Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 119)

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Concepts and Base Components
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DMS 4.1 EN 03/2011 TD29 117
3.11.6 Network Variables
If supported by the device (target system), data exchange within a network is possible
via Network Variables.
Network Variables must be defined in fix variables lists as well in the sender as in the
receiver devices (handled in one or in different projects) and their values will be
transmitted via broadcasting. Regard that this is basically different from exchanging
data via a Data Server, which uses defined point-to-point connections between the
local application and remote data source(s).
Network Variables are handled in
• Global Variable Lists (GVL) in a sending device (Sender) and in a corresponding
• Global Network Variables List (GNVL) in a receiving device (Receiver). GNVLs are
viewed in the Network Variables List Editor.
• The corresponding GVL and GNVL must contain the same variable declarations.
• A Global Variable List (GVL) which should define the Network Variables of a sender,
must have special network properties. These are protocol and sending parameters,
according to which the variables values will be broadcasted within the network
and can be received by all devices which have a corresponding GNVL.
• Regard that the direction of transmission is always one-way, from GVL (sender) to
GNVL (receiver) ! However each device can define GVLs as well as GNVLs and thus
also can act as a sender AND a receiver. A sender GVL can be provided within the
same or by another project. So, when creating a GNVL, the sender GVL can be either
chosen from a selection list of all available GVLs within the network, or it can be
read from an export file, which previously has been generated (for example by
using the Link to File Properties dialog) from the GVL. Definitely an export file will
be needed, if the sender GVL to be used is defined within another project.
As a precondition for network variables exchange the respective network libraries
must be installed, which e.g. is done automatically for the standard network type UDP
as soon as the network properties for a GVL are set.
Example:
In the following example a simple network variables exchange will be established. In
the sender device a GVL is created and in the receiver device the corresponding GNVL:
Preparatory work in a standard project, where a sender device "Dev_Sender" and a
receiver device "Dev_Receiver" are available in the devices tree:
- Create a POU (program) 'prog_sender' below 'Application' of 'Dev_Sender'.
- In the Task Configuration of this application add task 'Task_S' calling 'prog_sender'.
- Create a POU (program) 'prog_receiver' below 'Application' of 'Dev_Receiver'.
- In the Task Configuration of this application add task 'Task_R' calling 'prog_receiver'.