control system 30 showing the environment of one embodiment of the invention. The process control system 30 includes process devices 32 coupled to a process communications device 34 via process control loop 36. The process communication device 34 is coupled to the computer 38 (also referred to as a node client 38) via communication link 40, Internet 42, and node link 44. Process communication device 34 can be placed in a control room such as control room 45 which can provide an intrinsic safety barrier in accordance with the STANDARD OF APPROVAL OF INTRINSICALLY INSURANCE AND ASSOCIATED EQUIPMENT FOR USE IN CLASS I, II AND III, DIVISION 1 HAZARDOUS SITES (CLASSIFIED), CLASS NUMBER 3610, (APPROVAL STANDARD) INTRINSICALLY SAFE APPARATUS AND ASSOCIATED APPARATUS FOR USE IN CLASS I, II AND III, DIVISION 1 HAZARDOUS (CLASSIFIED) LOCATIONS, CLASS NUMBER 3610) promulgated by Factory Mutual Research, October 1988. - < ..¿:: .., - .. > ? ..:.:, x: & .i, -, * ..-- -.; .-. m? atußßlmsmm e'- .:, .. s a.w MK ¡* - • - &&' > Faith &3 ?; Fluid processing environments are a special application for process devices such as transmitters and actuators, because vapors may be present in these environments that can be ignited by an electric spark that has enough energy to ignite the vapors. Accordingly, the communication conduits in the fluid processing environments are typically energy limited. Multiple redundant circuits are used to ensure that the energy levels in the ducts are below a safe energy level in such a way that they can not ignite flammable vapors, even under fault conditions. Transmitters and actuators are limited in energy. Ducts that pass through the safe area of the fluid processing environment to external equipment such as control room equipment typically pass through energy limiting barriers in such a way that a failure outside the fluid processing environment can not cause a spark inside the frequently explosive fluid processing environment. Conduits that have the potential for higher level signals that can spark under fault conditions are often not allowed to pass through or connect to equipment in a fluid processing environment. A typical Internet connection such as a communication link 40 or node link 44 in this manner is normally excluded from the fluid processing environment because its physical layer lacks the security features limiting electrical energy. In some cases, explosion proof housings and conduits are used to contain high energy or power circuits to provide energy limitation. Process devices are coupled to a process fluid container such as pipe 46, as illustrated in Figure 1. A process device is any device that already relates a signal to a process parameter or as a response effects a change in a process parameter. As such, the process devices 32 can be transmitters that detect a process variable such as pressure, temperature or level in a process vessel such as pipe 46. In addition, process devices 32 can also be actuators that control a variable of Process such as fluid flow or temperature, or a device that verifies the operation of a process or sends information related to the process in a process control loop. The process control loop 36 couples process devices 32 to the communications device of process 34 and can supply energization current to process devices 32. A process control loop can be any process control configuration where two or more conductors provide communication for devices in the loop. As such, the process control loop 36 can be a process control loop according to the process communication protocols such as the low speed Fieldbus protocol (Hl), the high speed Fieldbus protocol (H2), the HARTHR protocol or other convenient protocols that provide digital information transmission in a process control loop. The process communication device 34 is coupled to the communication link 40. The communication link 40 can be any appropriate data connection such as an Ethernet data connection (as defined by IEEE 802.3, promulgated by the Institute of Electrical and Electronic Engineers (Institute of Electrical and Electronic Engineers), or a point-to-point serial modem connection. As will be described later in greater detail, the process communication device 34 is adapted to communicate in the process control loop 36 and the communication link 40. As such, when the process communication device 34 receives data from the Link from to; > -.- &&• communication 40, the process communication device 34 places this data in the process control loop 36. In contrast, when the process communication device 34 receives data from the process control loop of two cables 36, the process communication device 34 places this data on the communication link 40. As can be seen in Figure 1, the communication link 40 is coupled to the Internet 42. The Internet 42 is any combination of two or more networks. data coupled together. For example, Internet 42 can be public Internet, or Internet 42 can also be an intranet across the width of a company, private. Internet 42 is coupled to client node 38 via node link 44. As with communication link 40, node link 44 can be any appropriate link, for example an Ethernet connection, or a serial point modem connection -a-point. As will be described in greater detail below in the specification, devices 32, 34, 38 are adapted for communication via the Internet. An example of this Internet adaptation includes the use of an Internet protocol suite known as Transmission Control Protocol / Internet Protocol (also referred to as TCP / IP (Transmission Control Protocol / Internet Protocol)). The Transmission Control Protocol / Internet Protocol is a known Internet protocol suite that is generally used for data communication over the public Internet. A Brief Tutorial of the TCP / IP Internet Protocol Suite can be obtained from Network Working Group as RFC 1180, published in January 1991. When devices 32, 34 and 38 are adapted for Internet communication using TCP / IP, the node Client 38 can access the process devices 32 to the send a request for process information to an Internet address of one or more process devices 32. Through known methods, the information request is eventually passed through the Internet to the process communication device 34. The device Process communication means 34 transforms the request into an appropriate form for transmission over the process control loop 36 and routes the request to the correct processing device according to destination information contained in the request. The request is received by the destination processing device 32, which provides by way of response, the process control information back to the client node 38 via the communication link 40, Internet 42, and node link 44 This information process control can be in accordance with the Protocol of "^^ - M-a * a ^ éfea» Hypertext transfer or any other convenient protocol. The Hypertext Transfer Protocol has been used by the global information initiative of World-Wide-Web since 1990. A specification reflecting the common use of this protocol can be obtained from the Network Working Group as RFC: 1945. The data in accordance with The Hypertext Transfer Protocol may include, for example, Hypertext Markup Language, Java programs, messages or Active X data. Those skilled in the art will appreciate from Figure 1 and this related discussion that process devices 32 can act as network servers to client node 38. In addition, client node 38 can access process devices 32 through industry standard network viewer software such as Internet Explorer which is available from Microsoft, Inc. Figure 2 is a system block diagram of the process device 48, according to one embodiment of the invention. The process device 48 may be a process variable transmitter or a process driver, depending on the type of transducer connected to the process device 48. Process variable transmitters are used to verify process variables associated with fluid such as sludge , liquids, vapors and gases in chemical processing plants, pulp, oil, gas, pharmaceutical, food and other fluids. Process variables include pressure, temperature, flow, level, pH, conductivity, turbidity, density, concentration, chemical composition and other fluid properties. Process actuators include control valves, pumps, heaters, agitators, chillers, vents and other devices for fluid control. The process device 48 includes a regulator circuit 68, communication circuits 67 including loop interface circuit 70, processor 66 and memory 62 circuits, and transducer circuit 63. The transducer circuit 63 is coupled to a transducer 65 that can already be part of process device 48, or external and connected by a short cable. The fluid transducer 65 transduces a property of a fluid as illustrated. The transducer 65 can be a detector or alternatively an actuator. A circuit, such as a loop interface circuit 70 can be any electrical configuration (hardware, software, or combination of the two) that is arranged to produce a given result. The regulating circuit 68 can be any circuits that convey energy to the various components of the process device 48, with energy received from the process control loop 72. The regulator circuit 68 is adapted to couple to the process control loop 72 to energize the process device 48 with energy received from process control loop 72. In fact, regulator circuit 68 can even fully energize all electrical components of process device 48. As such, regulator circuit 68 is coupled to the interface circuit of loop 70, the processor circuit 66 and the memory 62, to provide power to those respective circuits. The loop interface circuit 70 can be any circuit that is adapted for digital communication in a process control loop. Through the loop interface circuit 70, the process device 48 is adapted to couple to the process control loop 72 to send and receive loop signals to and from the process control loop 72. For example, if the process 48 will operate in accordance with one of the Fieldbus protocols, the loop interface circuit 70 is adapted to send and receive Fieldbus data packets in the process control loop 72. The memory 62 can be any structure that has more of a state, or may already be maintained permanently or selectively in any state such as electric, magnetic, etc. The memory 62 is operatively coupled to the processor circuits 66. The memory 62 may store process information, communication information, device status information or a sequence of program steps to be performed by the processor circuit 66. In addition, memory 62 may contain portions that provide random access, or read-only access. Additionally, the memory 62 can be electrically erasable, such as an electrically erasable programmable read-only memory (eepro). The memory 62 stores data representative of an Internet address for the process device 48. The process device 48 is adapted to transduce a fluid property and communicate process control information relating to the fluid property through an environment of fluid processing (Figure 1) to a remote site. The transducer circuit 63 is adapted to couple to the fluid transducer 65 and to couple a signal representing the fluid transduced property ao of the processor circuit 66, which passes it to the communication circuits 67. The communication circuits 67 are adapted to coupling to a limited energy communication conduit 72 that passes through the environment for fluid handling. The communication circuits communicate process control information related to the property of transduced fluid on the communication conduit. The memory 62 coupled to the communication circuits is adapted to store data representing a direction identifying the process device. The stored address data represents an Internet address and communication circuits communicate process control information together with data representative of the Internet address in a limited energy form to the energy limited communication conduit. The data stored in memory 62, which are representative of the Internet address can be stored as the Internet address itself, such as data pointing to the Internet address of the processing device stored in another device, or as data from which its address it can be computed, or another convenient way to store a representation of the address. This unique structure allows the process device 48 to communicate securely over the duct 72 in a limited energy form, including data representing the Internet address of the device 48. When the duct passes through an unprotected area, the The address is then directly available outside the fluid handling area to communicate with the Internet that does not have the energy limiting characteristics. The processor circuit 66 can be incorporated into discrete circuits, a microprocessor, a structure programmable logic or any other convenient device. The processor circuit 66 is operatively coupled to the loop interface circuit 70 and the memory 62. The processor circuit 66 may be adapted to receive a detector output from the transducer circuit 63 that is indicative of a process variable. The processor circuit 66 is adapted to send data to and receive data from the loop interface circuit 70, this data is suitable for Internet transmission. Figure 3 is a cross-sectional view of the process device 49 according to one embodiment of the invention. Process device 49 is a type of process device 32 (shown in Figure 1). The process device 49 can be constructed to be convenient in hazardous or noxious environments. As such, the process device can be intrinsically safe according to the intrinsic safety standard specified above or to exposure test, in accordance with STANDARD OF APPROVAL FOR REQUIREMENTS GENERAL ELECTRICAL EQUIPMENT PROOF OF EXPLOSION, (APPROVAL STANDARD FOR EXPL0SION-PR0OF ELECTRICAL EQUIPMENT GENERAL REQUIREMENTS) Class Number 3615, promulgated by Factory Mutual Research March 1989. In this way, this process device can be suitable for operation in hazardous environments. The processing device 49 includes the housing 50, which in cooperation with the covers 52 circumscribes the electronic components of the transmitter 56. The processing device 49 also includes the sensing unit 64, which is adapted to couple to a process and provides an output that it is related to a process variable. In some embodiments, the detector unit 64 may be arranged outside of the process device 49. The detector unit 64 may be any system that is coupled to a physical process and provides an electrical output that is related to a process variable. The detector unit 64 may include a process detector, such as a pressure detector, and detector circuits such as circuits 61 that can provide features such as signal linearization or the like. The detector unit 64 is coupled to the processor 66 of the electronic components of the transmitter 56. In one embodiment of the invention, at least a portion of data transferred between the processor circuit 66 and the loop interface circuit 70 is in accordance with the Protocol of Hypertext Transfer (Hypertext Transfer Protocol). In another embodiment of the invention, the memory 62 stores Internet address data that uniquely identifies the process device 49 on the Internet. The address data may comprise at least four data groups, wherein each group has at least eight bits. This address can be expressed with each group of bits corresponding to its decimal equivalent. For example, an Internet address may be 201.138.92.5 which may correspond to a computer with the name "Rosemount.com". It should be noted, however, that the Internet address may include additional address information such as the subnet mask address or the like. In this embodiment, the process device 49 is particularly useful in situations where the process control loop 72 has been adapted for Internet addressing. In this way, instead of having a loop source of process control and destination addresses, process control loop packets will have destination and source Internet addresses. In this case, the processor circuit 66 cooperates with the loop interface circuit 70 to selectively interact with a process control loop data packet having an Internet address corresponding to that stored in memory 62. A packet is a group of digital information such as a series of digital bits. In another embodiment of the invention, the memory 62 stores data according to the Hypertext Markup Language (HTML = Hypertext Markup Language). The memory 62 is coupled to the processor circuit 66 such that the processor circuit 66 selectively provides the Hypertext Markup Language (HTML = Hypertext Markup Language) of the memory 62 to the loop interface circuit 70. In this mode, the process control device 49 is useful for sending and receiving Hypertext Markup Language (HTML = Hypertext Markup Language) data to and from the process control loop 72. In still another embodiment of the invention, the processor circuit 66 is it adapts to format the detector output that is received from the detector unit 64 according to an Internet protocol. The Internet protocol can be any appropriate Internet protocol such as the Internet protocol as specified in RFC: 719, which is promulgated by the Internet Engmeepng Task Force in September 1981. The processor circuit 66 provides the output of the formatted detector on the Internet to the loop interface circuit 70 which then further formats the output of the detector formatted on the Internet for transmission over the process control loop 72. For example, the output of the detector may be a ÉÉM ^ ?? | ta ^ É? J »octet or word (byte) of digital information that is indicative of the process variable. The processor circuit 66 may then encapsulate the octet with additional digital information indicative of an Internet address to which the detector output byte (byte) will travel. The combination of data octet and Internet address can be considered as an Internet data packet that is provided by the processor circuit 66 to the loop interface circuit 70. The loop interface circuit 70 receives the data packet and formats the data packet for transmission over a process control loop 72, which for example may be a Fieldbus process control loop. As such, in this embodiment, the loop interface circuit 70 adds additional data to the Internet data packet to direct the Internet data packet in the process control loop 72. Figure 4 is a cross-sectional view of process device 74 according to another embodiment of the invention. The process device 74 is identical to the process device 49 (shown in Figure 3) except for the verification circuit 76 and similar components are similarly numbered. The verification circuits 76 can be any circuits that detect or determine the occurrence of an event and provide a signal referring to the occurrence. Verification circuits 76 are operably coupled with the detector system 64 and the processor circuit 66. In addition, the verification circuits 76 can also be coupled to the regulator circuit 68 to receive energy from the process control loop 72 through the regulator circuit 68. Verification circuits 76 check the output of the detector system 64, to determine the occurrence of an event such as a detector failure, alarm condition or the like. In response to the occurrence of the event, the verification circuits 76 cause the processor circuit 66 to generate an event data packet according to an Internet protocol for transmission in the process control loop 72. The event data packet it can be any body of digital information that is related to the event. The event data packet can be indicative of the event itself, the detector output or both. The event data packet may be in accordance with the Hypertext Transfer Protocol (HTTP). Additionally, the event data packet may be selected to cause a destination device such as a client node 38 (shown in Figure 1) to perform a poll on receipt of the event data packet. The event data packet can also be selected to cause another process device in the process control loop, or via the Internet, to perform an action, such as closing a valve. In addition, process circuits 66 can generate additional packets that report actions taken by the processor 66 in response to the event, and these report packets can be routed through the Internet to an alpha-numerical locator radio or the like. In one example, verification circuits 76 may determine that a detector has failed and provide a signal related to this occurrence in the processor 66. The processor 66 may then send commands to other process devices to enter a fail safe mode. The processor 66 can then send additional information to a locator radio, alerting a supervisor about the condition. Figure 5 is a cross-sectional view of the process device 80 according to another embodiment of the invention. The process device 80 includes some components that are similar or identical to components in the embodiments described above, and these components are similarly listed. The process device 80 includes the regulator 68, the loop interface circuit 70, the processor circuit 66, the memory 62, the Internet protocol circuit 84 and the transmission circuit 82. The loop interface circuit 70 is coupled to the Internet protocol circuit 84 which is also coupled to the transmission circuit 82. The transmission circuit 82 is coupled to the processor circuit 66. The processor circuit 66 is adapted to receive an output signal from the detector system 64, which is indicative of a process variable. The processor circuit 66 provides output data which for example may be indicative of the detector output signal. Additionally, the processor circuit 66 may be adapted to receive power data from the transmission circuit 82. The transmission circuit 82 is coupled to the processor circuit 66 to receive the output data from the processor circuit 66. The transmission circuit 82 also can provide the power data to the processor circuit 66. The transmission circuit 82 transforms the output data that is received from the processor circuit 66, into output segments that are provided to the Internet protocol circuit 84. On the contrary, the transmission circuit 82 also assembles power segments received from the Internet protocol circuit 84 into power data that is provided to the circuits , F ~ ^ m mm¿Mi? M processors 66. A segment of any data is passed between the transmission circuit 82 and the Internet circuit 84. The transmission circuit 82 can operate according to various transmission protocols such such as the Transmission Control Protocol (TCP) as defined in RFC 793, promulgated by the Internet Engineering Task Force, or the User Datagram Protocol (UDP) as defined in RFC 768, promulgated by Internet Engineering Task Forcé. In addition, the data exchanged between the transmission circuit 82 and the processor circuit 66 may be in any of a variety of convenient protocols such as the Hypertext Transfer Protocol, File Transfer Protocol (FTP = File Transfer).

Protocol), Simple Message Transfer Protocol (SMTP = Simple Message Transfer Protocol), Protocol Telnet, Simple File Transfer Protocol (SFTP) Simple File Transfer Protocol) or the Trivial File Transfer Protocol (TFTP = Trivial File Transfer Protocol). The Internet protocol circuit 84 is operatively coupled to the transmission circuit 82 and adapted to provide an output packet for each output segment that is received from the transmission circuit 82. An output packet generally comprises an output segment that is provides by the transmission circuit 82, data indicative of the transmission protocol used by the transmission circuit 82, and an Internet address to which the packet will travel. In this way, if the transmission circuit 82 uses the transmission control protocol (TCP) to create the output segments, the data packets will indicate this. The Internet protocol circuit 84 may be adapted to receive power packets from the loop interface circuits 70 and selectively provide power segments to the transmission circuit 82. This selection is based on verifying data in the power packets, to determine if the power packs have been formatted according to the same transmission protocol as that provided by the transmission circuit 82. If the power packs have thus been formatted, then the power segments corresponding to the power packs are provided. from the Internet protocol circuit 84 to the transmission circuit 82. The loop interface circuits 70 are adapted to generate process control loop signals in response to and based on receiving packets of output from the Internet protocol circuit 84. In addition, . ^. a & ^ Sw & loop interface circuits 70 may also be adapted to selectively provide power packs to the Internet protocol circuit 84 based on received process control loop signals. Although the present invention has been described with respect to process devices that provide detector information in a process control loop, those skilled in the art will appreciate that the present invention is equally applicable to process devices that receive information from the process loop. process control and in response to a physical change in a process. For example, in Figure 5, by replacing the detector system 64 with an actuator system such as a valve, it will allow the processor circuit 66 to provide digital output signals to the actuator system, thereby modifying a process variable. This substitution will essentially convert any of the process devices described above into process devices that physically affect a process. Furthermore, it is entirely within the scope of the present invention to provide a process device that not only detects a process variable but also affects a process variable. further, although the embodiments shown in Figures 2 to 5 are described with respect to individual circuits, this notation is simply provided for clarity. In this way, the present invention can be practiced by combining various modules in an application-specific integrated circuit or by implementing the various circuits in a microprocessor with software (software). Figure 6 is a block diagram of a sequence of program steps that can be implemented in the processor 66 to practice the invention. The sequence shown in Figure 6 illustrates how a processing device according to one embodiment of the invention acts as an Internet information server. Server operation begins when the processor receives a request for information as indicated in block 90. This request may come from a device such as client node 38 (shown in Figure 5) or from an internal device such as a synchronizer . Those skilled in the art will appreciate that if a synchronizer is employed, then the process device essentially pushes the process information to a destination device. In block 92, the processor determines what information is requested and accesses the requested information. For example, the request can be directed to obtain H | ^ | process control information, process device information or both. Block 92 is completed when the processor stores the necessary information in memory such as in memory 62 (shown in Figures 5 2-5). In block 94, the processor formats the requested information for transmission over the Internet. When a relatively large amount of information is to be transmitted, the information must be decomposed into discrete segments. In this case, the formatting will probably involve decomposing the requested data into segments such as those according to the Transmission Control Protocol. However, if the amount of information requested is sufficient small, other convenient protocols such as the User Datagram Protocol may be used. Block 94 is concluded when the processor stores the formatted information in memory along with an indication of what particular type of formatting protocol was used. After block 94, the processor executes the program stage shown in block 96. Specifically, additional information such as the Internet address of the target device (generally the requesting device) and an address Internet of the process device, they are stored in memory along with the requested information formatted. In step 98, additional information is accessed by the processor to determine the address of a process control loop of a communication device that will send the information to the Internet. This information is stored in memory together with a process control loop address of the process device (source address). In block 100, the processor provides the stored memory contents (formatted requested information, format type, Internet addresses, and loop directions or process control) to a loop interface module that interacts with the physical equipment to enter signals in the process control loop that correspond to the memory contents. Figure 7 is a block diagram of a data structure 102 according to one embodiment of the invention. The data structure 102 includes the data block 104, the transmission control protocol header 106, the Internet protocol header 108, and the process control loop header 110. The data structure shown in Figure 10 can be take various specific forms such as, when the data 104 comprises a combination of process information and Hypertext Markup Language (HTML) data; Transmission control protocol head 106 is in accordance with the User Datagram protocol; the IP 108 head is in accordance with the Internet Protocol; and the loop head 110 is in accordance with the Fieldbus protocol. In addition, data transduction can also be employed such as endpoint delimiter for the process control loop. Those skilled in the art will appreciate that a variety of combinations are possible with the invention. The data structure shown in Figure 7 is assembled in a process device before transmission in a process control loop, and is also received from a process control loop so that data 104 is extracted. , the data structure 102 may be in memory in a particular process device, in transit through a process control loop or in a memory of a process communication device. Figure 8 is a system block diagram of the process communication device 34 according to an embodiment of the invention. The process communication device 34 includes loop communication circuits 116, Internet communication circuits 120, memory 122 and power supply circuit 124. Loop communication circuits 116, adapt to couple to process control loop 126 to send and receive process control loop signals to and process control loop 126. It will be noted that process control loop 126 can be any appropriate process control loop 5 provides digital communication between devices in the process control loop. The loop communication circuits 116 are coupled to the memory 122 which contains data indicative of a loop address of the communication device 34 in the process control loop 126.

In this manner, the loop communication circuits 116 are able to determine when the process control loop data is routed to the process communication device 34, by comparing the loop address contained in memory 122 with the device information of the device. destination which receives the control loop 126. The process loop communication circuitry 116 are coupled to communication circuitry 120. Internet communication circuitry adapted Internet 120 to couple to the Internet via link Communication 40. The communication circuits of Internet 120 are coupled to memory 122, which contains data indicative of an Internet address of communication device 34. When the process communication device 34 is operated to transmit data from the control loop Process Internet 126, the communication circuit loop 116 receive a packet from the loop loop protocol process 126 containing the loop address of process communication device 34 as stored in the memory 122. circuits loop communication 116 are adapted to extract an Internet packet from the loop packet that is received from the process control loop 126. An Internet packet is any data body that includes Internet addressing data such as the address of the Internet. IP. The loop communication circuits 116 provide the Internet packet extracted to the Internet communication circuits 120, which format the packet for transmission through the link 40. The Internet communication circuits 120 then transmit the Internet packet formatted through the link 40 to the Internet where the 40 link is connected When the communication device process 34 works in the opposite direction, an Internet packet is formatted for transmission through link 40 arrives at the communication circuit Internet 120. The Internet communication circuits 120 extract the Internet packet from the data that is received from the link 40. The Internet communication circuits 120 then determine if the destination for the Internet package. < ? fÍSSÍ & |. AI ^ j ^ Jl ^ - ^ i ^ i ^, ^ £ ^ m Roger that is a control device that resides in a process control loop 126. If so process, the communication circuit Internet 120 passes the Internet packet to the loop communication circuits 116 which encapsulate the Internet packet with the addressing information of the process control loop and introduce the packet thus formatted into a process control loop 126 for transmission to the device of process control of destination. As can be seen in Figure 8, the communication device 34 also includes the power supply 124 which is adapted to couple the process control loop 126 to inject energy into the process control loop 126. The power supply 124 can coupled to a power source 128 which is external to the control loop 126. in some embodiments process of the invention, the packet format loop may be the same as the format of information received from link 40. for example, when the link 40 is according to the Ethernet data network and process control loop 126 is in accordance with high-speed Fieldbus (H2), the packets may be so similar that requires little reformatting, having. In this mode, the process communication device 34 still adapts the data by changing signal levels. In this way, although an Ethernet network may not be intrinsically safe, the process communication device 34 may affect the signal levels in a proportion such that an intrinsic safety compliance of the process control loop 126 is maintained. As can be seen , the present invention provides a variety of process devices, and a process communication device that allows individual process devices to serve as Internet communication devices. In this way, a transmitter according to the present invention can perform the function of a network server that allows a variety of users using different platforms to access transmitter data and receive process information. In addition, software updates can now be provided to process devices through the public Internet, thus reducing administrative effort. Additionally, users of the present invention when interacting through the Internet with the process devices can make process changes. As can also be appreciated, because the present invention employs traditional process control loops, the present invention can be practiced with intrinsically safe process control devices, without compromising compliance with intrinsic safety. The various modalities set forth herein may be implemented alone or in combination (s) as desired or appropriate. Although the present invention has been described with reference to preferred embodiments, persons skilled in the art will recognize that changes in form and detail can be made without departing from the spirit and scope of the invention. »** ^ dS ~ * ** - ** .-

Claims (26)

1. CLAIMS 1. A process device adapted to be coupled to a fluid process control loop, the device is characterized in that it comprises: loop interface circuits adapted to couple the process control loop to send and receive loop signals in the process control loop; processor circuits coupled to the loop interface circuit adapted to provide data compatible with the Internet, with the loop interface circuits for transmission over the process control loop; and a memory coupled to the processor and adapted to store data related to Internet communication.
2. 2. A process device adapted to be coupled to a fluid process control loop, the process device being characterized in that it comprises: loop loop circuits adapted to be coupled to the process control loop for sending and receiving loop signals to and from of the process control loop; processor circuits operatively coupled to the loop interface circuits and adapted to receive a detector output and provide data indicative of the detector output to the loop interface circuits for transmission over the process control loop; and a memory operatively coupled with the processor circuits, the memory is adapted to contain data according to the Hypertext Markup Language (HTML = Hypertext Markup Language).
3. 3. A process device adapted to couple a fluid process control loop, the process device is characterized in that it comprises: means for providing power to the process device with energy received from the process control loop; loop communication means to communicate in the process control loop; processing means coupled to the means for loop communication, to provide a detector output to the loop communication means; and memory means operatively coupled to the processor means to provide data to the processing means according to the Hypertext Markup Language (HTML = Hypertext Markup Language).
4. 4. A process device adapted to be coupled to a fluid process control loop, the process device is characterized in that it comprises: loop interface circuits adapted to be coupled to the process control loop, to send and receive loop signals ay of the process control loop; Process circuits operatively coupled to the loop interface circuits and adapted to receive a detector output, the processor circuits are adapted to provide data to and receive data from the loop interface circuits; a memory operatively coupled to the processor and adapted to store data; and wherein at least a portion of the data communicated between the processor and the loop interface circuits is in accordance with the Hypertext Transfer Protocol (HTTP = Hypertext Transfer Protocol).
5. 5. A process device adapted to be coupled to a fluid process control loop, the process device being characterized in that it comprises: a regulator circuit adapted to couple to the process control loop and energize the processor device with energy received from the process control loop; loop interface circuits adapted to couple to the process control loop to send and receive loop signals to and from the process control loop; processor circuits operatively coupled to the loop interface circuits, the processor is adapted to receive a detector output; a memory operatively coupled to the processor, the memory is adapted to contain an Internet address of the processor device; and wherein the loop interface circuits are configured to receive data packets from the process control loop containing the Internet address and to transmit data packets in the process control loop including the Internet frame.
6. 6. The process device according to claim 5, characterized in that the Internet address is an Internet Protocol address as 5 defined by RFC 791, promulgated by the Internet Engineering Task Force September, 1981.
7. 7. The process device according to claim 5, characterized in that the Internet address comprises at least four data groups, each The group comprises at least eight bits.
8. 8. A process device adapted to be coupled to a fluid process control loop, the process device is characterized in that it comprises: means for providing power to the process device 15 with energy received from the process control loop; means for storing an Internet address; and means to send and receive data containing the Internet address to and process control.
9. 9. A process device adapted to be coupled to a fluid process control loop, the process device being characterized in that it comprises: looped interface circuits adapted to be coupled to the process control loop for sending and receiving loop signals ay of the process control loop; circuits 25 processors operatively coupled with the circuits of loop interface, the processor circuits are adapted to receive a detector output and format the detector output according to an internet protocol and provide the detector output formatted to the loop interface circuits for transmission in the control loop of process.
10. 10. The process device according to claim 9, characterized in that the Internet protocol is the Internet Protocol (IP = Internet 10 Protocol) as defined by RFC 791, promulgated by the Internet Engineering Task Force, September 1981.
11. 11. A process device adapted to be coupled to a fluid process control loop, the process device is characterized in that it comprises: a 15 regulator circuit adapted to couple to the process control loop and energize the process device with energy that is received from the process control loop; loop interface circuits adapted to couple to the process control loop to generate signals 20 of process control loop, according to a process control loop protocol in response to receiving output packets, and selectively providing power packets, based on received process control loop signals; Internet protocol circuits that 25 are operatively coupled with the interface circuits of loop and adapted to provide the output packets to the loop interface circuits according to an Internet protocol and based on output segments received by the Internet protocol circuits, each output packet comprises the output segments, one Internet source address, an Internet destination address, and data indicative of the type of transport, the Internet protocol circuits are further adapted to receive the power packets from the loop interface circuits; transmission circuits operatively coupled to Internet protocol circuits and adapted to transform output data that is received by the transmission circuits in the output segments, and assemble the power segments received from the Internet protocol circuits into data from departure; and processor circuits adapted to receive a detector output, and provide the output data to the transmission circuits and receive power data from the transmission circuits.
12. The process device according to claim 11, characterized in that the transmission circuits transform data according to the Transmission Control Protocol as defined by RFC 793, promulgated by the Internet Engineering Task Force.
13. The process device according to claim 11, characterized in that the transmission circuits transform data in accordance with the User Datagram Protocol as defined by RFC 768, promulgated by the Internet Engineering Task Force.
14. 14. A program in a computer readable medium, characterized in that it comprises: a data access routine to obtain fluid process data; a formatting routine for formatting the fluid process data according to a transmission protocol; a routing routine to add an Internet destination address to the formatted data; and a looping formatting routine to add a process loop destination address to the formatted data and Internet address.
15. 15. A data structure incorporated in a fluid processing device, the data structure is characterized in that it comprises: a data field; a transmission control head; an Internet protocol header; and a process control loop head.
16. 16. A process device adapted to be coupled to a fluid process control loop, the process device is characterized in that it comprises: a regulator circuit adapted to couple to the process control loop and energize the process device with energy that is receives from the process control loop; loop interface circuits adapted to couple to the process control loop to send and receive loop signals to and from the process control loop; processor circuits that are operatively coupled with the loop interface circuits, the processor circuits are adapted to receive a detector output; and a memory coupled with the processor circuits and adapted to store instructions for execution on the processor circuits, the instructions comprise: an Internet formatting routine for formatting the output of the detector according to an Internet protocol; a loop formatting routine to additionally format the formatted Internet output for transmission in the process control loop; an output routine to cause the processor to provide the output of the formatted detector to the loop interface circuits for transmission in the process control loop.
17. 17. A process communication device adapted to be coupled to a fluid process control loop, the device is characterized in that it comprises: a memory adapted to contain data indicative of a device loop address and an Internet address of the device; Communication circuits ««? AtMtlto ^ * - ******** **. loop, coupled to the memory and adapted to communicate in the process control loop; Internet communication circuits, coupled to the loop and memory communication circuits and adapted to connect to the Internet to communicate over the Internet; and wherein the Internet communication circuits pass information received from the Internet to the loop communication circuits for transmission over the process control loop and the loop communication circuits pass the information received from the process control loop to the process control loop. Internet communication circuits for transmission over the Internet.
18. 18. A process device adapted to transduce a fluid property and communicate process control information regarding fluid property through a fluid processing environment to a remote location, the device is characterized in that it comprises: a transducer circuit adapted to fit between a fluid transducer and a signal representing the transduced fluid property; communication circuits adapted to couple to a limited energy communication conduit, through the fluid handling environment, communication circuits communicate process control information related to the property of transduced fluid on the communication conduit; a memory coupled to communication circuits, adapted to store data representing a direction identifying the process device; wherein the address is an Internet address and the communication circuits communicate process control information together with representative data of the Internet address in a limited energy form to the energy limited communication conduit.
19. 19. The process device according to claims 1, 2, 4, 9 or 18, and further characterized in that it comprises a regulator circuit adapted to couple to the process control loop and energize the process device with energy received from the process control loop.
20. 20. The process device according to claim 19, characterized in that the regulator energizes the entire process device with energy that is received from the process control loop.
21. The process device according to claims 1, 2, 3, 4, 5, 8, 9, 11, 16 or 17, characterized in that the fluid process control loop is a two process control loop. wires
22. 22. The process device according to claims 1, 2, 4, 5, 9, 11 or 16, characterized in that the processor circuits are incorporated in a -J microprocessor.
23. 23. The process device according to claims 1, 2, 3, 4, 5, 8, 9, 11 or 16, characterized in that the process device is 5 intrinsically safe.
24. 24. The process device according to claims 1, 2, 3, 4, 5, 8, 9, 11 or 16, characterized in that the process device is explosion-proof.
25. 25. In a process device for a fluid process control loop, a method for transmitting data in the fluid process control loop, the method is characterized in that it comprises: obtaining data related to a fluid process; format the data 15 for Internet transmission; format the data for transmission over the fluid process control loop; and enter the formatted data in the fluid process control loop.
26. 26. A process device adapted to In order to couple to a fluid process control loop, the process device is characterized in that it comprises: circuits adapted to carry out a method for transmitting data in the fluid process control loop, the method is characterized in that it comprises: obtaining 25 data related to a fluid process; format the ^ -Ssss lafc ^^ data for Internet transmission; format the data for transmission over the fluid process control loop; and enter the formatted data in the fluid process control loop.