Chapter 8 Logic Instructions
8-193
Parameter name Function Data type
Validation timing
where data received are
%QW0~%QW63
FALSE to TRUE
Read_Buffer_Address
_Offset
starting register of the
master receiving data.
The setting value 1
means the offset is 1 word
if the word register of the
slave is read.
The setting value 1
means the offset is 1 bit if
the bit register of the
USINT
0~255
(0)
When Execute
changes from
FALSE to TRUE
Read_Destination_Ad
dress
address of the MODBUS
slave that the master is to
UINT
16#0~16#FFFF
(0)
When Execute
changes from
FALSE to TRUE
Read_Length
The length of data to be
read
UINT
ObjType: 0;
0~256 for
ObjType: 1;
(0)
When Execute
changes from
FALSE to TRUE
Read_FunCode
used for reading the bit
USINT
1~2
(0)
changes from
Timeout
master to wait for the
slave’s response. The
slave timeout occurs if the
slave does not respond to
the master request within
UINT
0~65535
(0)
When Execute
changes from
FALSE to TRUE
Note:
1. The input parameters SlaveIP_segment1, SlaveIP_segment2, SlaveIP_segment3 and
SlaveIP_segment4 are respectively segment 1~ segment 4 of the IP address of the slave. E.g. the slave
IP is 192.168.1.10. So the input value of SlaveIP_segment1 is 192, SlaveIP_segment2 is 168;
SlaveIP_segment3 is 1 and SlaveIP_segment4 is 10.
2. The input parameters Write_Buffer_Address and Read_Buffer_Address mean the starting registers of the
MODBUS TCP master where sent and received data are stored. The two input values must be entered.
You can define variables and combine register addresses such as %MW0 for them.
3. The input parameter ObjType is the data type of the read/written parameter. If ObjType is 0, that means
to read and write the word registers of the slave and the range of Write_Length and Read_Length is
0~100. Write_Length and Read_Length can not be 0 simultaneously.
If ObjType is 1, that means to read and write the bit registers of the slave and the range of Write_Length
and Read_Length is 0~256. Write_Length and Read_Length can not be 0 simultaneously.