Addressing

Previous chapterNext chapter Show allShow all    Hide allHide all

Addressing is based on the names of the variables.

Property

Description

Name

Any name may be chosen. ATTENTION: the name must be unique within every control system project. The name is also used for addressing the variable.

Identification

Any text can be entered here, e.g. for resource labels, comments ...

Can be used for addressing (optional).

Net address

Bus address or net address of the variable.

This address refers to the bus address in the connection configuration of the driver. This defines the PLC, on which the variable resides.

Data block

not used for this driver

Offset

not used for this driver

Alignment

not used for this driver

Bit number

not used for this driver

String length

Only available for String variables: Maximum number of characters that the variable can take.

Driver object type

Depending on the employed driver, an object type is selected during the creation of the variable; the type can be changed here later.

Data type

Data type of the variable, which is selected during the creation of the variable; the type can be changed here later.

ATTENTION: If you change the data type later, all other properties of the variable must be checked and adjusted, if necessary.

The naming convention is based on the following structure: SERVER!LD/LN/DATA/DataAttr[FC]

The terms are:

SERVER

the defined server name

LD

Name of the "logical device"

LN

Name of the "logical Node"

DATA

Name of the "data object", see Appendix B - Abbreviatons for data object/data attribute

DataAttr

Name of the "data attribute", see Appendix B - abbreviations for data object/data attribute

FC

"functional constraint" of the "data attribute", see Appendix A - Description of the Functional Constraints (FCs)

Example:

The logical node "XCBR1" (circuit breaker 1) has, among other things, a data object "Pos," which is a CDC (Common Data Class) "Controllable Double Point" (DPC). This data object "Pos," in turn, has attributes "stVal," "q," and "t," whose names and semantics are specified by its CDC as defined in IEC61850-7-3.

XCBR1/Pos

=

switch position

(according to LN definition XCBR in 61850-7-4)

XCBR1/Pos/stVal[ST]

=

position value

(according to CDC definition DPC in 61850-7-3)

XCBR1/Pos/q[ST]

=

Quality

(according to CDC definition DPC in 61850-7-3)

XCBR1/Pos/t[ST]

=

time stamp

(according to CDC definition DPC in 61850-7-3)

All objects in the variable model are designed this way. Therefore, the driver knows, for example, that the attributes "q" and "t" contain the quality and time stamp for the value in "stVal." This allows to access any attribute of any object in the variable model. Existing quality and time stamp values are automatically assigned to the actual value variable by the driver.
Operate Command: Thanks to the specified variable syntax, when writing to a variable, e.g. with the name "*/Oper.ctlVal[CO]" (Operation/ControlValue), the driver automatically detects that instead of a normal target value setting an operate command should be issued, so it sends the telegrams required for this to the controller.

PLC time stamping / PLC quality

Time stamp and quality attribute are always part of a variable in zenon. Variables with the attribute 'q' and 't' do not have to be created separately. The driver automatically uses the time stamp and quality of a 'data object' for all variables of an object.