Effective October 2012
Supersedes August 2006
Instructional Leaflet IL01412009E
Pow-R-Command™ 1000—
breaker control bus communication protocol
Introduction
Eaton’s Breaker Control Bus (BCB) communicates
using a sub-set of the Modbus
®
protocol.
This protocol is intended to provide a simple
mechanism for systems integrators and OEM
applications to communicate with Eaton
rail drivers. Consult the Modbus protocol
specification (http://www.modbus.org) for
more detailed information on the protocol.
The rail drivers communicate over a multi-drop
twisted pair RS-485 network using RTU formatted
messages at 9600 baud, no parity, 8 data bits,
and 1 stop bit. The maximum packet size including
addressing and CRC is 80 bytes.
Up to 16 Eaton BCBs can be connected to a single
network. Each BCB must have a unique address
from 1 to 16. The address is set with DIP switches
on the BCB itself.
Table 1
shows the DIP switch
settings for each address.
Table 1. Device/Settings
Device Address
DIP Switch Settings
1
00000001
2
00000010
3
00000011
4
00000100
5
00000101
6
00000110
7
00000111
8
00001000
9
00001001
10
00001010
11
00001011
12
00001100
13
00001101
14
00001110
15
00001111
16
00010000
Up to 21 EATON BABRSP or GHQRSP-series
remotely operated circuit breakers can be
connected to each BCB. Each breaker is
referenced through a Modbus output coil
register. The first breaker is located nearest
the controller as indicated on
Figure 1
.
Breaker control bus
Breaker 2 (Coil 1)
Breaker 1 (Coil 0)
Breaker 21 (Coil 20)
Figure 1. Modbus Output Coil Register
The following Modbus commands are processed
by the Eaton BCB.
Table 2. Modbus Commands
Command
Definition
Function
2 (0 x 02 hex)
Read 1X Registers Read breaker feedback
status, presence, last
command, and alarm
5 (0 x 05 hex)
Write Single Coil Force breaker on/off
17 (0 x 11 hex) Report Slave ID
Read rail driver information
65 (0 x 41 hex) Device-Specific
Eaton-specific commands
(e.g., Device Reset)
The Eaton BCB rails must be powered from
29 Vac control transformer rated at 96 VA. Consult
the BCB Installation Manual for more information.
