Kipp & Zonen RaZON+, Instruction Manual

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MODBUS TCP Slave Application Protocol
Introduction
This section describes the MODBUS TCP slave application protocol of the RaZON
+
. The protocol is a subset of the MODBUS RTU slave
application protocol. The differences are highlighted.
Supported commands
The MODBUS TCP slave application protocol supports the following MODBUS function codes:
(0x01) Read Coils
(0x02) Read Discrete Inputs
(0x03) Read Holding Registers
(0x04) Read Input Registers
Communication parameters
The default communication parameters are:
TCP port 502
Number of connections 10
Slave ID 1
When the server has 10 socket connections and receives a new connection request it will accept the new connection and drop the
oldest connection. The oldest connection is determined on base of the ‘alive’ time. The ‘alive’ time is initially set to the connection
accept time and is updated upon each request. The HOST application must be able to handle disconnection or shutdown of the
connection by the server.
The used Input/holding registers and Discrete inputs/coils are identical with the serial MODBUS RTU slave application protocol.