Fnc 276 - Modbus Read/Write Instruction; Outline; Explanation Of Function And Operation - Mitsubishi FX3U Series User Manual

FX Series Programmable Controllers
3U
User's Manual - MODBUS Serial Communication Edition
8.2

FNC 276 - MODBUS Read/Write Instruction

8.2.1

Outline

This instruction allows the MODBUS Master to communicate (read/write data) with its associated Slaves.
1) Instruction Format
FNC 276
16-bit Instruction
ADPRW
2) Set Data
Operand Type
Slave Node Address
S
Command Code
S
1
Command Parameter depending on the Command Code (See Section 8.3)
S
2
Command Parameter depending on the Command Code (See Section 8.3)
S
3
Command Parameter depending on the Command Code (See Section 8.3)
S / D
4
3) Applicable Devices
Bit Devices
Operand Type System User
X Y M T C S D .b KnX KnY KnM KnS T C D R U \G
S
S
1
S
2
S
3
/
S D
4
8.2.2

Explanation of function and operation

1) 16-bit operation (ADPRW)
Command Code
and /
S4
Use 0 as the Slave Node Address for Broadcast commands.
Command
input
(normally ON)
FNC276
ADPRW
Mnemonic Operation Condition
11 steps ADPRW
Description
Digit Specification
is operated on Slave Node
S
1
.
D
Slave
Node Command
Address code
S S1
8.2 FNC 276 - MODBUS Read/Write Instruction
32-bit Instruction
Continuous
Operation
Word Devices
Special
System User
Unit
V Z Modify K H
according to Parameters
S
Command Code
Parameters
S2 S3 S4
8 Master Specification
Mnemonic Operation Condition
Data Type
16-bit binary
16-bit binary
16-bit binary
16-bit binary
Bit or 16-bit binary
Others
Con- Real Charac-
Index
stant Number ter String
E " "
, ,
S S
2 3
/ D
Command Parameters
depending on the
Command Code
(See Section 8.3)
Command Code
(See Section 8.3)
Slave Node Address
00H to 10H (0 to 16)
1
2
3
4
5
Pointer
6
P
7
8
9
10
79