11.2. Configuring the Cascade DataHub on Linux

OPC DataHub™ : Version 6.4
	Chapter 11. OPC to Linux

You can configure the Cascade DataHub on Linux from the command line when you start the DataHub using the datahub command. A complete list of the datahub command options is available in the Cascade DataHub for Linux and QNX manual. Here we will explain only the necessary ones.

Configure the Cascade DataHub as mirroring slave

If the OPC DataHub on the Windows machine has been configured as a tunnelling master, the Cascade DataHub on the Linux machine must be configured as a mirroring slave.

Start the DataHub using this command-line syntax:
```
[sh]$ datahub -M address -m port -n domain
```
where:
address
The name or IP address of the Windows computer.
port
The TCP port number used by the DataHub for mirroring. The DataHub's preconfigured default is 4600.
domain
The name of the data domain on the OPC DataHub where the OPC data is coming from.
Once you enter this command, the Cascade DataHub will start on the Linux machine and attempt to connect to the OPC DataHub on the Windows machine.
To see the data, start xdhview like this:
```
[sh]$ xdhview -d domain &
```
where domain is the same as you entered for the DataHub. When you enter this command, the X Windows version of a DataHub viewer should open, allowing you to see the incoming OPC data.

Configure the Cascade DataHub as mirroring master

If the OPC DataHub on the Windows machine has been configured as a tunnelling slave, the Cascade DataHub on the Linux machine must be configured as a mirroring master.

Start the DataHub like this:
```
[sh]$ datahub -d domain -p 4600
```
where domain is the same name you entered on the Windows machine as the Remote data domain.
Once you enter this command, the Cascade DataHub will start on the Linux machine and should accept any attempt by the OPC DataHub on the Windows machine to make a connection.
To see the data, start xdhview like this:
```
[sh]$ xdhview -d domain &
```
where domain is the same as you entered for the DataHub. When you enter this command, the X Windows version of a DataHub viewer should open, allowing you to see the incoming OPC data.

Please refer to the Cascade DataHub for Linux and QNX manual for more information about using the Cascade DataHub in Linux.