Perle Systems Technical Notes
IP-Encapsulation of Automation Protocols
IP-Encapsulation is the tunneling of serial data into network packets and the transport of the data over a network. Typical applications for Serial Tunneling are remote configuration, programming, monitoring and management of industrial devices. Where PC's have been traditionally used, Perle's TruePort COM port re-director can provide the encapsulation
An example of encapsulation with a COM port redirector is with a Siemens Micro/WIN software application that normally communicates over a direct RS232 link. By installing TruePort on the Windows workstation, serial data directed to the serial COM port is redirected and IP-encapsulated for transmission over ethernet. Local to the PLC, a serial to ethernet device server then converts the packets to serial enabling remote communication between the serial-based Micro/WIN application and the PLC.
Other applications provide the conversion to IP. Kepware as example can IP-encapsulate Allen Bradley DF1 over ethernet. A serial to ethernet device server such as the IOLAN DG then does the final conversion to serial for connection to the PLC.
Serial Device Servers can also be used to run IP-encapsulation in “back to back” mode. This may be required when there is no ethernet capability in the target devices such as older PLC’s