Method for operating a redundant automation system
A method with which one subsystem of a redundant automation system that is provided with a first subsystem and a second subsystem is operated as a master and another subsystem is operated as a slave, where the subsystems are provided with transmission and reception tasks to transmit and receive messages, and where messages are also interchanged with program path synchronization during a temporally asynchronous run through a program path in the master and the slave.
1. A method for operating a redundant automation system provided with a first subsystem and a second subsystem which each include a processor for executing transmission and reception tasks to provide disruption free redundant operation of the automation system, comprising:
operating one of the first and second subsystems as a master and operating another of the first and second subsystems as a slave;
providing the first and second subsystems with transmission and reception tasks to transmit and receive messages;
forwarding a first message to the master using a message handler of the master such that the first message is transmitted both from a first transmission task of the master to a first reception task of the master and from a first transmission task of the slave to a first reception task of the slave, the message handler of the master being utilized to transmit a message reference to a message handler of the slave for entry in a queue of the slave, and the queue indicating a transmission sequence of messages transmitted utilizing the master;
forwarding the first message to the first reception task of the slave using the message handler of the slave after the message reference has been read from the queue of the slave utilizing the message handler of the slave to ensure processing of the messages in the master and the slave of the redundant automation system in a temporally asynchronous manner and with program path synchronization to provide disruption free operation of the redundant automation system;
wherein one of:
(i) a second message is transmitted both to the first reception task of the master and to the first reception task of the slave utilizing a second transmission task of the master by supplying the second message to the reception task of the master using the message handler of the master and a copy of the second message being transmitted to the message handler of the slave, the message copy being forwarded to the reception task of the slave utilizing the message handler of the slave when the queue does not store any message references or messages, and the copy of the second message otherwise initially being entered in the queue for forwarding to the reception task of the slave; and
(ii) the second message is transmitted both to the first reception task of the slave and to the first reception task of the master utilizing a second transmission task of the slave by one of:
(a) storing the second message using the message handler of the slave and transmitting a copy of the second message to the message handler of the master for forwarding to the reception task of the master, the message handler of the master transmitting a further message reference to the message handler of the slave, the stored message being transmitted to the reception task of the slave utilizing the message handler of the slave when the queue does not store any message references or messages, and otherwise the further message reference initially being stored in the queue, the copy of the second message being transmitted to the reception task of the slave after the further message reference has been read from the queue; and
(b) transmitting the second message to the message handler of the master utilizing the message handler of the slave for forwarding to the reception task of the master, the message handler of the master transmitting the second message to the message handler of the slave, the second message being transmitted to the reception task of the slave using the message handler of the slave when the queue does not store any message references or messages, and otherwise the second message being entered in the queue for forwarding to the reception task of the slave; and
wherein a third transmission task of one of the first and second subsystems is used to transmit a third message to a third reception task of one of the first and second subsystems by using a message handler of one of the first and second subsystems to transmit the third message to the third reception task of one of the first and second subsystems.
2. A redundant automation system, comprising:
a first subsystem operated as a master; and
a second subsystem operated as a slave, the first and second subsystems including a processor for executing transmission tasks and reception tasks to transmit and receive messages;
wherein the automation system is configured to forward a first message via a message handler to the master and transmit a message reference to a message handler of the slave for entry in a queue of the slave such that the first message is transmitted both from a first transmission task of the master to a first reception task of the master and from a first transmission task of the slave to a first reception task of the slave;
wherein the message handler of the slave forwards the first message to the reception task of the slave after the message reference has been read from the queue to ensure processing of the messages in the master and the slave of the redundant automation system in a temporally asynchronous manner and with program path synchronization in a disruption-free manner;
wherein the automation system is configured to one of:
(i) transmit a second message both to the first reception task of the master and to the first reception task of the slave utilizing a second transmission task of the master by the message handler of the master supplying the second message to the reception task of the master and transmitting a copy of the second message to the message handler of the slave, which forwards the copy of the second message to the reception task of the slave when the queue does not store any message references or messages, and otherwise enters the copy of the second message in the queue of the slave for forwarding to the reception task of the slave; and
(ii) transmit the second message both to the first reception task of the slave and to the first reception task of the master utilizing a second transmission task of the slave by one of:
(a) storing, by the message handler of the slave, the second message and transmitting a copy of the second message to the message handler of the master for forwarding to the reception task of the master, the message handler of the master transmitting a further message reference to the message handler of the slave, the message handler of the slave forwarding the stored message to the reception task of the slave when the queue does not store any message references or messages, and otherwise the further message reference initially being stored in the queue, the copy of the second message being transmitted to the reception task of the slave after the further message reference has been read from the queue; and
(b) transmitting, by the message handler of the slave, the second message to the message handler of the master for forwarding to the reception task of the master, the message handler of the master transmitting the second message to the message handler of the slave, the message handler of the slave forwarding the second message to the reception task of the slave when the queue does not store any message references or messages, and otherwise entering the second message in the queue for forwarding to the reception task of the slave; and
wherein a third transmission task of one of the first and second subsystems is used to transmit a third message to a third reception task of one of the first and second subsystems by using a message handler of one of the first and second subsystems to transmit the third message to the third reception task of one of the first and second subsystems.