Lenze ECSCAxxx - Manual (Page 21)

Preface and general information
System block introduction
System blocks ˘ principle
1
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21 EDBCSXA064 EN 3.2
1.5 System block introduction
Lenze pursues the principle to describe functions of the controller by means of function
blocks (FB). This principle is also described in the standard IEC 61131−3.
ƒ Functions that you can use in your project as software functionalities, are contained
in the function libraries as function blocks or functions.
ƒ Moreover, quasi hardware functions are available as system blocks(SB).
1.5.1 System blocks ˘ principle
ƒ System blocks partly respond to real hardware.
ƒ The system blocks are assigned/identified via node numbers. (
¶ 22)
ƒ The inputs/outputs of the system blocks are assigned via:
– System variables (
¶ 23)
– Absolute memory addresses (
¶ 24)
ƒ Inputs/outputs are always classified from the program’s point of view.(
¶ 24)
ƒ Required system blocks must be explicitly integrated into the project of the DDS via
the control configuration. (
¶ 26)
The system block principle can be perfectly explained by means of a PLC system in a rack:
ƒ Besides the CPU, the rack includes digital I/Os, analog I/Os, counter cards,
positioning cards etc. as extension cards:
CPU x x x x x x
x = extension cards
ƒ The CPU can directly access the extension cards and process the resulting
information.
ƒ The single extension cards have a permanent address for being addressed.
I
Tip!
In case of the ECSxA... axis modules, the system blocks correspond to these
attachment cards!
System blocks therefore are specific (hardware) function blocks which are
firmly integrated into the runtime system of the ECSxA... axis module.