Perle Systems Technical Note

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 Windows® , Linux, Solaris, Unix based Personal Computers (PCs) are used, an Ethernet adapter and  Perle’s com port redirector called TruePort may be used in place of a Device Server.

An example of encapsulation with a com port redirector is the 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 converters the packets to serial enabling remote communication between the serial-based Micro/WIN application and the PLC.

Other applications provide the convertion to IP. Kepware as example can IP-encapsulate Allen Bradley DF1 over ethernet. A serial to ethernet device server such as the IOLAN DS1 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