Specifications

209PLC Code for PROFINET Controller

The automatic refresh executed by the Qn-CPU automatically copies the output contents from the

buffer devices to the transfer buffers in shared memory and the input contents in the opposite directi-

on. The global variables reference these buffer devices. Thus a read/write access by the PLC pro-

gram to a global variable equals a read/write access to the respective buffer device.

The following diagram shows the relation between transfer buffers, devices and global variables.

With the default buffer device addresses as shown in the previous screenshot the export PLC code

contains the following global variable definitions:

Identifier

Type

vPN_MGMT_OUTPUT