Modbus/Tcp - Pepperl+Fuchs ICDM-RX/MOD Manual

ICDM-RX/MOD User Manual
Overview
The format is as follows:
Where:
• The terms Master or Client are used to identify the sender of the message.
• The terms Slave or Server are used to identify the devices responding to the message.
Modbus/ASCII is used primarily for:
• Serial port connectivity
RS-485 is the most common serial mode, but RS-232 and RS-422 are also used. Used primarily by legacy
Slave devices.
• Ethernet TCP/IP socket connections
This is not the same as Modbus/TCP, but does provide a very simple method of interfacing to remote
devices. It is used by some applications and some OPC servers.
Note: This communication method typically is not supported by PLCs.

1.3.3. Modbus/TCP

Modbus/TCP is an Ethernet network based protocol that contains a Modbus/RTU message, with the exception
of the 2-byte CRC. The Modbus/TCP message contains a header with information designed to provide
message identification and routing information. The format is as follows:
Where:
• The terms Master or Client are used to identify the sender of the message.
• The terms Slave or Server are used to identify the devices responding to the message.
• Modbus/TCP messages are typically sent to and received on a defined Ethernet TCP/IP socket of 502.
• Modbus/TCP implementations provide more capability, but also require more processing than simpler
Modbus/RTU implementations.
Modbus/TCP is used for connecting advanced Ethernet based devices, such as PLCs, HMIs, SCADA Systems,
and most OPC Servers to:
• Other Ethernet devices supporting Modbus/TCP.
• Remote serial Modbus/RTU and/or Modbus/ASCII devices through gateways (such as the ICDM-RX/MOD
running the Modbus Router or Modbus/TCP applications).
• Remote serial or Ethernet TCP/IP ASCII devices (barcode scanners, printers, RFID readers, visions
systems, etc) through a gateway (such as the ICDM-RX/MOD running the Modbus/TCP application).
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