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EtherNet/IP
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6.4
Explicit Messaging
Explicit Messaging is used in commissioning and parameterizing of the EtherNet/IP.
The explicit messages provide multipurpose, point-to-point communication paths between two
devices. They provide the typical request/response-oriented network communication used to
perform node configuration and problem diagnosis. The explicit messages typically use low priority
identifiers and contain the specific meaning of the message right in the data field. This includes the
service to be performed and the specific object attribute address.
NOTE!
If Class 1 connection (cyclic data) has been established, the Explicit Messages should not be
used to control the Output Data. However this restriction does not apply for the IO Data reading.
6.4.1
List of data types
The elementary data types in CIP are (among others):
* ISO/IEC-8859-1 encoding.
Table 7. EtherNet/IP datatypes
Name
Description
Bit size
Range
Minimum
Maximum
BOOL
Boolean
8
0 = FALSE
1 = TRUE
SINT
Short Integer
8
-128
127
INT
Integer
16
-32768
32767
DINT
Double Integer
32
-2
31
2
31
- 1
LINT
Long Integer
64
-2
63
2
63
- 1
USINT
Unsigned Short Integer
8
0
255
UINT
Unsigned Integer
16
0
65535
UDINT
Unsigned Double Integer
32
0
2
32
- 1
ULINT
Unsigned Long Integer
64
0
2
64
- 1
REAL
Floating Point
32
See IEEE 754
LREAL
Long Floating Point
64
See IEEE 754
STRING *
Character string (1 octet
per char.)
N
SHORT_STRING *
Character string (1 octet
per char., 1 octet length
indicator)
N+1
BYTE
Bit string (8 bits)
8
WORD
Bit string (16 bits)
16
DWORD
Bit string (32 bits)
32
LWORD
Bit string (64 bits)
64
