Allen-Bradley Micro820 User Manual

48 Rockwell Automation Publication 2080-UM005B-EN-E - March 2015
Chapter 5 Communication Connections
Modbus RTU
Modbus is a half-duplex, master-slave communications protocol. The Modbus
network master reads and writes bits and registers. Modbus protocol allows a
single master to communicate with a maximum of 247 slave devices. Micro800
controllers support Modbus RTU Master and Modbus RTU Slave protocol. For
more information on configuring your Micro800 controller for Modbus
protocol, refer to the Connected Components Workbench Online Help. For
more information about the Modbus protocol, refer to the Modbus Protocol
Specifications (available from http://www.modbus.org
).
See Modbus Mapping for Micro800
on page 165 for information on Modbus
mapping. To configure the Serial port as Modbus RTU, see Configure Modbus
RTU on page 56.
Modbus/TCP Client/Server
The Modbus/TCP Client/Server communication protocol uses the same
Modbus mapping features as Modbus RTU, but instead of the Serial port, it is
supported over Ethernet. Modbus/TCP Server takes on Modbus Slave features
on Ethernet.
The Micro820 controller supports up to 16 simultaneous Modbus TCP Client
connections and 16 simultaneous Modbus TCP Server connections.
No protocol configuration is required other than configuring the Modbus
mapping table. For information on Modbus mapping, see Modbus Mapping for
Micro800 on page 165.
CIP Symbolic Client/Server
CIP Symbolic is supported by any CIP compliant interface including Ethernet
(EtherNet/IP) and Serial Port (CIP Serial). This protocol allows HMIs to easily
connect to the Micro820 controller.
CIP Serial, supported on the Micro820 controller, makes use of DF1 Full Duplex
protocol, which provides point-to-point connection between two devices.
The Micro800 controllers support the protocol through RS232 connection to
external devices, such as computers running RSLinx Classic software, PanelView
Component terminals (firmware revisions 1.70 and above), or other controllers
TIP
Use MSG_MODBUS instruction to send Modbus messages over
serial port.
TIP
Use MSG_MODBUS2 instruction to send Modbus TCP message over
Ethernet port.

Allen-Bradley Micro820 Specifications

General

Processor	32-bit
Power Supply	24V DC
Programming Software	Connected Components Workbench
Series	Micro800
Mounting	DIN Rail
Memory	Embedded
Expansion	Yes
Controller Type	Programmable Logic Controller (PLC)
Communication	Ethernet/IP
Programming Language	Ladder Diagram, Function Block Diagram, Structured Text
I/O	Embedded