Rockwell Automation 1766-L32AWA, User Manual

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Rockwell Automation Publication 1766-UM001O-EN-P - September 2021 285
Appendix G Connect to Networks via Ethernet Interface
Ethernet Connections
TCP/IP is the mechanism used to transport Ethernet messages. On top of TCP,
EtherNet/IP and/or Modbus TCP protocol is required to establish sessions and
to send the MSG commands. Connections can be initiated by either a client
program (RSLinx application) or a processor.
The client program or processor must first establish a connection to the
MicroLogix 1400 to enable the MicroLogix 1400 to receive solicited messages
from a client program or another processor.
In order to send an outgoing message, the MicroLogix 1400 must first establish
a connection with the destination node at a specified IP address on the
Ethernet network. A connection is established when a MSG instruction
executes and no previous connection exists.
When a MSG instruction executes, the MicroLogix 1400 checks to see whether
a connection has been established with the destination node. If a connection
has not been established, the MicroLogix 1400 attempts to establish a
connection of the peer type.
In order to receive messages from another device on Ethernet, an “incoming”
connection must be established. This incoming connection is made by the
sending processor and uses one incoming connection in the receiving
processor.
The MicroLogix 1400 supports a maximum of 32 EtherNet/IP connections and
32 Modbus TCP connections, allowing a maximum of 32 outgoing and a
maximum of 32 incoming simultaneous connections with up to 64 other
devices or applications. The connections are dedicated as follows:
Duplicate IP Address
Detection
The MicroLogix 1400 firmware supports duplicate IP address detection. In
Series B and Series C, duplicate IP address detection can be disabled in the
Channel 1 configuration in order to eliminate this source of broadcast traffic
for low bandwidth applications.
When you change the IP address or connect one of the MicroLogix to an
EtherNet/IP network, the MicroLogix 1400 controller checks to make sure that
the IP address assigned to this device does not match the address of any other
network device. The MicroLogix 1400 will check every 2 minutes for a duplicate
IP address on the network. If the MicroLogix 1400 determines that there is a
conflict (another device on the network with a matching IP address), the
following message gets posted on the LCD display.
Number of Connections
(1)
(1) Connections established by an INTERCHANGE™ client, RSLinx client, and peers are all included when counting the number of
connections.
Dedicated to:
16 Incoming EtherNet/IP Connections
16 (Series B and Series C only) Incoming Modbus TCP Connections
16 Outgoing EtherNet/IP Connections
16 (Series B and Series C only) OutgoingModbus TCP Connections
IMPORTANT For outgoing connections, no more that one connection per destination
node is established. If multiple MSG instructions use the same destination
node, they share the same connection.