
A-90188E-01 GENERAL 2.OVERVIEW OF MODBUS/TCP FUNCTION
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2 OVERVIEW OF MODBUS/TCP
FUNCTION
FANUC MODBUS/TCP function supports Server function.
This chapter explains the outline of FANUC MODBUS/TCP Server
function.
NOTE
FANUC MODBUS/TCP function does not support
Client function.
MODBUS Data model
The following four kinds of data formats are defined as MODBUS
data model. These are called "Table".
Table name Object(Data) type Type of READ/WRITE
Discrete input Single bit READ Only
Coils Single bit READ-WRITE
Input Registers 16-bit word READ Only
Holding registers 16-bit word READ-WRITE
Only "Holding registers" can be used with FANUC MODBUS/TCP
Server function of these.
NOTE
1 "Discrete input" , "Coils" and "Input Registers" can’t
be used.
2 "READ" is the input of data from the client, and
"WRITE" is the data of output from the client.
MODBUS Function codes
FANUC MODBUS/TCP function supports the following function
codes.
Function code name Code Number
Read Holding Registers 03h
Write Multiple Registers 10h
Read/Write Multiple Registers 17h