Rockwell Automation AADvance Controller Configuration Guide - Manual (Page 188)

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9-2 Document: 553633
ICSTT-RM405f-EN-P
Issue 07
Configuration Guide (AADvance Controller)
Modbus Master
The AADvance controller can be used as a Modbus master to one or more Modbus
slave devices. Slave devices can include programmable logic controllers, remote devices
(typically with little or no processing capability) and, more rarely, other functional
safety controllers (Trusted or AADvance).
The controller supports the Modbus RTU and Modbus TCP protocols, and a subset
of Modbus commands. You can use Modbus RTU with point-to-point and multi-drop
serial links, and Modbus TCP with Ethernet.
Note: The AADvance controller does not support the Modbus ASCII protocol.
You can set up an individual list of messages (commands) for each slave device.
Modbus read commands cause data to read from the slave device to the Modbus
master, while Modbus write commands cause data to be copied from the Modbus
master to the slave device. You can also define a sequence of broadcast write
commands, which a Modbus master can send to multiple Modbus RTU slaves without
requiring an acknowledgement. The AADvance controller can control and monitor
individual Modbus master objects and their slave links.
The Modbus master functionality has a safety integrity level of zero (SIL0) and should
only be used for non-safety applications.
Modbus Standards
The Modbus functionality implemented by the AADvance controller meets the
following standard:
 Modbus Application Protocol Specification, version 1.1b. December 2006. The
Modbus Organisation.
Modbus Master Hardware and Physical Connections
The Modbus master functionality is built into the T9110 Processor Module; the
physical communication ports are located on the T9100 Processor Base Unit. You do
not need to add any extra hardware to the AADvance controller except to make the
physical connections to the processor base unit. The illustration shows some possible
arrangements of Modbus master connections.