Method for the emergency shutdown of a bus system, and bus system

Abstract

In a method for the emergency shutdown of a bus system, and a bus system, having a master module and bus subscribers disposed in series, the master module and the bus subscribers sending data packets to one another with the aid of a data line, the method has the temporally consecutive method steps: in a first method step, a bus subscriber and/or the master module detect(s) an error status, in a second method step, the bus subscriber and/or the master module send(s) an emergency signal to all bus subscribers and to the master module, in a third method step, a further bus subscriber receives the emergency signal, immediately forwards it to an adjacent bus subscriber and simultaneously evaluates it, and in a fourth method step, the further bus subscriber shuts itself down automatically.

Claims

1. A method for emergency shutdown of a bus system, having a master module and serially-arranged bus subscribers adapted to send data packets to each other via a data line, comprising: detecting an error status by a bus subscriber and/or the master module; after the detecting, transmitting, by the bus subscriber and/or the master module, an emergency signal to all bus subscribers and to the master module; after the transmitting, receiving the emergency signal by a further bus subscriber and immediately forwarding, by the further bus subscriber, the emergency signal to an adjacent bus subscriber, the further bus subscriber evaluating the emergency signal simultaneously with the forwarding; and after the receiving, automatically shutting down the further bus subscriber.

2. The method according to claim 1, further comprising interrupting a data packet by the emergency signal.

3. The method according to claim 2, further comprising discontinuing transmission of the interrupted data packet and discarding the interrupted data packet.

4. The method according to claim 1, wherein all data packets have an identical length and/or signal length, a length and/or signal length of the emergency signal being shorter than the length and/or signal length of the data packets.

5. The method according to claim 1, wherein two successive data packets are temporally spaced by a transmission pause, the emergency signal interrupting a transmission pause.

6. The method according to claim 1, wherein the bus system has two data lines, the bus subscriber and/or the master module transmitting the emergency signal simultaneously via the two data lines.

7. A bus system, comprising: a master module and bus subscribers arranged in series; and at least one data line connecting the master module and the bus subscribers; wherein the bus system is adapted to perform a method for emergency shutdown of the bus system, the method including: detecting an error status by a bus subscriber and/or the master module; after the detecting, transmitting, by the bus subscriber and/or the master module, an emergency signal to all bus subscribers and to the master module; after the transmitting, receiving the emergency signal by a further bus subscriber and immediately forwarding, by the further bus subscriber, the emergency signal to an adjacent bus subscriber, the further bus subscriber evaluating the emergency signal simultaneously with the forwarding; and after the receiving, automatically shutting down the further bus subscriber.

8. The bus system according to claim 7, wherein the data line includes at least one first data line and at least one second data line.

9. The bus system according to claim 8, wherein the master module is adapted to transmit a data packet to the bus subscribers via the first data line and/or at least one bus subscriber is adapted to transmit a data packet to the master module via the second data line.

10. The bus system according to claim 7, wherein each data line includes at least one data cable, each bus subscriber being connected by a respective data cable to an upstream and/or downstream bus subscriber and/or to the master module.

11. The bus system according to claim 10, wherein each data cable includes two mating plug connector parts, each bus subscriber having a first plug connector part adapted to connect to a respective upstream bus subscriber and a second plug connector part adapted to connect to a respective downstream bus subscriber.

12. The bus system according to claim 10, wherein an individual data cable of the first data line and an individual data cable of the second data line are arranged between two adjacent bus subscribers in a cable sheath surrounding and/or enveloping the data cables in a circumferential direction.

13. The bus system according to claim 12, wherein a supply line and/or a ground lead for the bus subscribers are arranged in the cable sheath.

14. The bus system according to claim 7, wherein each bus subscriber includes a switch connected to a respective data line and adapted to interrupt data transmission along the respective data line.

15. The bus system according to claim 7, wherein each bus subscriber includes a time-measurement device.

16. The bus system according to claim 7, wherein each bus subscriber includes a logic circuit adapted to evaluate data packets of the master module and/or the bus subscribers.

17. The bus system according to claim 16, wherein the logic circuit is adapted to identify the emergency signal and, simultaneously with further evaluation of the emergency signal, to forward the emergency signal to an adjacent bus subscriber.

18. The bus system according to claim 7, wherein each bus subscriber includes an electronic circuit having: (a) a switch connected to a respective data line and adapted to interrupt data transmission along the respective data line, (b) a time-measurement device, and/or (c) a logic circuit adapted to evaluate data packets of the master module and/or the bus subscribers.

19. The bus system according to claim 18, wherein the switch, the time-measurement device, and/or the logic circuit are integrated into the electronic circuit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view of a bus system according to an example embodiment of the present invention.

(2) FIG. 2 shows the time characteristic of data packets (3, 4) on a data bus.

(3) FIG. 3 shows the time characteristic of data packets (3, 4) and an emergency signal on the data bus in a first case example.

(4) FIG. 4 shows the time characteristic of data packets (3, 4) and an emergency signal on the data bus in a second case example.

DETAILED DESCRIPTION

(5) The bus system according to an example embodiment of the present invention has a master module M and bus subscribers (S1, S2, S3, S4), which are disposed in series and connected to one another. The bus system has a first bus subscriber S1 disposed downstream from master module M. The bus system has a second bus subscriber S2 disposed downstream from first bus subscriber S1, first bus subscriber S1 being situated upstream from second bus subscriber S2. Second bus subscriber S2 is disposed upstream from a third bus subscriber S3, and third bus subscriber S3 is situated downstream from second bus subscriber S2. Third bus subscriber S3 is disposed upstream from a fourth bus subscriber S4, and fourth bus subscriber S4 is disposed downstream from third bus subscriber S3.

(6) A bus subscriber (S1, S2, S3, S4) situated downstream from another bus subscriber (S1, S2, S3, S4) is situated at a greater distance from master module M than the other bus subscriber (S1, S2, S3, S4) in the direction of the series arrangement. The other bus subscriber (S1, S2, S3, S4), which is disposed at a shorter distance from master module M than the bus subscriber (S1, S2, S3, S4) in the direction of the series arrangement, is located upstream from the bus subscriber (S1, S2, S3, S4).

(7) For example, the bus system is an industrial plant that has various devices as bus subscribers (S1, S2, S3, S4), such as drives or electronic components, e.g., drive converters for electric motors.

(8) The data bus has a first data line 1 and a second data line 2, which in each case serially connect the bus subscribers (S1, S2, S3, S4) and master module M to one another.

(9) With the aid of first data line 1, master module M sends data packets (3, 4) such as control commands to the bus subscribers (S1, S2, S3, S4). With the aid of second data line 2, the bus subscribers (S1, S2, S3, S4) send data packets (3, 4) such as status information to master module M.

(10) Each bus subscriber (S1, S2, S3, S4) has a first interface and a second interface, which are, for example, arranged as plug connector parts in each case. Each data line (1, 2) has at least one data cable. Each data cable has a first mating plug connector part and at least one second mating plug connector part for a data transmission between the bus subscribers (S1, S2, S3, S4) along the respective data line (1, 2).

(11) As a result, each bus subscriber (S1, S2, S3, S4) is able to be connected to a second plug connector part of an upstream bus subscriber (S1, S2, S3, S4) using a first plug connector part and the respective data cable, and is able to be connected by a second plug connector part and the respective data cable to a first plug connector part of a downstream bus subscriber (S1, S2, S3, S4).

(12) The respective data cable of first data line 1 and the respective data cable of second data line 2 may be guided in a shared cable sheath. A supply line and/or a ground lead for the bus subscribers (S1, S2, S3, S4) may be disposed in this cable sheath as well.

(13) Each bus subscriber (S1, S2, S3, S4) has a switch, in particular an electronic circuit, which is connected to the respective data line (1, 2). The switch may be used to interrupt the data transmission along the respective data line (1, 2).

(14) Each bus subscriber (S1, S2, S3, S4) has a time-measurement device, in particular a timer. The time-measurement device may be integrated into the electronic circuit of the bus subscriber (S1, S2, S3, S4).

(15) Using the electronic circuit, the data transmission along the respective data line (1, 2) is therefore able to be interrupted after a predefined time has elapsed.

(16) Each bus subscriber (S1, S2, S3, S4) has a logic circuit. The logic circuit may be integrated into the electronic circuit of the bus subscriber (S1, S2, S3, S4).

(17) Using the logic circuit, data packets on the data bus are able to be evaluated, and the sender of a data packet, in particular, is identifiable.

(18) In the event that a bus subscriber (S1, S2, S3, S4) is inactive, a data packet (3, 4) is forwarded without interruption and without a time delay through the inactive bus subscriber (S1, S2, S3, S4) to the downstream or upstream bus subscriber (S1, S2, S3, S4). A data packet (3, 4) passes through an inactive bus subscriber (S1, S2, S3, S4) without obstruction.

(19) The data bus may be implemented in a digital form.

(20) For the initialization of the bus system, master module M sends a request to log in to master module M to the bus subscribers (S1, S2, S3, S4) situated downstream. An active bus subscriber (S1, S2, S3, S4) disposed downstream from master module M logs in to master module M and forwards the request for the login to master module M to bus subscribers (S1, S2, S3, S4) downstream from it. The logged in bus subscriber (S1, S2, S3, S4) then waits for a predefined period of time to see whether a bus subscriber (S1, S2, S3, S4) downstream from it logs in to master module M.

(21) If no downstream bus subscriber (S1, S2, S3, S4) logs in to the master module, then the last logged in bus subscriber (S1, S2, S3, S4) closes the bus system as soon as the predefined period of time has elapsed, by connecting first data line 1 and second data line 2 to each other, in particular short-circuiting them. A data packet (3, 4) that is transmitted with the aid of first data line 1 from master module M to the bus subscribers (S1, S2, S3, S4) is thus forwarded to second data line 2 at the final bus subscriber (S1, S2, S3, S4) and routed back to the master module.

(22) The last bus subscriber (S1, S2, S3, S4) is the particular bus subscriber (S1, S2, S3, S4) that logs in last to master module M and has no active downstream bus subscribers (S1, S2, S3, S4).

(23) The request to log in to master module M is routed through an inactive bus subscriber (S1, S2, S3, S4) without this subscriber itself logging in to master module M.

(24) After the bus system has been closed, a release is granted by a superordinate control or by an operator and the bus system begins its operation.

(25) In the event that a bus subscriber (S1, S2, S3, S4) logs in late, i.e. after the predefined period of time following the login of the last bus subscriber (S1, S2, S3, S4) has elapsed, then this bus subscriber (S1, S2, S3, S4) sends a data packet (3, 4) to master module M. If a release has already been granted, this data packet (3, 4) is stopped by an upstream bus subscriber (S1, S2, S3, S4) that is logged in to master module M and is not forwarded to master module M.

(26) As soon as the release has been revoked, a data packet (3, 4) of the late bus subscriber (S1, S2, S3, S4) is forwarded to master module M and the late bus subscriber (S1, S2, S3, S4) is admitted to the bus system.

(27) In the event that the late bus subscriber (S1, S2, S3, S4) has no downstream bus subscribers (S1, S2, S3, S4) that are logged in to master module M, then it becomes the new last bus subscriber (S1, S2, S3, S4) and closes the bus system after waiting out the predefined period of time for the login of a bus subscriber (S1, S2, S3, S4).

(28) The predefined period of time for the login of a bus subscriber (S1, S2, S3, S4) is able to be adapted to the bus subscribers (S1, S2, S3, S4). The period of time may be selected such that bus subscribers (S1, S2, S3, S4) that have a longer initialization time are securely logged in to master module M.

(29) During the initialization of the bus system, bus addresses for the bus subscribers (S1, S2, S3, S4) are assigned automatically. For this purpose, master module M sends the bus address “1” to first bus subscriber S1. First bus subscriber S1 logs in to master module M using this bus address and increments the bus address by 1 and forwards it to its downstream bus subscriber (S1, S2, S3, S4). The downstream bus subscriber (S1, S2, S3, S4) logs in to master module M using the incremented bus address, i.e. bus address “2” in this instance, increments this bus address by 1 again and forwards it to the bus subscriber (S2, S3, S4) downstream from it.

(30) In an effort to restrict the number of bus subscribers (S1, S2, S3, S4) in the bus system, a bus subscriber (S1, S2, S3, S4) assigned a bus address that is greater than the maximally allowed number of bus subscribers (S1, S2, S3, S4) will not further increment this bus address but forwards the same bus address to its downstream bus subscriber (S1, S2, S3, S4), which uses this bus address to log in to master module M. As soon as master module M receives a bus address that is greater than the maximally allowed number of bus subscribers (S1, S2, S3, S4), master module M aborts the initialization of the bus system and transmits an error report to a control superordinate to master module M.

(31) If a bus subscriber (S1, S2, S3, S4) that is not yet active, i.e. an inactive bus subscriber (S1, S2, S3, S4), receives a bus address from a bus subscriber (S1, S2, S3, S4) upstream from it or from master module M, then this bus address is looped through the inactive bus subscriber (S1, S2, S3, S4) without being incremented, and assigned to a downstream bus subscriber (S1, S2, S3, S4).

(32) FIGS. 2 through 4 show the time characteristic of data packets 3 that are transmitted with the aid of a respective data line (1, 2). Each data packet 3 has a predefined length that is a function of the number of bus subscribers (S1, S2, S3, S4) of the bus system.

(33) The data transmission is interrupted for a predefined period of time between two temporally successive data packets 3, which means that two temporally successive data packets 3 are temporally spaced apart with the aid of a transmission pause 6.

(34) As soon as a bus subscriber (S1, S2, S3, S4) or master module M detects an error, data packet 4 transmitted at that instant is immediately interrupted and an emergency signal 5 is transmitted by the respective bus subscriber (S1, S2, S3, S4) or by master module M, as illustrated in FIG. 3. This emergency signal 5 causes an immediate shutdown of all bus subscribers (S1, S2, S3, S4).

(35) The interrupted data packet 4 is immediately terminated and not further processed by the bus subscribers (S1, S2, S3, S4).

(36) If a bus subscriber (S1, S2, S3, S4) or master module M detects an error during a transmission pause 6, then transmission pause 6 will be interrupted and an emergency signal 5 be sent by the respective bus subscriber (S1, S2, S3, S4) or by master module M, as illustrated in FIG. 4. This emergency signal 5 causes an immediate shutdown of all bus subscribers (S1, S2, S3, S4).

(37) The respective bus subscriber (S1, S2, S3, S4) transmits emergency signal 5 on both data lines (1, 2). In other words, emergency signal 5 is transmitted from the respective bus subscriber (S1, S2, S3, S4) in the direction of master module M on the second data line and is transmitted from the respective bus subscriber (S1, S2, S3, S4) away from master module M on first data line 1.

(38) The respective bus subscribers (S1, S2, S3, S4) immediately process the emergency signal 5 and at the same time forward it to the downstream bus subscriber (S1, S2, S3, S4) so that the bus subscribers (S1, S2, S3, S4) shut down immediately. In other words, emergency signal 5 is not first stored and processed but immediately forwarded to all bus subscribers (S1, S2, S3, S4) and to master module M.

(39) The emergency signal 5 may have a temporally shorter length, in particular signal length, than the data packets (3, 4) and/or transmission pause 6.

LIST OF REFERENCE CHARACTERS

(40) M master module S1 first bus subscriber S2 second bus subscriber S3 third bus subscriber S4 fourth bus subscriber 1 first data line 2 second data line 3 data packet 4 data packet 5 emergency signal 6 transmission pause