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Bosch Rexroth AG
MLD communication interfaces and data channels
Motion task in synchronism with
master communication without
MLD-M system mode
No motion task in synchronism
with master communication
Motion task in synchronism with
master communication with MLD-
M system mode
The data of the "AxisData" structure are only fully available if the
drive is in phase 4. Otherwise, "Axis_Error" is the only element
that is set for error diagnostics, provided an error is pending at the
corresponding axis.
Note the following when using a motion task in synchronism with
master communication in conjunction with the MLD-M system
mode: Consistent data access to the "AxisData" structure is im‐
possible, since the motion task in synchronism with master com‐
munication runs synchronously with the NC cycle and, in this in‐
stance, not synchronously with the CCD cycle, although the "Ax‐
isData" structure is processed synchronously with the CCD cycle.
Validity and consistency of "AxisData" structure data
The data (command values and actual values) are centrally contained in a
global array.
When using a motion task in synchronism with master communication (see
chapter "Basic functions of Rexroth IndraMotion MLD", section
tem"), the "AxisData" structure is processed synchronously to the NC clock
and thereby synchronously to the motion task in synchronism with master
communication, i.e., the actual values are updated after the time T4 (T4 is the
time when the actual values are latched for the drive telegram [AT]). This
makes the actual values available at the start of the motion task.
Once the task has ended, the command values of the "AxisData" structure
are written directly before the master data telegram is evaluated, i.e., the
command values from the "AxisData" structure become valid at the same
time as the command values from the MDT from the higher-level, potentially
synchronizable sercos III master. If the drive is connected to a master com‐
munication other than sercos III, the drive synchronizes itself in the NC cycle
interval. The NC cycle time is set via the parameter S-0-0001. This does not
change the generation of the axis data structure. Consistent data from the
"AxisData" structure are available within the motion task in synchronism with
master communication.
If other tasks access the axis data structure, the actual values and command
values should be read or written at the beginning of the task, if possible. The
consistency of the data of the "AxisData" structure cannot be guaranteed in
this case.
If no motion task in synchronism with master communication is used, the "Ax‐
isData" structure is processed at the beginning and end of a PLC time slice
(see chapter "Basic functions of Rexroth IndraMotion MLD", section
system"), i.e., the actual values are updated directly before the start of a new
time slice and the command values are written directly after the end of the
PLC time slice. Accessing data consistently with the "AxisData" structure is
only possible if the "AxisData" structure is used in a cyclic task with the small‐
est periodic time; this cannot be done in any other instance.
When using a motion task in synchronism with master communication (see
chapter "Basic functions of Rexroth IndraMotion MLD", section
tem") when MLD-M system mode is active, the "AxisData" structure is
synchronized to the CCD cycle, i.e., the actual values of the "AxisData" struc‐
ture are updated each time a CCD AT is processed. This means the actual
values of the "AxisData" structure are updated when all actual values of the
CCD slave axes, which were transmitted via the corresponding drive tele‐
gram, are known to the CCD master axis.
LSA Control S.L. www.lsa-control.com comercial@lsa-control.com (+34) 960 62 43 01
DOK-INDRV*-MLD3-**VRS*-AP02-EN-P
Rexroth IndraDrive Rexroth IndraMotion MLD (2G) as of MPx-18
"Task sys‐
"Task
"Task sys‐
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