Table of Contents
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Section 8
8.1 Introduction
8.2 Modbus Settings
8.2.1 N
8.2.2 Baud
8.2.3 Parity
8.2.4 Stop Bit
8.2.5 Swap Word
8.3 Modbus Function Codes
Modbus Communication
The 9186 supports bi-directional Modbus communication over the integrated
RS485 interface. This provides multi-drop, digital network capability that can be
used to connect multiple 9186 series transmitters to a Programmable Logic
Controller (PLC) or Personal Computer (PC). The 9186 is designed as a Modbus
RTU slave, which allows a Modbus RTU master to access measurements,
settings, and alarms.
The following Modbus settings are available in the RS485 menu of the 9186.
To access the RS485 menu, select MENU, PROGRAMMING, RS485, then select
the appropriate menu item as follows.
This menu item selects the Modbus slave address. Valid choices are 1–247.
The default setting is 1.
This menu item selects the baud rate used for serial communications. This setting
must match the baud rate of the Modbus master. Valid choices are 300, 600,
1200, 2400, 4800, 9600, or 19200. The default setting is 19200.
This menu item selects the parity used for serial communications. This setting
must match the parity of the Modbus master. Valid choices are No, Odd, or Even.
The default setting is No.
This menu item selects the number of stop bits used for serial communications.
This setting must match the stop bit setting of the Modbus master. Valid choices
are 1 or 2. The default setting is 1.
This menu item selects the floating point word order. Some PLC systems require
the two 16-bit registers be swapped when creating a 32-bit floating point number.
Valid choices are Yes or No. The default setting is Yes.
Four types of Modbus messages are supported by the 9186. Each message
consists of a query (request from the master) and a response. These messages
are described in
section
8.3.1.
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