Data Items

Table of Contents

• Accessing Data Items
• Supported Data Types

See also

Skill Data Points in the Xentara user manual

A data item maps a single variable in the target device to the Xentara model tree as a skill data point. The data item must refer to an address in the target S7 PLC and has a defined data type. In addition, it must be configured as a member of a command to be read and written.

Data items that refer to a memory area located in data blocks of the target PLC must be defined as children of the corresponding data block objects.

Accessing Data Items

See also

Accessing Xentara Elements in the Xentara user manual

S7 data items have the following attributes:

Attributes

key	The data item’s primary key.
name	The data item’s name. The name is the last component of the primary key.
UUID	The unique UUID of the data item.
type	The data item’s element type. For S7 data items, this is always “S7 data item”.
category	The data item’s category. For S7 data items, this is always “data point”.
value	The value of the data item.
quality	The quality of the current value.
error	The last read error.
writeError	The last write error. This attribute is available only if the data item is writable.
changeTime	The last time the value was changed.
writeTime	The last time the value was written. This attribute is available only if the data item is writable.

Supported Data Types

The Xentara S7 driver supports the following S7 data types:

Data Type	Description
Bool	Boolean value (true or false)
Byte	unsigned 8-bit integer
Word	unsigned 16-bit integer
DWord	unsigned 32-bit integer
LWord	unsigned 64-bit integer
SInt	signed 8-bit integer
USInt	unsigned 8-bit integer
Int	signed 16-bit integer
UInt	unsigned 16-bit integer
DInt	signed 32-bit integer
UDInt	unsigned 32-bit integer
LInt	signed 64-bit integer
ULInt	unsigned 64-bit integer
Real	32-bit IEEE 754 floating point value
LReal	64-bit IEEE 754 floating point value
String	A string of 8-Bit characters
WString	A string of 16-Bit characters