Method for integrating a further bus subscriber into a bus system, and bus system for integrating a further bus subscriber therein

Abstract

A method for integrating a further bus subscriber into a bus system, and a bus system, having a master module and subscribers disposed in series, includes the temporally consecutive method steps: in a first method step, the further bus subscriber transmits a data packet to the master module in order to log in to the master module, in a second method step, a bus subscriber disposed between the further bus subscriber and the master module stops the data packet and checks whether the bus system has already received a release, in a third method step, the first bus subscriber forwards the data packet to the master module if the bus system has not yet received a release, or in a third, in particular an alternative, method step, if the bus system has already received a release, the bus subscriber stores the data packet and waits until the release of the bus system is revoked and after the release has been revoked, forwards the stored data packet to the master module.

Claims

1. A method for operating a bus system that includes a master module and bus subscribers arranged in series and downstream of the master module, comprising: initializing the bus system, including: sending, by the master module, a request to the bus subscribers to log into the master module; each active bus subscriber, in series order, logging into the master module after receiving the request, forwarding the request to an immediately-adjacent downstream bus subscriber, and waiting for a predetermined time period for the immediate-adjacent downstream bus subscriber to log into the master module; and stopping the initializing after the predetermined time period has elapsed without a bus subscriber logging into the master module and closing the bus system to a further bus subscriber; after closing the bus system, sending a data packet by the further bus subscriber to the master module; while the bus system is closed, stopping the data packet by a bus subscriber that is logged into the master module and is located upstream from the further bus subscriber; after the bus system is no longer closed, forwarding the stopped data packet to the master module, admitting the further bus subscriber to the bus system, and closing the bus system after the predetermined time period has elapsed without an additional bus subscriber logging into the master module.

2. The method according to claim 1, wherein the initializing includes automatically assigning, by the master module, a bus address to each logged-in bus subscriber.

3. The method according to claim 1, wherein the initializing includes assigning a bus address to each bus subscriber, each bus subscriber incrementing its assigned bus address and forwards the incremented bus address to a downstream bus subscriber to assign the incremented bus address to the downstream bus subscriber.

4. The method according to claim 1, wherein the initializing is aborted if a number of bus subscribers connected to the bus system exceeds a maximally allowed number of bus subscribers.

5. The method according to claim 1, wherein the master module aborts the initializing if the master module determines that a number of bus subscribers connected to the bus system exceeds a maximally allowed number of bus subscribers.

6. The method according to claim 1, wherein the bus subscribers and master module communicate with each other via a first data line and a second data line.

7. The method according to claim 1, further comprising closing the bus system by a control device superordinate to the master module.

8. The method according to claim 1, further comprising revoking closure of the bus system by a control device superordinate to the master module.

9. The method according to claim 1, wherein the bus subscribers include drives, electronic components, and/or drive converters for electric motors of an industrial plant.

10. The method according to claim 1, further comprising forwarding, without interruption and without a time delay, a data packet through an inactive bus subscriber.

11. The method according to claim 1, further comprising shutting down all bus subscribers in response to detection of an error by the master module and/or a bus subscriber.

12. A bus system, comprising: a master module and bus subscribers arranged in series and connected to each other via at least one data line; wherein the bus system is adapted to perform the method recited in claim 1.

13. The method according to claim 6, wherein the master module transmits data packets to the bus subscribers via the first data line.

14. The method according to claim 6, wherein the master module receives data packets from the bus subscribers via the second data line.

15. The method according to claim 6, wherein at least one of the data lines includes at least one data cable.

16. The method according to claim 6, wherein the master module and each bus subscriber includes a first connector connected to the first data line and a second connector connected to the second data line.

17. The method according to claim 7, further comprising revoking closure of the bus system by a control device superordinate to the master module.

18. The method according to claim 16, wherein the each data line includes a first connector plug part plug-connecting to a second connector plug part of the first connector.

19. The method according to claim 11, wherein the shutting down includes interrupting a currently-transmitted data packet and transmitting an emergency signal.

20. The method according to claim 13, wherein the master module receives data packets from the bus subscribers via the second data line.

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 on a data bus.

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

(4) FIG. 4 shows the time characteristic of data packets 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 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 in the direction of the series arrangement than the other bus subscriber (S1, S2, S3, S4). 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 which 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 may be arranged as a plug connector part 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 also be disposed in this cable sheath.

(13) Each bus subscriber (S1, S2, S3, S4) has a switch, in particular as a component of 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 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 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 the bus subscribers (S1, S2, S3, S4) situated downstream to log in to master module M. An active bus subscriber (S1, S2, S3, S4) 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) disposed 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 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 into 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 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 operation of the bus system begins.

(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 to master module M. If a release was already granted, this data packet is stopped by an upstream bus subscriber (S1, S2, S3, S4) that is logged in to master module M and will not be forwarded to master module M.

(26) As soon as the release has been revoked, a data packet 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 start-up 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 automatically assigned. 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 the bus subscriber (S1, S2, S3, S4) disposed downstream. 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) that is given 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 is 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 by 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 is 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 than the data packets (3, 4) and/or transmission pause 6.

LIST OF REFERENCE CHARACTER

(40) M master module

(41) S1 first bus subscriber

(42) S2 second bus subscriber

(43) S3 third bus subscriber

(44) S4 fourth bus subscriber

(45) 1 first data line

(46) 2 second data line

(47) 3 data packet

(48) 4 data packet

(49) 5 emergency signal

(50) 6 transmission pause