YASKAWA VIPA System SLIO Manual page 188

Deployment OPC UA
Basics OPC UA > OPC UA data types and their conversion
Data type mapping
Siemens S7 data type
BOOL
BYTE
WORD
DWORD
INT
DINT
REAL
S5TIME
TIME
DATE
TIME_OF_DAY (TOD)
CHAR
COUNTER
TIMER
STRING
DT
188
SPEED7 PLC OPC UA data type
BOOL
BYTE
WORD
DWORD
INT
DINT
REAL
S5TIME
à
TIME
DATE
TIME_OF_DAY
CHAR
COUNTER
TIMER
STRING
DT
Particularities
n String
– The data type STRING in Siemens S7 is a byte array in which the maximum
length and the current length are stored in the first 2 bytes. The other bytes store
the string.
– The OPC UA data type String should be defined in the same way.
n Array
– A read or write job in OPC UA is always an Array access, i.e. always provided
with index and length.
– A single variable is a special case of an Arrays (index 0 and length 1). On the line,
the data type is simply sent several times in succession. For the variable, the
DataType attribute points to the base data type. The ValueRank and ArrayDimen-
sions attributes determine if it is an array and how large the array is.
n Structure
– A structure describes a complex data type.
– You can describe your own structures as a subtype of the abstract data type
Structures, which inherits from the data type BaseDataType.
– Since a client may not know user-specific structures, the variables of the data
type of this structure are uniformly published in an ExtensionObject. The structure
ExtensionObject can be read by any client and also publishes the DataTypeId of
the user-specific structure.
– All structures that are not described by structures of the basic data types are pub-
lished on the server in a TypeDictionary.
– With the description of the structure by the TypeDictionary and the DataTypeId,
which is published by the ExtensionObject, the structure of the ExtensionObject
can be decoded by a client.
– If a client knows in advance the description of a user-specific structure, it can be
decoded without reading the TypeDictionary. In this approach, a client needs to
read and decode the entire tree to access individual elements.
VIPA System SLIO
OPC UA built-in data type
Boolean
Byte
UInt16
UInt32
Int16
Int32
Float
UInt16
à
Int32
UInt16
UInt32
Byte
UInt16 (Only valid values)
UInt16 (Only valid values)
String
Byte[8]
HB300 | CPU | 013-CCF0R00 | en | 19-30