Get the most out of the zenon redundancy
With zenon version 3.51, released in 1996 COPA-DATA introduced the first version of the highly sophisticated seamless zenon redundancy. This feature is implicitly available with each zenon installation and does not require any additional licensing. For almost 20 years the zenon redundancy has been configurable via an ergonomic one-click configuration and is used in thousands of applications. With zenon version 7.11 COPA-DATA enhanced the zenon network with two additional redundancy concepts to provide more flexibility in designing the zenon network.
Redundancy mode DOMINANT
If DOMINANT mode is selected, the well-known network behavior is in operation. This means, a dedicated PC is defined for the role of server and standby. As long as the server PC is available, this PC will be in the server role. If the server PC fails, the PC defined as standby will jump into the server role. The second PC will go into standby again if the PC defined as server is back on duty.
Redundancy mode NON DOMINANT
In NON DOMINANT mode PC1 and PC2 are equal in terms of the server role. In this network constellation it doesn’t matter which PC is currently in the server or standby role. The PC which was started first will run in the server role, the second PC as standby. If the server PC fails, the standby PC will take over the server role. This PC will also continue as server even if the former server becomes active again. The reestablished PC will jump into the standby role. Due to this behavior there is no need to do a redundancy switch after a reconnection of the standby PC. If there is no dedicated requirement for a DOMINANT or RATED network environment, COPA-DATA suggest using the NON DOMINANT mode for your projects.
Redundancy mode RATED
On top of the above described network modes there is the redundancy mode RATED. In this mode an evaluation based on process variables will decide, which PC should be the active or standby server. In the editor a rating-matrix can be defined; this matrix is used to evaluate the best suitable network constellation during runtime. For example, if the primary server loses a connection to a PLC due to a network failure but the current standby is able to communicate to this PLC, a redundancy switch will be performed in order to keep as many datapoints connected to the field as possible.
With the enhancement of the redundancy functionality zenon provides most flexibility in designing the network topology according to specific requirements of each single project.