Redundant configuration

Overview

Typically, there are two layers of redundancy with DeviceXPlorer OPC Server.

• Redundancy for DeviceXPlorer OPC Server
  In the event of a failure of the PC on which DeviceXPlorer OPC Server is running or the network, the system can continue to access data via another redundant PC on which another DeviceXPlorer OPC Server is running.
   
• Redundancy in Device Communication
  In the event of a failure of the device which DeviceXPlorer OPC Server is accessing or the network, the system can continue to access data via another redundant device.

​*Please refer to this article for information on licensing for redundant OPC server configurations.

Redundancy for DeviceXPlorer OPC Server

(Case 1)
If the host system supports redundant switching of OPC communication, please utilize the functionality within the host system to switch the OPC communication path. For example, an advanced SCADA system like ICONICS GENESIS64 supports this feature.

(Case 2)
If the host system does not support the feature, you can use a local DeviceXPlorer OPC Server for redundant switching of OPC communication. In this case, OPC client driver in local DeviceXPlorer OPC Server is used. The OPC client driver connects the remote DeviceXPlorer OPC Server and handles redundant switching. The configuration procedure in OPC client driver in the local DeviceXPlorer OPC Server is the same as the following redundant communication setting instructions with the device. The host system accesses the local DeviceXPlorer OPC Server, instead of the remote one. 
* An additional license is required for the local DeviceXPlorer OPC Server.

Redundancy in Device Communication

DeviceXPlorer OPC Server has the redundant communication function for each driver. The setting procedure is shown below.

Instructions for Setting Up Redundant Communication in the Driver

Two sets of port settings and device settings for both the primary and secondary systems are used in the redundant switching configuration.

1. Create port settings and device settings for each primary and secondary device. You only need to create tags on the primary device, and not create tags on the secondary device.
   
2. Make sure each device setting can communicate with the device without any problems.
3. Set "Redundant Communication" in the device option of the primary device setting.
   
4. By setting up redundant communication, if the host system accesses the tags of Device1 and a communication error occurs with Device1, the communication path will automatically switch to Device2. The host system does not need to access Device2 directly; it continues to access the device through Device1.
5. By monitoring the device system tag from the host system, the communication status and switching status can be checked.
   Communication Status: Device1.$Status (BOOL type)
      ON: Either communication status is good.
      OFF: Both communication statuses are down.
   Switching Status: Device1.$Standby (BOOL type)
      ON: The current communication path is through the secondary device.
      OFF: The current communication path is through the primary device.