Modbus/Rtu And Modbus/Ascii To-Slaves Interface; Communication Methodology - Pepperl+Fuchs ICDM-RX/MOD Manual

ICDM-RX/MOD User Manual
Overview

1.6. Modbus/RTU and Modbus/ASCII To-Slaves Interface

The ICDM-RX/MOD provides access to serial Modbus/RTU and Modbus/ASCII slave devices. Modbus master
messages are translated to appropriate Modbus slave messages, public slave devices are automatically
located, and appropriate responses are returned to the Modbus master.

1.6.1. Communication Methodology

The ICDM-RX/MOD translates various Modbus formats and forwards them to public slave devices attached to
the Modbus To-Slaves configured serial ports. Each Modbus message is transmitted and a response is
expected. The ICDM-RX/MOD times out the Modbus messages if there is no response returned within the
configured timeout period.
The following diagram displays the Modbus message transfer. The following apply to Modbus To-slaves serial
ports.
• All valid Modbus messages are translated to the appropriate format for serial port or Modbus/TCP
transmission.
• Local public Modbus slave devices are automatically located on a ICDM-RX/MOD 2-port or 4- port.
• Local and remote public Modbus slave devices can be accessed from a Modbus master as if they were of
that master's protocol type.
• Messages are timed out if no response is returned within the configured timeout period.
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Modbus Master(s) to Public Modbus Slave(s)