Opening a Connection
Original instructions
About us
Introduction
A connection can be opened by a request from:
With a Remote Device
The module prepares for a connection coming from a remote device.
When the connection is received, verification of the IP address of the remote machine is done if and only if access check is activated. This test consists of checking that this address is on a list of remote machines authorized to connect.
If the test is positive the connection is opened. If not the connection remains closed.
With a Local PLC
When a message is sent out by a communication function, if there is no connection with the remote device, this is opened automatically internally by the module to the remote 502 port.
Examples
Example of connections
In the example opposite, four TCP connections are open for communication between the terminal and the PLC stations or between two PLC stations.
The terminal is always able to open connections.
Either of two PLCs CANopen the connection between them (the client PLC).