Modbus master command set, Modbus data types and addressing -4, Configuration guide (aadvance controller) – Rockwell Automation AADvance Controller Configuration Guide User Manual

Page 190: Modbus data types and addressing

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Issue 07

Configuration Guide (AADvance Controller)


Modbus Master Command Set

The AADvance Modbus master supports the subset of Modbus commands listed in the

table.

Table 20:

AADvance Modbus Master Commands

Command
Code

Command

Remarks

01

Read coil status

Maximum 512 coils per message

02

Read input status

Maximum 512 inputs per message

03

Read holding registers

Maximum 125 registers per message

04

Read input registers

Maximum 125 registers per message

05

Force single coil

06

Preset single register

15

Write multiple coils

Maximum 512 coils per message

16

Write holding registers

Maximum 123 registers per message

08

Diagnostics

Subfunction 00, query used (RTU only)

Modbus Data Types and Addressing

The Modbus master supports the Modbus data types listed in the table.

Table 21:

Modbus Data Types

Data Type

Address Range

Coils

1 to 65,535

Inputs

1 to 65,535

Input registers

1 to 65,535

Holding registers

1 to 65,535


Modbus uses a numeric addressing scheme to pass data between devices. AADvance

controllers allocate a dedicated area for each of the four Modbus data types and follow
the model defined in the Modbus Application Protocol Specification.

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