Create a new pipe

Allows you to build new pipes. A pipe receives values from OPC items on one OPC server and sends those values to items on another OPC server. Pipes can be either one-way or two-way.

Start Mirror Configuration by selecting Start → Programs → OPC Mirror → OPC Mirror Configuration.
Click Pipe → New Pipe to open the New Pipe dialog.
Type a name in the Pipe Name box.
Select hosts and servers for the new pipe.
Note
These can be changed later.
Fill in or select from the options in the dialog:
- Enabled checkbox
- Update Rate
- Deadband (%)
- Pipe Direction
- Initial Data Node (for two-way pipe)
- Description
- Automatic Refresh
Note
These options can be changed later.
Click Create when all options and parameters are set.

Using one-way pipes

For a one-way pipe, only the value from the source will be written to the destination. If you change the value in the destination, it will not be reflected at the source. However, if you have Automatic Refresh turned on, the value will be refreshed. Therefore, if you want to keep the changed value, turn Automatic Refresh off.

Using two-way pipes

The use of bidirectional pipes with OPC Mirror is designed to accommodate data such as user-input values, where two operators can set the value from either end. Bidirectional pipes are not generally useful for communicating live process data (especially data that changes frequently) or where one end of the pipe should always be considered the source.

For a two-way pipe, if a value is changed at one server, OPC Mirror will write it to the server at the other end of the pipe. This will automatically generate an update message from the server that was just written to back to OPC Mirror. Under the following conditions, OPC Mirror will not pass the same value back to the original server at the source end of the pipe:

If the original server at the source end of the pipe is specified as the initial data node, making it the master end.
If the original server at the source end of the pipe is the slave end and new values are not coming from the slave end faster then they can be written to and reflected from the master end. Depending on location of master end node, the reflection may take several seconds, or more.

Important

If a value is changed simultaneously at both servers on each end of a bidirectional pipe, a race condition can occur that may cause the final value on both servers to be undetermined. Depending on the nature of the race condition, multiple messages may bounce back and forth before a single value is finalized for both servers.

Note

OPC Mirror supports reading data values from SIS modules, but does not support writing to SIS modules protected by its Secure Writes Mechanism.