6.5.2
Setting a send cycle clock and system cycle clocks
6.5.2.1
Basic principles
Basic cycle clock
For the SIMOTION D4x5-2, the basic cycle clock depends on:
● Whether a second servo task has been activated for the runtime system.
● Whether a second PROFINET interface (=CBE30‑2) is used for the SIMOTION D4x5-2 DP/
PN.
By default, one servo task and two IPO tasks (IPO, IPO_2) are used. The IPO_2 cycle clock
can be set as a multiple of the IPO cycle clock. In this way, the IPO_2 cycle clock can be used
for lower priority technology objects (e.g. axes with less dynamic response).
Second servo task
A second servo task is only required for applications with special requirements, e.g.:
● For fast I/O processing via PROFINET IO (for particularly short sampling times and
response times).
● If in addition to the electric axes (e.g. servo drives), hydraulic axes with particularly high-
performance pressure/position control are implemented.
● If the electric axes have to be split into two performance classes on the servo level (fast
servo - slow servo).
Note
If the axes have to be split into two performance classes, usually a split on the IPO level (IPO,
IPO_2) is sufficient, a split on the servo level (Servo, Servo_fast) is only required in exceptional
circumstances.
- The reference variable calculation / motion profile calculation of the axes is performed in the
IPO level.
- The position control and monitoring of the axes is performed in the servo level.
Note that an additional Servo_fast/IPO_fast places an extra load on the SIMOTION runtime
system.
In addition, with DSC (Dynamic Servo Control) for servo axes, the dynamically effective part
of the position controller in the drive is performed in the frequency of the speed control loop
(i.e. usually with 125 µs in the case of SINAMICS S120). If symbolic assignment with automatic
telegram determination is used, DSC is activated automatically.
Parameter assignment / addressing
6.5 Configuring PROFINET IO
SIMOTION D4x5-2
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Commissioning and Hardware Installation Manual, 03/2018, A5E33441636B
