Addressing

The data points are addressed via a COA (common object address), an IOA (information object address) and the IEC870 Type. The type defines the function of the variable (see interoperability list). The COA corresponds to the sector of the device in which the variable resides. The IOA determines the offset in that sector.

Settings for the unique addressing of variables

Property	Description
Name	Any name may be chosen. ATTENTION: the name must be unique within every control system project.
Identification	Any text can be entered here, e.g. for resource labels, comments ...
Net address	Bus address or net address of the variable. This address is used to define the allocation to the device specified in the driver configuration. The Net address used there must be entered in the variable configuration.
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.
IEC870 type	Defines the type and function of the variable according to the IEC870 specification.
IEC870 COA1	Corresponds to the sector of the device in which the variable resides.
IEC870 IOA1	Address of the variable within a sector

The current connection status can be requested via a USINT variable of type "internal state" (T00). If the value of this variable is 5, this means that a connection is active and that the general request was finished successfully.

The communication is spontaneous, This means that all value changes of the PLC are processed by the driver.

Example:
The PLC sends three value changes at intervals of 5 ms, which are passed on to zenon. If the changes occur within the update time, in which the driver cyclically reads telegrams, the single telegram contains all value changes.
E.g. if you use a reaction matrix that reacts to every value change and triggers a log entry in the Chronological Event List (CEL), the CEL will contain three entries at intervals of 5 ms. The same applies to spontaneous archiving and alarms. None of the values are lost.