Bronkhorst FLOW-BUS interface - Manual (Page 11)

BRONKHORST ®
2 FIELD BUS INSTALLATION
2.1 G ENERAL
FLOW‐BUS is a 3‐wire, RS485‐based field bus communication system for parameter value exchange between digital
Bronkhorst products. In this system each instrument / device is equipped with a micro‐controller for its own dedicated
task but also for exchanging parameter value information with other instruments / devices connected to the same
FLOW‐BUS system.
FLOW‐BUS systems may have a minimum of 2 and a maximum of 126 connections. The maximum length for datelines
between the first and the last connection may be up to approx. 600 meters. Longer distances are only possible in
combination with special bus‐repeater modules. Each instrument/device connection T‐part (stub) must be kept as
short as possible (maximum cable length 0.5 meter).
The baud rate used to transport messages is 187500 baud or 400000* baud.
FLOW‐BUS is a multi‐master network with a token‐ring architecture.
*MBC3 type instruments have an additional baud rate available of 400000 baud.
Page 11 FLOW‐BUS interface 9.17.024