EtherSBus

Ether-S-Bus (sbus)

Ether-S-Bus is a protocol used for communication with and between PCDs (Process Control Devices), which are PLCs (Programmable Logic Controllers) manufactured by Saia-Burgess Controls Ltd. The protocol contains all necessary functions to completely configure, program a PCD, and visualize its memory content and the states of the I/Os.

History

The first S-Bus (Saia Bus) was developed together with the first PCD type in 1990. At this time only the Serial-S-Bus on R S485 and R S232 was implemented. Due to the constant evolution of the controllers, additional communication interfaces such as USB, Ethernet (Ether-S-Bus), and FDL (Fieldbus Data Link, used with Profi-S-Bus) were added. Ether-S-Bus is the implementation of S-Bus on Ethernet. This step was done in order to increase the communication speed and also add multi-master capability. Further on, other Ethernet-based protocols such as HTTP, FTP, and SMTP, which were implemented to the new controllers, can now run on the same physical port of the controller.

Protocol dependencies

Ether-S-Bus uses UDP as its transport protocol. The port used by Ether-S-Bus is 5050.

Example traffic

EtherSBusScreenShot.png

Wireshark

The sbus dissector for Ether-S-Bus is fully functional (also it doesn't dissect every special command in detail). The plugin for Ethereal 0.99.0 (for Windows) is available at http://www.sbc-support.ch/faq.

Preference Settings

There are no preference settings for the sbus dissector.

Example capture file

Display Filter

A complete list of PROTO display filter fields can be found in the display filter reference

Show only the Ether-S-Bus based traffic:

 sbus

Capture Filter

You cannot directly filter Ether-S-Bus protocols while capturing. However, you can filter on UDP port 5050.

Capture only the Ether-S-Bus traffic over the default port (5050):

 udp port 5050

Discussion