Lenze E94AxPExxxx - Manual (Page 54)

4 PLC functionality
4.5 Use of system blocks
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Lenze · 9400 Servo PLC· Reference manual · DMS 4.0 EN · 11/2013 · TD05/06
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4.5 Use of system blocks
Functions used for implementing applications for Lenze controllers are described by means of
function blocks (FBs).
• Functions which can be used in your project as software functions are included in the function
libraries as function blocks or functions.
• Moreover, there are quasi hardware functions which are available as system blocks (SBs) in the
»PLC Designer« control configuration.
Principle
The principle of the system blocks can be explained with the help of a PLC system in a rack: The rack
contains the CPU, digital I/Os, analog I/Os, counter cards, positioning cards etc. as additional cards.
• The CPU can directly access the extension cards and process the resulting information.
• The single extension cards have a permanent address for being addressed.
With the »9400 ServoPLC«, the system blocks comply with these additional cards! Thus, system
blocks are special (hardware) function blocks that are permanently implemented in the runtime
system of the »9400 ServoPLC«.
• SBs can address real hardware.
• SBs are assigned/identified by node numbers.
• The inputs/outputs of the SBs are accessed via system variables or absolute memory addresses.
• Inputs/outputs are always classified from the program's point of view.
• Required SBs must be explicitly implemented into the project via the control configurations of
»PLC Designer«.
 Additional cards
CPU
0 0 0 0 0 0 0