DE102006046243A1 - Field device and method for its commissioning and / or operation - Google Patents

Abstract

The invention relates to a field device and method for its commissioning and its operation, which allow an optimization of power consumption by the field device (3) via a data bus (5) to a higher-level unit (1) can be connected via the data bus ( 5) is energized and has an input circuit (7) and a separate circuit (9) separated therefrom, the input circuit (7) operating directly through the connection to the data bus line (5), to be connected to the data bus line (5) Bus terminal (11) and having a processor-controlled current control and wherein the residual circuit (9) via the input circuit (7) is energized and is put into operation by the input circuit (7).

Description

The The invention relates to a field device and method of commissioning and operation thereof.

In The automation and process control technology are many field devices used to measure process variables in the process flow (sensors) or controlling controlled variables (Actuators).

When example for Such sensors are commonly used in measurement and control technology used variety of different measuring devices, such. Pressure, temperature, Flow and / or level gauges to call. These field devices provide a measurement signal that corresponds to the measured value of the acquired process variables equivalent. This measurement signal is sent to a higher-level unit, e.g. a central control unit, such as e.g. a control room or a process control system, forwarded. As a rule, the entire process control takes place through the parent unit, where the measuring signals of various field devices are evaluated and due the evaluation control signals for Actuators are generated that control the process flow.

One example for an actuator is a controllable valve that controls the flow of a liquid or a gas through a pipeline section.

The signal transmission between field device and higher level Unit is usually done in digital form via a data bus. Known international standards for this signal transmission are PROFIBUS, FOUNDATION FIELDBUS or CAN bus.

The Control of the bus connection takes place with newer field devices, for example through microprocessors, ASIC's (application-specific intergrated circuits) or by freely programmable Logic circuits, e.g. FPGAs (field programmable gate arrays). The appropriate control program is in a non-volatile Memory in the field device is stored and executed in a microprocessor. It controls among other things the operating, measuring or control functions of the field device.

Become frequent Field devices over the Powered data bus. The current consumption of a field device depends on different factors. It is usually not constant over time. While the acquisition of the measured value requires an increased power requirement. In the meantime, a lower power consumption is sufficient. In conventional field devices the power consumption is set to a given hardware level Consumption value set, which covers the energy requirement of the field device. This consumption value usually corresponds to the peak load to ensure sufficient power supply to the field devices at all times. While the periods, where demand is below peak demand, it becomes unnecessarily high Electricity consumed. For field devices, the have an energy storage, a lower consumption value be set between the expected base load and the peak load is. If the energy storage is completely filled, so Here, too, more power is consumed than necessary.

Over a Data bus can only provide a certain amount of electricity become. This limits the number of field devices that can be connected to a data bus line. It is therefore desirable the power consumption of each connected to the data bus Field devices too optimize.

In the DE 1001 55 189 For this purpose, a method is described which allows a simple adjustment of the consumption values of the individual field devices adapted to the requirements by controlling the power supply of the respective field devices connected to a data bus line according to the current load of the data bus line. For this purpose, the power requirement of the individual connected field devices is determined, and the power utilization of the data bus is determined. Subsequently, control signals are sent via the data bus, which regulate the current consumption of the respective field devices as a function of the current load of the data bus. The data bus line supplies the power supply in each case for the entire field device and the power consumption is regulated in the field device, for example by adjustable resistors, field effect transistors or controllable current and voltage sources on the current consumption value. However, at all times, a minimum requirement that is sufficient for the basic supply of the entire field device must be made available via the data bus. When commissioning systems in which several field devices are connected to a data bus line and are supplied with power via them, the field devices are usually in an undefined operating state. If all connected field devices simultaneously record the operating current, this can lead to a break in the bus voltage at the moment of switch-on, especially in the case of power supply units limited in power. In addition, inrush currents often exceed the consumption currents required in normal operation. One reason for this is, for example, capacitors present in the field device, which are charged during commissioning. For example, this initial excessive power demand may cause fuses in segment couplers or Power supplies are triggered.

It It is an object of the invention to provide a field device and method for the same Commissioning and / or its operation indicate the one or the other Allow optimization of power consumption.

• – das über eine Datenbusleitung an eine übergeordnete Einheit anschließbar ist,
• – das über die Datenbusleitung mit Strom versorgt wird,
• – das eine Eingangsschaltung aufweist,
• – die unmittelbar durch den Anschluss an die Datenbusleitung in Betrieb geht,
• – die ein an die Datenbusleitung anzuschließendes Busterminal aufweist, und
• – die eine prozessor-gesteuerte Stromsteuerung aufweist, und
• – das eine Restschaltung aufweist,
• – die über die Eingangsschaltung mit Energie versorgt wird, und
• – die von der Eingangsschaltung in Betrieb genommen wird.

For this purpose, the invention consists in a field device

• - Which can be connected via a data bus to a higher-level unit,
• - which is powered by the data bus,
• Having an input circuit,
• - which goes directly into operation by the connection to the data bus,
• - Has a to be connected to the data bus line bus terminal, and
• - Which has a processor-controlled current control, and
• Having a residual circuit,
• - which is powered by the input circuit, and
• - which is put into operation by the input circuit.

• – die Eingangsschaltung an die Datenbusleitung angeschlossen wird,
• – die Eingangschaltung unmittelbar durch den Anschluss an die Datenbusleitung in Betrieb geht,
• – die Eingangsschaltung eine kurze zufällige Verzögerungszeit bestimmt, und
• – die Eingangsschaltung die Restschaltung nach Ablauf dieser Verzögerungszeit in Betrieb nimmt.

Furthermore, the invention consists in a method for starting up a field device according to the invention, in which

• The input circuit is connected to the data bus line,
• The input circuit goes into operation directly through the connection to the data bus line,
• The input circuit determines a short random delay time, and
• - The input circuit takes the remaining circuit after this delay time in operation.

• – die Eingangsschaltung an die Datenbusleitung angeschlossen wird,
• – die Eingangschaltung unmittelbar durch den Anschluss an die Datenbusleitung in Betrieb geht, und
• – die Eingangsschaltung die Restschaltung in Betrieb nimmt, wobei
• – die prozessor-gesteuerte Stromsteuerung einen hierzu über die Datenbusleitung zugeführten Anlaufstrom auf eine vorgegebene Obergrenze begrenzt.

Furthermore, the invention comprises a method for starting up a field device according to the invention, in which

• The input circuit is connected to the data bus line,
• - The input circuit goes directly through the connection to the data bus in operation, and
• - The input circuit takes the residual circuit in operation, where
• - The processor-controlled current control limits a supplied via the data bus line start-up current to a predetermined upper limit.

• – die Eingangsschaltung an die Datenbusleitung angeschlossen wird,
• – die Eingangschaltung unmittelbar durch den Anschluss an die Datenbusleitung in Betrieb geht, und
• – die Eingangsschaltung die Restschaltung in Betrieb nimmt, wobei
• – die prozessor-gesteuerte Stromsteuerung einen hierzu über die Datenbusleitung zugeführten Anlaufstrom langsam von Null auf einen Sollwert hochfährt.

Alternatively or additionally, the invention comprises a method for starting up a field device according to the invention, in which

• The input circuit is connected to the data bus line,
• - The input circuit goes directly through the connection to the data bus in operation, and
• - The input circuit takes the residual circuit in operation, where
• - The processor-controlled current control ramps up a supplied thereto via the data bus line start-up current slowly from zero to a desired value.

Of Furthermore, the invention consists in a method for commissioning and / or for operating a field device according to the invention, in which the processor-controlled Current control, the power consumption of the field device via the data bus to a limited upper limit.

In addition includes The invention relates to a method for operating a field device according to the invention the field device is put into a sleep mode at predetermined times, in which exclusively the input circuit is in operation. According to a variant terminates the Input circuit sleep mode after a predetermined time, by putting the remaining circuit back into operation.

• – die Eingangsschaltung eine Kommunikationseinheit umfasst, über die sie die Datenbusleitung abhört, und
• – die übergeordnete Einheit über die Datenbusleitung Zeiten vorgibt, zu denen das Feldgerät in den Sleep-Modus versetzt werden soll und Zeiten vorgibt, zu denen der Sleep-Modus beendet werden soll,
• – die Eingangschaltung diese Zeiten abhört und das Feldgerät zu diesen Zeiten in den Sleep-Modus versetzt bzw. den Sleep-Modus beendet.

Alternatively, the invention consists in a method for operating a field device according to the invention, in which

• The input circuit comprises a communication unit via which it listens to the data bus line, and
• The higher-level unit specifies times via the data bus line at which the field device is to be put into sleep mode and specifies times at which the sleep mode should be ended,
• - The input circuit listens to these times and put the field device in these times in the sleep mode or the sleep mode.

One An essential advantage of the invention is that the field device has an input circuit and a separate circuit therefrom. This is it possible exclusively to put the input circuit into operation and the times to those additionally the residual circuit is operated very free and flexible to choose. In order to assigns the field device at the times when only the input circuit In operation, a very low power requirement is on, which is significant below the minimum power requirement of conventional field devices, at at all times a minimum power requirement for the supply of the entire Field device via the data bus must be provided.

The Invention and further advantages will now be described with reference to the figures of Drawing in which an embodiment is shown, closer explained. Same Elements are provided in the figures with the same reference numerals.

1 shows a data bus system with multiple field devices; and

2 shows a block diagram of a field device according to the invention;

1 shows a schematic representation of a data bus system. It includes a parent unit 1 to which several field devices 3 via a data bus line 5 are connected. The parent unit 1 is, for example, a central control unit, such as a control room or a process control system. It is usually arranged in a control room, from which the entire process control takes place centrally. The field devices 3 As a rule, they are mounted decentralized to their respective locations.

With the field devices 3 are sensors and actuators. The sensors include, in particular, measuring devices, such as, for example, pressure, temperature, flow and / or level measuring devices, which supply a measuring signal which corresponds to the measured value of a detected process variable. This measuring signal is sent via the data bus to the higher-level unit 1 transfer. The actuators are field devices that control a controlled variable, eg valves.

The communication between the parent unit 1 and the field devices 3 occurs via the data bus 5 via internationally standardized transmission interfaces using special protocols such as PROFIBUS, FOUNDATION FIELDBUS or CAN bus.

2 shows a block diagram of a field device according to the invention 1 that's over the data bus 5 to the parent unit 1 is connectable, and via the data bus 5 is powered. In the illustrated field device 3 it is a sensor.

According to the invention, the field device 3 from an input circuit 7 and a connected residual circuit 9 , The input circuit 7 forms the connection of the field device 3 to the data bus. The from the input circuit 7 separate residual circuit 9 forms the functional unit of the field device 1 , which, depending on the field device type, serves, for example, for the measuring or control tasks of the field device 3 perform. In the case of a sensor, it comprises, for example, a sensor element for detecting a physical measured variable and associated measuring electronics, which receives, processes and / or evaluates the measured variables detected by the sensor element and converts them into a corresponding measuring signal, which then via a corresponding interface 10 the residual circuit 9 is available.

The field device 3 is via the input circuit 7 to the data bus 5 connected and powered. For this purpose, the input circuit 7 a bus terminal 11 on, to which the data bus line 5 is to be connected.

The input circuit 7 has a processor-controlled current control, which serves to the power consumption of the field device 3 to control. This includes an intelligent unit 13 , For example, a microprocessor, an ASIC's (application-specific intergrated circuits) or a freely programmable logic circuit, such as an FPGA (field programmable gate array). The corresponding control program is in a non-volatile memory in the field device 3 filed and is by the intelligent unit 13 executed. The intelligent unit 13 controls the power consumption via a current control, which in the illustrated embodiment, a control unit 15 and a controllable current source connected thereto 17 includes. This is the intelligent unit 13 via a control line 18 with the control unit 15 connected. The controllable current source 17 is via the bus terminal 11 from the data bus 5 fed. The latter takes place via two the bus terminal 11 with the power source 17 connecting connecting cables 19a . 19b , One of the connecting cables 19a over a connection 21 and corresponding input filters 23 to the intelligent unit 13 connected. The input circuit 7 immediately goes through the connection to the data bus 5 in operation. This is a concern of the bus voltage to the connecting cables 19a . 19b about the connection 21 captured and the intelligent unit 13 Runs a launcher, through which only the input circuit 7 goes into operation. The energy to be provided via the bus is in comparison to the energy requirement of the entire field device 3 very low, as this only the input circuit 7 needs to be supplied. Accordingly, the current consumption can be controlled by the processor-controlled current control to a very low starting value.

According to the invention, the residual circuit 9 from the input circuit 7 energized. The power supply takes place via the controllable current source 17 that the residual circuit 9 via a DC / DC converter 25 and a downstream of the intelligent unit 13 controlled switch 27 over which the residual circuit 9 is fed.

In addition, there is between the intelligent unit 13 the input circuit 7 and the residual circuit 9 a communication connection via the input circuit 7 with the residual circuit 9 communicated. In the illustrated embodiment, this communication takes place via the interface 10 ,

The commissioning of the residual circuit 9 is done by the power supply of the residual circuit 9 from the input circuit 7 provided. This is done in the illustrated embodiment via a corresponding control of the switch 27 through which the previously opened switch 27 is closed. In addition, via the interface 10 corresponding control signals to the residual circuit 9 be transmitted, for example, one in the residual circuit 9 start the process control. This makes it possible the residual circuit 9 targeted to put into different modes of operation. The operating modes include, for example, a sleep mode in which the residual circuit 9 is inactive, a normal operation in which the residual circuit 9 for example, performs periodic measurements and has a mean energy demand, or a peak operation in which, for example, measurements are carried out with a very high measuring rate and the residual circuit 9 has a very high energy requirement.

Preferably, the input circuit 7 one to the intelligent unit 13 connected communication unit 29 , Eg a modem, over which the communication of the input circuit 7 with the parent unit 1 he follows. The communication unit 29 is in the in 2 illustrated embodiment via a transmission control 31 with the control unit 15 connected to the power control and over the connection 21 and the input filters 23 to the connection line 19a connected. The input circuit 7 is thus able to listen to the bus and send information over the bus. Preferably, the entire communication of the field device takes place 3 with the parent unit 1 about this one communication unit 29 , In this case, the information to be transmitted includes both the information concerning the input circuit and the entire communication of the residual circuit 9 with the parent unit 1 , The latter takes place via the communication unit 29 and the interface 10 , The information to be sent then in particular includes the measurement results of the residual switching 9 , in measuring mode via the interface 10 to the input circuit 7 be transmitted.

Due to the division of the field device 1 in an input circuit 7 and a residual circuit 9 is a high degree of flexibility in terms of the energy requirements of the field device 1 whose advantages are explained in more detail with reference to the method described below for commissioning and operation of the field device according to the invention.

A great advantage of the field device according to the invention 3 is that by connecting the field device 3 to the data bus 5 initially only the input circuit 7 goes into operation. The energy requirement of the input circuit 7 is compared to the energy requirements of the entire field device 1 very low. Accordingly, the power source becomes the data bus line 5 fed is not overloaded even if very many field devices 1 at the same time to the data bus 5 be connected. A response of corresponding fuses in the segment couplers or power supply devices described above is thereby avoided.

Another advantage is that the times at which the associated residual circuits 9 the connected field devices 3 via the corresponding input circuits 7 be switched on very freely and flexibly selectable. This includes both automated commissioning procedures and the higher-level unit 1 or the input circuits 7 controlled procedure for commissioning feasible.

An example of an automated startup procedure is that the respective input circuit 7 to the data bus 5 is connected, and the respective input circuits 7 absorb their operation automatically by the voltage applied thereto. Then each determines to the data bus 5 connected input circuit 7 a short random delay time and takes the associated residual circuit 9 after expiry of this delay time in operation. This ensures that the individual residual circuits 9 automatically, ie without requiring appropriate communication over the bus, and operating at different times. This will provide power to the data bus 5 relieved during commissioning. In addition, it is ensured that even then no overload occurs when the individual residual circuits 9 have an excessive power consumption during the switch-on, since these increased consumption values burden the power supply at different times. However, this process must ensure that the power supply is sufficient at all times for the increased power consumption of at least one field device 1 even if all other field devices 1 already fully operational. It must therefore be considered, albeit small, energy buffer in the design of the supply.

Another advantage of the field device according to the invention is that the input circuit 7 having a processor-controlled current control. This makes it possible for the commissioning of the residual circuit 9 required starting current, via the data bus 5 must be made available to limit. Excessive energy consumption of the field devices 3 Accordingly, during the switch-on no longer occurs, and the energy buffer described above becomes superfluous.

In addition or as an alternative to the method described above, it is possible to proceed during commissioning in such a way that the respective input circuits 7 to the data bus 5 be connected, and first the input circuits 7 through the over the data bus 5 supplied operating voltage go into operation. The following are the respective residual circuits 9 through the associated input circuits 7 In operation, the processor-controlled current controls of the individual input circuits 7 for this purpose via the data bus 5 the respective field device 3 Limit supplied start-up current to a predetermined upper limit. The same applies of course to the operation of the field devices 3 , Also during operation of the field devices 3 is the current consumption of the respective field device 3 preferably limited by the processor-controlled current consumption to a predetermined upper limit.

In addition or as an alternative to the previously described methods, the input circuit 7 during commissioning of the field device 3 connected to the data bus and put into operation by applying the operating voltage, and then the residual circuit 9 put into operation, the processor-controlled current control a via the data bus 5 supplied starting current slowly ramps from zero to a predetermined setpoint.

Due to the subdivision of the field device 3 in input circuit 7 and residual circuit 9 the energy requirement of the individual can be connected to the data bus 5 connected field devices 3 make it very flexible and energy-saving even after commissioning. In particular, it is possible to reduce the power consumption of each field device 3 at given times or when needed to the very low energy requirements of the respective input circuit 7 to reduce.

This is preferably done by means of a method by which the respective field device 3 temporarily put in a sleep mode, in which only the input circuit 7 is in operation. For this example, for each of the data bus 5 connected field device 3 corresponding time windows are defined, which in the context of commissioning in corresponding memories in the respective field devices 3 be filed. In this case, for example, it is possible to proceed in such a way that the starting times to which the respective field devices 3 from the input circuit 7 be put into sleep mode during commissioning by the parent unit 1 are given and the respective input circuits 7 each of the sleep modes after a predetermined time implemented in the device stop in which they the associated residual circuit 9 start up again. This allows the power requirement of the field devices 3 , which is the sum of the power consumption of each connected field device 3 corresponds, reduce. Accordingly, more field devices can 3 to a single data bus 5 be connected, as is the case with conventional field devices. With conventional field devices, a minimum power requirement of each individual field device must be covered at all times, which must be sufficient for the energy supply of the entire field device. Alternatively, the energy savings achieved by the targeted displacement of individual field devices into the sleep mode can also be used to cover the peak demand of another to the same data bus line 5 connected field device 3 be used. This allows, for example, a specific time-limited increase in the measurement rate of individual field devices 3 without any energy bottlenecks, or the number of field devices that can be connected to the data bus 3 must be reduced.

This optimization of the power requirement can be made particularly flexible and needs-adapted if the input circuit 7 of the field device according to the invention 3 the communication unit described above 29 over which the input circuit 7 the data bus 5 listening. In this case, for example, the procedure is such that the higher-level unit 1 over the data bus 5 Times dictates to which the field device 3 should be put into sleep mode and times, at which the sleep mode should be terminated. The input circuit 7 hears these times over the data bus 5 and puts the field device in sleep mode at these times or terminates the sleep mode accordingly.

In addition, there is the communication unit 29 the possibility of time windows for further operating modes of the residual circuit 9 , For example, a normal operation or a peak operation with increased measurement rate to specify and the upper limits for the set by the processor-controlled power control current consumption of the field device 3 over the data bus 5 flexible, adapted to requirements and, if necessary, time-dependent. Providence of the communication unit 29 means in comparison to conventional field devices no additional overhead, since even with conventional field devices communication between field device and higher-level unit is provided to transmit, for example, recorded by the field device measurement results from the parent unit or to receive control signals via the data bus. The peculiarity consists in the field device according to the invention therein, the Kom munikationseinheit 29 in the input circuit 7 to arrange. This allows the input circuit 7 even then with the parent unit 1 communicate when the residual circuit 9 not in operation.

The residual circuit 9 is preferably in the illustrated embodiment by opening the switch 27 put into sleep mode. This sleep mode corresponds to switching off the residual circuit 9 , This ensures that the residual circuit 9 no energy consumed in sleep mode. Alternatively, the residual circuit could 9 be put into a sleep mode by appropriate hardware and software, which corresponds to a classic stand-by operation. In that case, the residual circuit needs 9 during stand-by operation one, albeit very small, power supply and it must be in the input circuit 7 Procedures are implemented by which the residual circuit 9 is placed in this state, or by this state is terminated.

1

parent unit

3

field device

5

data bus

7

input circuit

9

rest circuit

10

interface

11

bus Terminal

13

intelligent unit

15

control unit

17

power source

18

control line

19a

connecting cable

19b

connecting cable

21

connection

23

input filter

25

DC / DC converter

27

switch

29

communication unit

31

transmission control

Claims (8)

Field device ( 3 ) - that via a data bus line ( 5 ) to a higher-level unit ( 1 ) can be connected, - via the data bus ( 5 ) is supplied with power, - that an input circuit ( 7 ), which is directly connected to the data bus line ( 5 ) goes into operation, - the one to the data bus ( 5 ) to be connected bus terminal ( 11 ), and - which has a processor-controlled current control, and - which has a residual circuit ( 9 ), - via the input circuit ( 7 ) is energized, and - that of the input circuit ( 7 ) is put into operation. Method for commissioning a field device ( 3 ) according to claim 1, wherein - the input circuit ( 7 ) to the data bus line ( 5 ), - the input circuit ( 7 ) directly by the connection to the data bus line ( 5 ) goes into operation, - the input circuit ( 7 ) determines a short random delay time, and - the input circuit ( 7 ) the residual circuit ( 9 ) after expiry of this delay time. Method for commissioning a field device ( 3 ) according to claim 1, wherein - the input circuit ( 7 ) to the data bus line ( 5 ), - the input circuit ( 7 ) directly by the connection to the data bus line ( 5 ) goes into operation, and - the input circuit ( 7 ) the residual circuit ( 9 ), in which - the processor-controlled current control for this purpose via the data bus ( 5 ) limited starting current to a predetermined upper limit. Method for commissioning a field device ( 3 ) according to claim 1, wherein - the input circuit ( 7 ) to the data bus line ( 5 ), - the input circuit ( 7 ) directly by the connection to the data bus line ( 5 ) goes into operation, and - the input circuit ( 7 ) the residual circuit ( 9 ), in which - the processor-controlled current control for this purpose via the data bus ( 5 ) slowly ramps up from zero to a setpoint. Method for commissioning and / or operating a field device ( 3 ) according to claim 1, wherein the processor-controlled current control the power consumption of the field device ( 3 ) via the data bus line ( 5 ) is limited to a predetermined upper limit. Method for operating a field device ( 3 ) according to claim 1, wherein the field device ( 3 ) is put into a sleep mode at predetermined times, in which only the input circuit ( 7 ) is in operation. Method for operating a field device according to Claim 6, in which the input circuit ( 7 ) the sleep mode after a predetermined time ended, in which the residual circuit ( 9 ) starts up again. Method for operating a field device ( 3 ) according to claim 6, wherein - the input circuit ( 7 ) a communication unit ( 29 ), over which they connect the data bus line ( 5 ), and - the higher-level unit ( 1 ) via the data bus line ( 5 ) Times, to which the field device ( 3 ) is to be put into sleep mode and specifies times when the sleep mode should be ended, - the input circuit ( 7 ) listens to these times and the field device ( 3 ) put into sleep mode at these times or ended the sleep mode.