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IT50SRE

5-2-55, Minamitsumori, Nishinari-ku, Osaka 557-0063 JAPAN
Phone: +81(6)6659-8201  Fax: +81(6)6659-8510  E-mail: [email protected]

EM-2379  Rev.3  P. 5 / 6

MODBUS FUNCTION CODES & SUPPORTED CODES

 

Data and Control Functions

CODE

NAME

 

01

Read Coil Status

X

Digital output from the slave (read/write)

02

Read Input Status

X

Status of digital inputs to the slave (read only)

03

Read Holding Registers

 

General purpose register within the slave (read/write)

04

Read Input Registers

X

Collected data from the field by the slave (read only)

05

Force Single Coil

X

Digital output from the slave (read/write)

06

Preset Single Registers

X

General purpose register within the slave (read/write)

07

Read Exception Status

08

Diagnostics

 

09

Program 484

10

Poll 484

11

Fetch Comm. Event Counter

 

Fetch a status word and an event counter

12

Fetch Comm. Event Log

 

A status word, an event counter, a message count and a field 
of event bytes

13

Program Controller

14

Poll Controller

15

Force Multiple Coils

X

Digital output from the slave (read/write)

16

Preset Multiple Registers

 

General purpose register within the slave (read/write)

17

Report Slave ID

 

Slave type / ‘RUN’ status

18

Program 884/M84

19

Reset Comm. Link

20

Read General Reference

21

Write General Reference

22

Mask Write 4X Register

23

Read/Write 4X Register

24

Read FIFO Queue

 

Exception Codes

CODE

NAME

 

01

Illegal Function

X

Function code is not allowable for the slave

02

Illegal Data Address

X

Address is not available within the slave

03

Illegal Data Value

X

Data is not valid for the function

04

Slave Device Failure

05

Acknowledge

06

Slave Device Busy

07

Negative Acknowledge

08

Memory Parity Error

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