Definition: Group

Group definitions are used to control data exchange: process variables from different communication channels can be assigned to a group. The group definition contains the information in which cycle or for which event the process variable values are exchanged between the variable server and the communication component.

For the data exchange to work at all, each process variable must exist in a group. Therefore, all new process variables added to a project are automatically entered in the "Standard" group.

Groups provide the following functionalities:

Synchronous or asynchronous data exchange can be set individually for read and write accesses
Process variable value-controlled activation of the data exchange of all process variables via a control variable

Parameter name	Description of the
Sampling time	Cycle time of the data exchange
Definition active	Determines whether the object definition is valid.
Activation mode	Data exchange automatically or controlled by variable value
Hysteresis	Degree of change of process variable values at which a read access is triggered.
Comment	Optional commentary on the object.
Read access	Synchronous or asynchronous data exchange for read access.
Name	Name of the object.
Write accesses	Synchronous or asynchronous data exchange for write accesses
Trigger variable	Process variable for controlling the reading and writing of a group
Time zone difference	Correction of the process variable timestamp when a time zone limit is exceeded