Modbus SIO Slave
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Device

Bit Address

Word Address

32 bits

Remarks

Coil

000001-065536

000001-065521

or

 

*1 

Discrete Input

100001-165536

100001-165521

*2 

Input Register

300001,00-365536.15

300001-365536

*2

Holding Register

400001,00-465536,15

400001-465536

*1You can set the data storing order in 32-bit data word units and 64-bit data double-word units in the Device Setting dialog box.

*2Write disable

 

IEC61131 Syntax Address Description

The following is a corresponding table for IEC61131 syntax and MODBUS syntax address descriptions.

Device

MODBUS Syntax

IEC61131 Syntax

Format

0-based

1-based

Format

Range

First element

Range

First element

Range

First element

Coil

000001+i

i = 0 to 65535

000001

%Mi

i = 0 to 65535

%M00000

i = 1 to 65536

%M00001

Discrete Input

100001+i

i = 0 to 65535

100001

-

-

-

-

-

Input Register (Word)

300001+i

i = 0 to 65535

300001

-

-

-

-

-

Input Register (Word bit)

300001+i, j

i = 0 to 65535

j = 0 to 15

300001,00

-

-

-

-

-

Holding Register (Word)

400001+i

i = 0 to 65535

400001

%MWi

i = 0 to 65535

%MW00000

i = 1 to 65536

%MW00001

Holding Register (Word bit)

400001+i, j

i = 0 to 65535

j = 0 to 15

400001,00

%MWi:Xj

i = 0 to 65535

j = 0 to 15

%MW00000:X00

i = 1 to 65536

j = 0 to 15

%MW00001:X00

Holding Register (Double word)

400001+i

i = 0 to 65535

400001

%MDi

i = 0 to 65535

%MD00000

i = 1 to 65536

%MD00001

Holding Register (Float)

400001+i

i = 0 to 65535

400001

%MFi

i = 0 to 65535

%MF00000

i = 1 to 65536

%MF00001

Holding Register (String)

400001+i

i = 0 to k*1

400001

%MWi

i = 0 to k

%MW00000

i = 1 to k

%MW00001

*1k is equal to 65535 - string length / 2 rounded to the upper value. For instance with a 11 characters string we’ve got 65535 - 6 = 65529.

 

NOTE

Supported Devices Symbol and Terms

IEC61131 Syntax Address Mapping

Address mapping in BLUE is as follows. %MD and %MF use two sequential words form the specified address.