Bosch Rexroth IndraMotion MLD Series, Руководство по применению, Страница: 63 / 270

4.5.3 Task properties
Periodic (cyclic) tasks Periodic ("cyclic") tasks have the following features:
●
Constant cycle time
● The cyclic task is started exactly once per specified period, i.e., the code
is run exactly once in every time interval, provided the previous run was
completed (in case of time overflow and activated watchdog, the PLC is
stopped with an "Exception" error status).
If a periodic task uses up the allocated calculating time and is still
active when it should already have restarted, it is not restarted be‐
fore the next period. This means the system does not attempt to
"make up" for the lost cycle.
Event tasks Event tasks have the following features:
●
Event tasks are started by setting a global Boolean PLC variable. The
start conditions are periodically checked, whereby the reaction times are
defined by the minimum possible PLC cycle time (see " Performance da‐
ta ").
● An event task is processed exactly once after the event (edge) occur‐
red.
External event task In principle, an external event task works like an event task; the difference
lies in how the task is activated. An external event task is activated via a sys‐
tem event. The user cannot influence system events.
The following two system events are supported:
●
FKM_SYNCHRONIZED_TASK
● CCD_SYNCHRONIZED_TASK
The external event task allows a motion task synchronized to the NC cycle or
a motion task synchronized to the CCD cycle to be implemented.
4.5.4 Motion task
General information
A motion task is a task synchronous to the NC or CCD cycle; the motion
function blocks and technology functions are normally processed in this task.
The real-time data of AxisData are calculated at the beginning and end of the
motion task.
Motion task in synchronism with master communication
The motion task in synchronism with master communication is a task
synchronized with the NC cycle.
It is created by an "external event" task with the system event
"FKM_SYNCHRONIZED TASK".
Motion task cycle time The motion task in synchronism with master communication runs synchro‐
nously with the NC cycle. The resulting motion task cycle time corresponds to
the NC cycle time.
The NC cycle time can be taken from parameter "S-0-0001, NC cycle time
(TNcyc)" (except for sercos III master communication). With sercos III master
communication, the NC cycle time corresponds to the "producer cycle time"
((S-0-1050.x.10) of the connection configured by the master in the MDT tele‐
gram.
DOK-INDRV*-MLD3-**VRS*-AP02-EN-P Bosch Rexroth AG 61/267
Rexroth IndraDrive Rexroth IndraMotion MLD (2G) as of MPx-18
Basic functions of Rexroth IndraMotion MLD
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