WO2012000996A2

WO2012000996A2 - Method and system for starting up field devices, in particular hart field devices in the multidrop mode of operation

Info

Publication number: WO2012000996A2
Application number: PCT/EP2011/060822
Authority: WO
Inventors: Marc Fiedler
Original assignee: Endress+Hauser Process Solutions Ag
Priority date: 2010-07-01
Filing date: 2011-06-28
Publication date: 2012-01-05
Also published as: DE102010030821A1; WO2012000996A3

Abstract

The invention relates to a system (SB) for starting up field devices (F1 -F4), wherein said system can be connected to a voltage supply (PS), wherein the voltage supply (PS) is used to supply the field devices (F1 -F4) with electrical power, wherein the system (SB) comprises at least one starter circuit (S1), said starter circuit (S1) being used to disconnect at least one field device (F2) following a preceding one of the field devices (F1) according to a predetermined sequence of field devices (F1 -F4) from the voltage supply (PS) at least until the preceding field device (F1) receives a substantially constant current which is used to operate the preceding field device (F1) in a specific mode of operation.

Description

Method and device for commissioning field devices, in particular HART field devices

in multi-drop mode

The invention relates to a device for commissioning of field devices, which device can be connected to a power supply, wherein the power supply serves to the field devices with

to supply electrical energy.

Furthermore, the invention relates to the use of such a device.

In addition, the invention relates to a method for commissioning field devices, wherein the field devices to a power supply

be connected, the field devices by means of

Power supply to be supplied with electrical energy.

In process automation technology, field devices are often used to detect and / or influence process variables. A variety of such field devices is manufactured and sold by the company Endress + Hauser. In general, field devices in modern manufacturing plants via fieldbus systems (HART, Profibus, etc.) with higher-level units, e.g. Control systems or control units connected.

The digital communication between the field devices can be done, for example, by means of the HART protocol. Field devices that support the HART protocol, in short HART field devices, can be operated in multidrop operating mode. The field devices are connected in parallel and communicate with the help of a communication resistor, which in series with the

Power supply of the field devices is connected. An arrangement in which such HART field devices are connected together is e.g. from the

Publication US 2008/0040515 A1 become known. In multi-drop operation mode, the current consumption of the HART field devices is usually constant 4 mA. Is there a single supply source, which one on 20 A limited supply of mA can supply power, theoretically a maximum of five field devices could be operated in parallel at this source.

In practice, it is hardly possible at a switchable 4..20 mA voltage source to operate five field devices in parallel at the voltage source, since many field devices need more current (inrush current) than 4 mA at the start before entering the multidrop Switch operating mode and set a constant current of 4 mA. The sum of the inrush currents of only two HART field devices often exceeds the 20 mA available in the assumed case.

An analogous problem also arises for systems and field devices, which are designed, for example, according to the Profibus PA standard. In such Profibus field devices, by limiting the power supply, e.g. due to an Ex zone, the maximum current and therefore the number of

Field devices that can be connected to a voltage source, be limited. The same applies to field devices and systems designed according to the Foundation Fieldbus standard.

The invention is therefore based on the object, a start of several

Field devices, which are supplied together by a, in particular ström limited, power supply with electrical energy to

enable.

The object is achieved by a device, the use of the device and a method.

With regard to the device, the object is achieved in that the

Device comprises at least one starter circuit, which

Starter circuit serves to at least one according to a

predetermined order of the field devices on a previous field device following field device at least as long as from the

Disconnect power supply until the previous field device in the Substantially constant current consumes the operation of the

previous field device in a particular operating mode is used.

Due to the power supply, a supply voltage

be provided, which is used for operating the field devices, in particular for supplying the field devices with electrical energy. In the

Power supply may in particular also be a

current-limited power supply act, i. the maximum current that the power supply can provide is limited. In particular, by means of the power supply, the substantially constant electrical current can be provided which the field devices, in particular the preceding field device, receive in the specific operating mode. The field devices can be connected to a single power supply and supplied by this power supply with electrical energy. The order of the field devices can be specified by the order in which the field devices are connected to the device, for example, viewed from the power supply. The field device following the predetermined sequence on a preceding field device can then be disconnected from the power supply at least until the preceding field device receives a substantially constant current.

The recorded substantially constant electric current can, for example, to maintain certain functionalities, such as the detection of measured values, etc., of the field devices, in particular of the preceding

Field device, serve. In one embodiment of the invention, all field devices connected to the device, which have a specific operating mode with a substantially constant current consumption, can thus be transferred one after the other into this operating mode. After the preceding, in particular immediately preceding, field device or all preceding field devices operate in the operating mode and thus each have a substantially constant for operating in the

Having provided for certain operating mode power consumption, can also be the subsequent field device to the power supply

connected and / or so with the from the power supply to Supplied supply voltage are supplied. The

The subsequent field device can be started after all previous field devices, in particular the preceding field device has a substantially constant current consumption, and, for example, also in the

operating mode. The field devices can be started in this way successively or not simultaneously and thereby the commissioning of several field devices, especially in a ström limited power supply, done. In one embodiment of the device, the field devices, in particular by means of the starter circuit, parallel to one another

Supply line can be connected, which supply line is used to supply the field devices with a required for receiving the substantially constant current operating voltage. The order of the field devices can also be determined by the order in which the field devices are connected to the

Supply line, which is, for example, a two-wire current loop connected are specified. In particular, the order of the field devices according to the order in which the field devices, for example. From the

Power supply seen from the supply line

are connected, be given. To the field devices to the

To connect power supply, the field devices, for example, can be connected in parallel to a provided for this purpose supply line. By the starter circuit, this supply line can be extended, i. to be continued. For example. can be connected in parallel to the supply line by means of the device and / or the starter circuit to which the field devices are connected, the field devices. As a result, it is also possible to form a fieldbus system, for example, in a tree structure, via which the field devices are not only supplied with energy, but also

to be able to communicate. For example, on the substantially

constant current from the field devices in the particular

Operating mode is recorded, digital signals, the digital

Serving communication via the fieldbus system, be modulated. In one embodiment of the device, the starter circuit separates the at least one following field device, in particular after switching on the previous field device by means of the starter circuit, for a

predetermined period of time from the power supply. After the previous field device operates in the particular operating mode, the following field device can be connected to the power supply. The following field device may also be started after it is also connected to the power supply, i. be put into operation. By the

Disconnect from the power supply, the supply of the following field device with the supply voltage is interrupted, so that the following field device no electrical energy from the

Power supply comes, consumed.

In one embodiment of the device is in the

previous field device to that immediately according to

predetermined order on the subsequent field device previous field device.

In one embodiment of the device, the starter circuit disconnects the at least one following field device from the power supply at least as long, in particular as long, until the preceding field device receives a substantially constant current serving for the particular operating mode of the preceding field device.

In one embodiment of the device, the starter circuit disconnects the at least one following field device from the power supply until the preceding field device receives a substantially constant current serving for the particular operating mode of the preceding field device which exceeds or falls below a predetermined threshold value. Thus, the field device following the preceding field device can remain disconnected from the power supply until the current that can be provided by the power supply is sufficient to operate the previous field device on the one hand and to start, ie turn on, the next field device on the other hand. For this purpose, the device or the starter circuit can be designed by means of corresponding threshold values, up to their over- or

fall below the following field device disconnected from the power supply. The thresholds may be current values that are determined by a corresponding circuit with the current consumption of the

previous field device is compared.

In one embodiment of the device, the field devices are connected via a two-wire fieldbus system, in particular via a HART fieldbus system. The connection for communication between the field devices via the

Fieldbus system can be about the device, in particular the

Starter circuit, and / or preferably via the same supply line (s), which also serve to power the field devices.

In one embodiment of the device, communication takes place via the two-wire fieldbus system via digital signals. As already mentioned, for digital communication between the users of the fieldbus system, i. the field devices, the digital signals on the substantially

be modulated constant current. This can be done particularly preferably according to the HART protocol.

In one embodiment of the device is in the

previous field device preferably to a HART field device, which has a multidrop operating mode.

In one embodiment of the device, the field devices are HART field devices which have a multidrop operating mode, and the particular operating mode is the multidrop operating mode.

In one embodiment of the device, the starter circuit separates the at least one following field device at least as long from the

Power supply until the previous field device, in particular all according to the predetermined order the previous field device previous field devices in the multi-drop operating mode is or are. In one embodiment of the device, the starter circuit comprises a switch which serves to separate the at least one following field device from the power supply. In one embodiment of the device, the starter circuit is part of one of the field devices, in particular the first of the field devices.

In one embodiment of the device, the device and / or the starter circuit is carried out separately from the field devices, in particular accommodated in a separate housing. In this case, you can

in particular more of the starter circuits in a housing

be accommodated, and be contacted via terminals on the housing. As a result, a connection between the field burrs can also be connected by successively connected in parallel to the supply line

Starter circuits are carried out, wherein, for example, a field device can be connected to each starter circuit.

In one embodiment of the device, the starter circuit has two input-side terminals, which are for connecting the

Power supply serve. The input-side terminals can be used to connect the device via the connecting line with the

Power supply serve. In addition, the Eingangsseitgen

Connections of the device or the starter circuit also serve to connect the starter circuit with the previous field device and / or a previous, especially identical, starter circuit.

In one embodiment of the device, the starter circuit comprises two supply terminals, wherein the supply terminals are used for connecting the at least one preceding field device.

In one embodiment of the device, the starter circuit has two output-side terminals, via which the field device following the predefined sequence and / or a further starter circuit can be connected to the preceding field device. Both On the input side and / or output side terminals and / or in the supply connections may be, for example, to terminals.

In one embodiment of the device, the starter circuit has a measuring device, which serves the current consumption over the

Input side terminals, the output side terminals and / or to determine the supply terminals of the starter circuit.

In one embodiment of the device, the measuring device is used to determine the current consumption of the last field device started.

In one embodiment of the device, at least one transmitter is provided, which serves to control the switch, which serves to separate the following field device from the power supply.

In an embodiment of the device, the control of the switch is effected by the evaluation electronics as a function of the current consumption, in particular by means of the measuring device, via the input and / or output side connections and / or the supply connections. By means of the evaluation of the switch can be closed so that the output side terminals a voltage can be tapped or the switch can be opened so that between the

output side terminals no current can flow and therefore no voltage can be tapped.

Furthermore, the object is achieved by the use of the device and / or starter circuit according to one of the preceding claims for initialization, in particular for startup, a particular operating mode of a field device, in particular a multidrop operating mode of a HART field device.

With regard to the method, the object is achieved in that at least one according to a predetermined order of the field devices to a previous field device following the field device at least as long the power supply is disconnected until the previous field device receives a substantially constant current for a particular operating mode of the preceding field device. after the

Current consumption of the previous field device is substantially constant, the subsequent field device with the power supply

be connected and also put into operation, i. to be started.

In one embodiment of the method, the field devices, in particular by means of a starter circuit, parallel to one another

Supply line connected, via which supply line the field devices are connected to the power supply.

In one embodiment of the method, the field devices are put into operation in accordance with the predetermined sequence.

In one embodiment of the method, the subsequent field device is disconnected from the power supply as long as possible, in particular just as long, until the preceding field device receives a substantially constant current which operates to operate the preceding field device in a specific operating mode, in particular multidrop operation.

In one embodiment of the method, after the preceding field device operates in the multidrop operating mode, the following

Field device put into operation.

In one embodiment of the method, the current consumption of the preceding field device and / or at least part of the field devices is determined.

In one embodiment of the method, a switch, by means of which the following field device is disconnected from the supply voltage, is activated as a function of the determined current consumption. The invention is based on the principle of staggered starting of

Field devices. It is therefore u.a. a device and a method

proposed, which on the one hand to the, in particular current-limited, supply connection (eg., A wireless adapter) can be connected, is supplied by this and the other

Connected field devices sequentially starts until each of the currently started field device has switched to the specific operating mode and operates with a substantially constant current consumption. Then the next field device is started. If all connected field devices are in the intended operating mode, the field device bus can be scanned by command or automatically and all connected field devices can be detected. The field devices can then data with each other or with a higher-level control system or a corresponding

Exchange control unit within the field device bus.

The invention will be explained in more detail with reference to the following drawings. It shows:

1 shows a schematic representation of a first embodiment of the

Invention,

2 shows a schematic representation of a second embodiment of the invention, FIG. 3 shows an example of the time course of the current consumption of a

Field device after starting the field device, and

Fig. 4: a schematic representation of the invention in a third

Design.

FIG. 1 shows a first embodiment of the invention. As mentioned above, for example, HART field devices usually need a higher current for a certain time after being switched on than, for example, 4 mA (inrush current l (t), cf. FIG. 3). It can therefore at least one starter circuit S4, S5, S6 provided be that a supply terminal V1, V2, V3 for one of the field devices F2, F3, F4 only after a fixed time, which is greater than the start time of a previously started field device F1, F2, F3, connects to the power supply. For example. applies to the starting of the third field device F3, that the third field device F3 first supplied with the supply voltage and is therefore started after the time required for the second field device F2 to start, ie after the start time has elapsed. Likewise, the fourth field device F4 is first supplied with the supply voltage and thus started after the start time of the third field device F3 has elapsed.

In the embodiment according to FIG. 1, a, in particular switchable and current-limited 4..20 mA, voltage source PS is connected via a two-wire line 2L to the proposed device, a so-called starter box SB. The two-wire current loop 2L is connected to the input-side terminals E of the starter box SB. A first, second and third starter circuit S4, S5, S6 are integrated into the starter box SB and via the

Supply connections V1, V2, V3 can be contacted. About one

Supply connection V4 is the first field device F1 connected to the starter box. The first field device F1 is in the embodiment of Figure 1 via the supply terminals V4 directly to the input sides

Connections E of the device connected. The second field device F2, the third field device F3 and the fourth field device F4, however, are in each case via at least one starter circuit S4, S5, S6 with the input side

Connections E and thus the voltage source PS connected. The field devices F1, F2, F3, F4 are thus connected to the voltage source PS via the starter box SB or can be connected via the starter circuits S4, S5, S6. In this case, the field devices F1, F2, F3, F4 are parallel to each other

Two-wire current loop 2L connected.

Alternatively, the field devices F2, F3, F4 instead of the external starter box SB have a starter circuit, which is housed within the housing of the respective field device F2, F3, F4, and in particular in the operating electronics of the respective field device F2, F3, F4 is integrated. The starter circuits S4, S5, S6 can essentially consist in each case of at least one switching delay SV1, SV2, SV3, by which the respectively connected field device F2, F3, F4 is connected to the voltage source PS only after a predetermined delay time. The

Delay times of the starter circuits S4, S5, S6 are matched to one another such that a field device F2, F3, F4 connected to one of the starter circuits S4, S5, S6 is first connected to the voltage source PS when the preceding field device or the

previous field devices are already in the specific operating mode. In the case of HART field devices, this is, for example, the multidrop mode. For example, a HART field device following a preceding HART field device starts, for example, only when the preceding HART field device already has a substantially constant state in the multidrop operating mode

Current consumption of 4 mA works. The time that a field device, to start and / or to work in a particular operating mode needs, for example, can be specified by the manufacturer of the respective field device and the starter circuit or the Schaltverzogerer be adjusted accordingly. The start time of a field device can also be measured and the delay time set accordingly.

The Schaltverzogerer one, several or all of the starter circuit S4, S5, S6 connected field devices F2, F3, F4 can be triggered, for example, manually. Thus, for example, after all the field devices S2, S3, S4 to be put into operation are connected to the starter box SB, one or more or all of the switching delays SV1, SV2, SV3 are triggered, thereby starting the connected field devices one after the other.

Of course, in particular depending on the current limitation of the voltage source PS and the current consumption of the field devices, more than the four field devices F1, F2, F3, F4 shown in FIG. 1 can also be connected to the starter box SB and put into operation.

The field devices F1, F2, F3, F4 can in particular on the

Two-wire current loop 2L and the starter box SB also form a bus system, via which they exchange data with each other and / or with a control unit, not shown. The bus system can preferably also be put into operation after the field devices have been started, ie operate in a specific operating mode with a substantially constant current consumption.

Figure 2 shows another embodiment of the proposed invention. A starter circuit S1, S2, S3 independently recognizes here on the basis of the current consumption when the currently started field device F5, F6, F7 has reached a certain predetermined operating mode with a substantially constant current consumption, which serves to operate the field device, and then connects the corresponding one predetermined sequence of field devices subsequent field device with the power supply PS. The sequence of the field devices can be specified by the order in which the field devices are connected to the two-wire current loop 2L or in which the starter circuits, via which the field devices are connected to the two-wire current loop, are connected to one another. Since the embodiment according to Figure 2, in contrast to the

Embodiment according to Figure 1, regardless of a predetermined, possibly oriented at the start time of the respective field device delay time, but rather takes into account the actual current consumption of the field device connected to the starter circuit, the embodiment of Figure 2 represents a particularly preferred embodiment.

Also in the embodiment shown in Figure 2, the field devices F5, F6, F7 are connected to a current-limited power supply PS. Each of the field devices F5, F6, F7 has a starter circuit S1, S2, S3, by which the current consumption of the respective field device F5, F6, F7 is determined.

The structure of a starter circuit according to the embodiment in Figure 2 will be explained below with reference to one of the starter circuits. Thus, the starter circuit S2 has a plurality of terminals E2, B2, V6. The

Input-side terminals E2 can be connected to the Power supply PS or serve with a previous starter circuit S1, while the supply terminals V6 for connecting the

Field device F6, whose power consumption is to be monitored serve.

Furthermore, if necessary, output-side connections B2 are provided, which are provided for connecting the optionally following field device F7. The field device F6 whose current consumption is to be monitored, can for this purpose via the supply terminals V6 parallel to the other

Field devices F5, F7 and the 2-wire current loop 2L, which serves for the power supply. A measuring device ME2 for determining the current consumption of the field device F6 can be integrated in the starter circuit S2. The measuring device ME2 can, for example, between the two-wire current loop 2L and the

Supply terminals V6 for the field device F6 whose power consumption is to be monitored, be arranged. The starter circuit S2 may further comprise a control unit C2, which controls a switch W2. In addition, the measuring device ME2 may be connected to the control unit C2, it being possible to determine by the measuring device ME2 output to the control unit C2 whether the current consumption of the connected field device F6 is substantially constant, ie whether the field device F6 in the specific operating mode , is. Based on this, the switch W2 can be controlled by the control unit C2 to the subsequent field device F7 and the output side terminals B2 of the starter circuit S2, via which the subsequent field device F7 with the

Starter circuit S2 is connected to disconnect from the power source PS, so that via the output side terminals no supply voltage can be tapped. Furthermore, the switch W2 can then be used to connect the output-side terminals B2 to the voltage source PS and thereby supply the subsequent field device F7 with the supply voltage.

The proposed invention allows more than one field device to be operated on a current-limited feeding output of a voltage supply PS. This is particularly advantageous if the power supply PS is another device and this one supplying device has a, in particular unlimited, energy source and the field devices to be connected, which may be in particular HART field devices, locally localized close to each other. In practice this is the case, for example, with a wireless adapter connected to one or more field devices. Thus, for example, in a single tank / silo several sensors are needed, which are then connected without building a separate supply (loop) a single wireless adapter. The adapter itself can then be fed in such a case via a power supply or other high-capacity power source.

The starter circuits S1, S2, S3 can thereby, as shown in Figure 2, externally, i. be arranged outside of the respective field device and preferably housed together in a housing and so for example. Formed in the embodiment of Figure 4 starter box SB1 form. Alternatively, the starter circuits S1, S2, S3 can be located within the housing of the respective field device. Of course, more than the field devices F5, F6, F7 shown in FIG. 2 can also be connected to one another, in particular via the starter circuits S1, S2, S3.

Figure 3 shows the transient of the current waveform when a field device is turned on, i. the inrush current l (t). During a power up phase, a field device has a very nonuniform, i. fluctuating, current consumption, which assumes after a certain time, a value that is essentially predetermined by a certain operating mode and is used to operate the field device. The actual course of the current consumption can be approximated by an envelope H.

FIG. 4 shows a further embodiment of the present invention in the form of a starter box SB1. The starter box SB1 according to the embodiment in Figure 4 has two input-side terminals in the form of a first

Connection terminal A_IN, via which the starter box SB1 with the

Power supply PS is connectable. Furthermore, the starter box SB1 further terminals A1, A2, A3, A4, which is used for connecting Serve field devices. By way of example only one field device F8 is shown in FIG

connected. Of course, more than the four connection terminals shown can be provided for connecting field devices to the starter box SB1. The SB1 starter box then makes it easy to put the connected field devices into operation. To do this, the field devices are connected one after the other, one after the other, one after the other, after they have been connected to the starter box SB1.

LIST OF REFERENCE NUMBERS

PS power supply

SB starter box

SB1 starter box

F1 first field device

F2 second field device

F3 third field device

F4 fourth field device

F5 fifth field device

F6 sixth field device

F7 seventh field device

F8 eighth field device

51 first starter circuit

52 second starter circuit

53 third starter circuit

54 fourth starter circuit

55 fifth starter circuit

56 sixth starter circuit

A1 first connection terminal

A2 second connection terminal

A3 third terminal

A4 fourth terminal

A_IN Power supply terminal

I current

t time

l (t) Course of current consumption of a field device after the

turn on

mA milliamps

ME1 first measuring device

ME2 second measuring device

ME3 third measuring device

C1 first control unit

C2 second control unit C3 third control unit

W1 first switch

W2 second switch

W3 third switch

2L two-wire current loop

E1 input-side connections

SV1 first switching delay

SV2 second switching delay

SV3 third time delay

V1 first supply connection

V2 second supply connection

V3 third supply connection

B1 first output side connection

B2 second output side connection

B3 third output side connection

Claims

claims

1 . Device (SB) for commissioning field devices (F1 -F4),

which device can be connected to a power supply (PS), the power supply (PS) serving to supply the field devices (F1 -F4) with electrical energy,

characterized,

in that the device (SB) comprises at least one starter circuit (S1), which starter circuit (S1) serves at least one field device (F2) following a predetermined sequence of the field devices (F1-F4) at least as long as a preceding field device (F1) to disconnect from the power supply (PS),

until the preceding field device (F1) receives a substantially constant current which serves to operate the preceding field device (F1) in a specific operating mode.

2. Apparatus according to claim 1,

characterized,

the field devices (F1 -F4), in particular by means of the at least one starter circuit (S4-S6), can be connected in parallel to one another to a supply line (2L),

which supply line (2L) serves to supply the field devices (F1 -F4) with an operating voltage required for receiving the substantially constant current.

3. Device according to one of the preceding claims,

characterized,

the starter circuit (S4-S6) disconnects the at least one following field device, in particular after switching on the preceding field device by means of the starter circuit (S4-S6), for a predetermined period of time from the voltage supply (PS);

and or

that the starting circuit (S1 -S3) the at least one subsequent field device at least as long as, in particular just as long, from the Power supply (PS) disconnects until the previous field device receives a substantially constant current for the particular operating mode of the preceding field device;

and or

the starter circuit (S1 -S3) disconnects the at least one following field device from the power supply (PS) until the preceding field device receives a substantially constant current which serves for the particular operating mode of the preceding field device and which exceeds or falls below a predetermined threshold value.

4. Device according to at least one of the preceding claims,

characterized,

the field devices (F1 -F4) are connected via a two-wire fieldbus system (2L), in particular via a HART fieldbus system,

and or

that the field devices (F1 -F4) are HART field devices which have a multidrop operating mode, and

that the particular operating mode is the multidrop operating mode.

5. Device according to one of the preceding claims,

characterized,

in that the starter circuit (S4-S6) comprises a switch (SV1 -SV3; W1-W3) serving to connect the at least one following field device of the

Power supply (PS) to separate.

6. Device according to one of the preceding claims,

characterized,

the starter circuit (S4-S6) is part of one of the field devices (F2-F4), in particular of the first of the field devices (F1);

or

the device (SB, SB1) and / or the starter circuit (S4-S6) is implemented separately from the field devices (F1-F4), in particular accommodated in a separate housing.

7. Device according to one of the preceding claims,

characterized,

that the starter circuit (S1 -S3) has two input-side terminals (E1 -E3), which serve to connect the power supply (PS);

and or

the starter circuit (S1 -S3) comprises two supply terminals (V5-V7),

wherein the supply terminals (V5-V7) are for connecting the at least one preceding field device;

and or

the starter circuit has two output-side terminals (B1 -B3), via which the output to the previous field device according to the

predetermined order following field device and / or another

Starter circuit can be connected.

8. Device according to one of the preceding claims,

characterized,

the starter circuit (S1, S2, S3) has a measuring device (ME1, ME2, ME3), which serves to record the current consumption via the input-side connections (E1, E2, E3), the output-side connections (B1, B2, B3) and / or supply terminals (V5, V6, V7) of the starter circuit (S1, S2, S3);

and or

that the measuring device (ME1, ME2, ME3) serves, after switching on a field device (F5, F6, F7), by means of the starter circuit (S1, S2, S3), to determine the current consumption of the last field device started.

9. Device according to one of the preceding claims,

characterized,

that at least one evaluation (C1, C2, C3) is provided, which serves to control the switch (W1, W2, W3), which is used to disconnect the following field device from the power supply (PS);

and or in that the control of the switch (W1, W2, W3) is determined by the evaluation electronics (C1, C2, C3) as a function of, in particular by means of the measuring device (ME1, ME2, ME3)

Current consumption via the input side and / or output side

Connections (E1, E2, E3, B1, B2, B3) and / or the supply connections (V5, V6, V7) takes place.

10.Use of the device (SB, SB1) and / or starter circuit (S1, S2, S3) according to one of the preceding claims for initialization of a specific operating mode of a field device, in particular a multidrop operating mode of a HART field device.

1 1. Procedure for commissioning field devices (F1 -F4),

the field devices (F1 -F4) being connected to a power supply (PS)

be connected

wherein the field devices (F1 -F4) are supplied with electrical energy by means of the power supply (PS),

characterized,

at least one field device corresponding to a given sequence of the field devices is disconnected from the power supply (PS) at least as long as the field device next to it, until the preceding field device receives a substantially constant current serving for a specific operating mode of the preceding field device.

12. The method according to claim 1 1,

characterized,

in that the field devices (F1 -F4), in particular by means of at least one starter circuit (S4, S5, S6), are connected in parallel to a supply line (2L), via which supply line (2L) the

Field devices (F1 -F4) to be connected to the power supply (PS).

13. The method of claim 1 1 or 12,

characterized, that the field devices (F1 -F4) are put into operation according to the given order.

14. The method according to any one of claims 11 to 13,

characterized,

that the subsequent field device is disconnected from the power supply (PS) as long as possible, in particular just as long,

until the preceding field device receives a substantially constant current that operates to operate the previous field device in a particular operating mode, in particular multi-drop operation; and or

that after the previous field device is operating in the multidrop operating mode, the subsequent field device is put into operation;

and or

the current consumption of the preceding field device and / or at least part of the field devices is determined. 5. The method according to claim 14,

characterized,

a switch (W1, W2, W3), by means of which the subsequent field device is disconnected from the supply voltage or the power supply (PS), is activated as a function of the determined current consumption.