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DL8 USERS
MANUAL EM-7691-B Rev.24
Modbus/TCP data is composed of the following elements (values divided by bytes converted into a hexadecimal value.)
No.
0
1
2
3
4
5
6
7
8 ...
Content
(1) Transaction ID
(2) Protocol ID
(3) Length
(4) Node ID
(5) Function code
(6) Data
setting
0
0
Total of No. 6 and
following bytes
1
Byte data
0
0
0
0
(0)
(4)
1
(1)
(0)
(4)
HEX data
00
00
00
00
(00)
(04)
01
(01)
(00)
(04)
(1) Transaction ID
The DL8 does not check the transaction identifier.
Set “00” “00” in hexadecimal.
(2) Protocol ID
The DL8 does not check the protocol identifier.
Set “00” “00” in hexadecimal.
(3) Length
Set the total data bytes of No. 6 and following bytes.
(4) Node ID
The DL8 does not check the node identifier.
Set “01” in hexadecimal.
(5) Function code
Function codes are defined specific to I/O types by Modbus protocol.
(6) Data
Data section.
The range of data returned from the slave to the Modbus/TCP master and data written by the master is as shown in the
table below.
Item
Description
AI
• When the data type is [%] (0 to 10000; voltage/current data of R8 I/O modules or remote I/O
devices):
-2000 to 12000
• When the data type is [Int] (signed integer):
Signed 16 bit integer (-32768 to 32767)
PI
• When the data type is [Accumulation] in Measurement mode:
Unsigned 32 bit integer
• When the data type is [Actual value] in Measurement mode:
Signed 32 bit integer
• When the data type is [Float] in Measurement mode:
32 bit single precision floating point
CI
Unsigned 32 bit integer
AO
Signed 16 bit integer (-32768 to 32767)
