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DOK-INDRV*-MLD3-**VRS*-AP02-EN-P
Rexroth IndraDrive Rexroth IndraMotion MLD (2G) as of MPx-18
4.5.7
Task configuration
4.5.8
Task cycle times and timing
PLC cycle time
PLC time slice
Minimum PLC cycle time
Event task reaction times
Timing
Current
clock
Performance [µs]
(T
A_current
Basic
125
Advanced
62.5
LSA Control S.L. www.lsa-control.com comercial@lsa-control.com (+34) 960 62 43 01
The above figure shows a measurement of a task with a periodic time of
t#1ms. In this case, the task uses more than the specified interval time. The
100% mark again corresponds to the net time intended for the task within one
millisecond. Here the task requires more time, so the measured percentage
value at the "rLoad" output displays more than 100%. The "rFreeTime" output
displays 0 (µs).
It is possible, but not necessary, to control the processing of the project (con‐
trol of the program) via tasks; if there is no task configuration available, the
project has to contain the "PLC_PRG" function block. In this case, a default
task with a periodic time of 10 ms and a watchdog is automatically created.
As soon as the user has defined a task, this default task is deactivated.
The PLC cycle time T
The T
consists of one or several PLC time slices.
PLC
The integrated PLC (IndraMotion MLD) works cyclically in time slices, regard‐
less of the task type used. Since the integrated PLC is calculated by the drive
processor, it must share the resources with the rest of the system (position
controller, velocity controller, current controller, different background tasks
[such as command task], etc.). Depending on the system load, a certain cal‐
culating time is available to the MLD for each PLC time slice. All PLC IEC
tasks run in the context of PLC time slices.
The minimum PLC cycle time (T
the reaction time of the event tasks. The minimum PLC cycle time (T
does not depend on the control unit and is 1 ms.
The maximum configurable cycle time is 2000 s (or 33 minutes)!
See also Functional Description of firmware "Performance data"
Event tasks are also started within the PLC time slices, i.e., their reaction
time also depends on the PLC cycle time.
The attainable program cycle time or timing depends on the integration of the
PLC in the task system of the drive.
The performance of devices with MPB-18 and MPC-18 firmware can be
modified by the setting in P-0-0556:
●
P-0-0556, bit 2="0" ⇒ Basic performance
●
P-0-0556, bit 2="1" ⇒ Advanced performance
If the "MLD-M system mode" has been configured in the MPC
firmware (P-0-1800.0.1), the "Advanced" performance level is un‐
available.
controller
Velocity
controller
clock
)
(T
)
A_velocity
250
125
Tab. 4-6:
Performance settings (performance level)
The figures below illustrate the functional principle (interruptions by velocity
controller, current controller, etc., are not shown):
Basic functions of Rexroth IndraMotion MLD
of MLD defines the periodic time for cyclic tasks.
PLC
) is one PLC time slice; it also defines
PLC,min
Position
controller
PLC
cycle
clock
(IndraMotion MLD)
(T
)
[T
]
A_position
MLD
500
1000
250
1000
Bosch Rexroth AG
69/267
PLC,min
time
Master
communication
cycle time
(T
)
MastCom
500
250
)
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