SIEMENS
2/57
Siemens PM 21 · 2017
SIMOTION Motion Control System
SIMOTION runtime software
SIMOTION Kernel
2
■
Function
(continued)
The following execution levels are available to the application:
StartupTask
The StartupTask is executed once at the operating mode
transition from STOP to RUN; it controls the system start-up.
BackgroundTask
The BackgroundTask is executed cyclically and is used for
general PLC tasks. Cycle time monitoring checks the maximum
processing time of the BackgroundTask. The BackgroundTask
can be compared with the OB1 of a SIMATIC controller.
MotionTasks
MotionTasks are used for motion sequences.
Command sequences in the same Motion Task are usually
executed sequentially, for example, the next motion command is
only started when the previous command has been completed.
The MotionTasks do not require any CPU time during these
waiting times, but respond immediately on receipt of the wait
event.
SynchronousTasks
In servo-synchronous user tasks, time-critical terminal-to-
terminal responses for I/Os or fast influencing of setpoints can
be implemented on the servo level (synchronous to the system
cycle SERVO of the technology objects, e.g. position
controllers).
The IPO synchronous user tasks are started synchronously
immediately before the interpolator cycle IPO or the slower IPO2.
Fast Motion Control reactions can be implemented here, as well
as closed-loop control tasks in which the acquisition of actual
values and output of setpoints must be synchronized.
The characteristic variables for the technology objects are
calculated in system cycles IPO and IPO2.
The user program is therefore synchronized with the control
cycle of the drives and with I/O processing. Synchronization
ensures short response times and, above all, deterministic and
reproducible machine behavior.
DCC tasks
Drive Control Chart (option) uses the above-mentioned
SynchronousTasks. In addition, further synchronous execution
levels (special tasks for DCC) can be assigned to the blocks.
TimerInterruptTasks
Several time-triggered tasks are available. The call cycles can
be parameterized. Periodically repeated tasks are normally
placed here.
InterruptTasks
InterruptTasks are used for a fast response to internal events that
are signaled using interrupts. InterruptTasks can be activated by
system interrupts, such as alarms and timeouts, or by user
interrupts.
ShutdownTask
The ShutdownTask is called when there is a transition to STOP
mode. The specific behavior for the transition into this system
state can be defined here.
The complete instruction set is available for all user tasks. This
allows the current positioning command from a MotionTask to be
superimposed with an additional movement which was triggered
by a UserInterruptTask, for example.
Runtime levels of the technology packages
The execution cycle can be set object-specifically for Motion
Control technology objects.
Technology objects are executed in the execution levels SERVO
cycle and IPO cycle or IPO2 cycle that are synchronized with the
PROFINET or PROFIBUS cycle.
•
Command evaluation and motion control in the IPO/IPO2
cycle
•
Position and setpoint control in the SERVO cycle
•
IPO/IPO2 cycle can be reduced relative to the SERVO cycle to
allow optimization of the system's performance to meet
requirements.
The SIMOTION D435-2 DP/PN, D445-2 DP/PN and
D455-2 DP/PN Control Units have an additional runtime level
(SERVO
Fast
, IPO
Fast
).
This additional runtime level enables the performance of the
controller to be utilized more efficiently. Electrical and/or
hydraulic axes can be distributed over one slow and one fast
bus system depending on the dynamic response required.
Electrical positioning drives, for example, can be controlled with
cycle times in the millisecond range requiring fewer resources
and, at the same time, the pressure-controlled axes of an
hydraulic press can be controlled highly dynamically with short
cycle times.
The runtime level (SERVO
Fast
, IPO
Fast
) also enables a
particularly fast I/O processing in conjunction with, for example,
high-speed PROFINET I/O modules.
Further characteristics of the execution system
•
Operating states – Run, Stop, StopU (Stop User Program for
test and commissioning functions)
•
Process images for inputs/outputs, is separate for
BackgroundTask, SynchronousTasks and TimerInterruptTasks
•
Debug functions such as
- Controlling and monitoring of variables
- Display of the program status
- Breakpoints and single step
- Trace functions
•
Kernel updates can be implemented with new SCOUT
versions.
© Siemens AG 2017