Tab: Redundancy Settings – General

The tab includes the configuration of the watchdog, the task with the desired services, and the fieldbus for redundancy.

Table 8. Application

Redundancy task name

Name of the task that is synchronized between both devices

Only this one task is synchronized.

Example: MainTask

Note

The task name is also entered in the RTS configuration file when you click the Write button. Alternatively, you could also manually edit the file.

Timeout (ms)

Time span to wait for the response from the active PLC

After that, the standby PLC switches to standalone mode. In this case, the task execution is delayed by this time span.

Example: 50

Recommendation: Set the value higher than the maximum task jitter time plus the maximum transmission time for redundancy messages.

Note

The setting is also stored in the RTS configuration file (StandbyWaitTime).

Note

When you deploy the CIFX-DP adapter, set the timeout to 100 ms in order to remain in sync in case of a reset.

Synchronization timeout (ms)

Time span to wait during a synchronization.

After this period of time, the standby PLC switches to standalone mode.

You can set the value optimally if you first determine the required synchronization time after getting a system trace from the PLC. See the Record the needed sync time in system trace option below.

Example: 100

If the synchronization takes longer than the timeout is allowed in Timeout (ms), and the jitter of PLC 1 is acceptable, then you can use this setting. Then the time span until the response has to be received is extended by this value.

Tip

Increase this setting in step-by-step when you encounter these kinds of synchronization problems.

The logger message Synchronization terminated after x ms because of SyncWaitTime refers to this situation.

Note

A redundant system switches to the synchronization phase for the start of the redundant PLC, a download, an online change, and the synchronization by means of user commands. During the synchronization phase, the task cycle time of the active PLC can be longer.

Table 9. Runtime Settings

Setting the `CmpRedundancy` runtime system component Tip When you click the Write button, the values set here in the development system are transferred to the runtime system.
Auto sync	: Synchronization of the data on the 2nd PLC when the connection is restored after a connection failure
Data sync always	: Synchronization of data one time at initialization and in each task cycle after that
Debug messages	: Output of additional messages in the logger file
Record the needed sync time in system trace	: A system trace is generated in the runtime system, which can be loaded into the CODESYS project. You can use the system trace to determine the value currently required for synchronization and therefore optimise the value for the Synchronization timeout (ms). For instructions, see : Synchronizing Redundant Data This option, which can be enabled here in the dialog, is entered in `CODESYSControl.cfg` under the `[CmpRedundancy]` section as the setting `EnableSyncTimeTrace`. The default value is 0.

Table 10. Fieldbus Settings

EtherCAT

standard icon : EtherCAT is used as the fieldbus.

Source address (MAC) PLC1: Corresponds to the EtherCAT master address
Source address (MAC) PLC2: Different from the address above and corresponds to the adapter on PLC 2 which is used for EtherCAT

Note

The NIC settings for the adapter have to be set on both PLCs. You need to verify this. You can use the Browse button to automatically search for the respective PLC.

Profibus

standard icon : Profibus is used as the fieldbus.

Read	Reads into the dialog the current settings of the redundancy link for PLC 1
Write	Transfers the available settings of the redundancy link on both devices