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Appendix |EtherCAT Documentation
confocalDT 24x1
A 6.1.3 Addressing and FMMUs
In order to address a slave in the EtherCAT® system, various methods from the master
can be used. The confocalDT 24x1 supports as full slave:
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Position addressing
The slave device is addressed via its physical position in the EtherCAT® segment.
The services used for this are APRD, APWR, APRW.
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Node addressing
The slave device is addressed via a configured node address, which was assigned by
the master during the commissioning phase.
The services used for this are FPRD, FPWR and FPRW.
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Logical addressing
The slaves are not addressed individually; instead, a segment of the segment-wide
logical 4-GB address is addressed. This segment can be used by a number of slaves.
The services used for this are LRD, LWR and LRW.
The local assignment of physical slave memory addresses and logical segment-wide
addresses is implemented via the field bus Memory Management Units (FMMUs). The
configuration of the slave FMMUs is implemented by the master. The FMMU configura-
tion contains a start address of the physical memory in the slave, a logical start address
in the global address space, length and type of the data, as well as the direction (input or
output) of the process data.
A 6.1.4 Sync Manager
Sync Managers serve the data consistency during the data exchange between Ether-
CAT® master and slaves. Each Sync Manager channel defines an area of the application
memory. The confocalDT 24x1 has four channels:
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Sync-Manager Channel 0: Sync Manager 0 is used for mailbox write transfers (mailbox
from master to slave).
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Sync-Manager Channel 1: Sync Manager 1 is used for mailbox read transfers (mailbox
from slave to master).
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Sync-Manager Channel 2: Sync Manager 2 is usually used for process output data.
Not used in the sensor.
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Sync-Manager Channel 3: Sync Manager 3 is used for process input data. It contains
the Tx PDOs that are specified by the PDO assignment object 0x1C13 (hex.).