ABB RECA-01, User Manual

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Communication
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Logical addressing
The slaves are not addressed individually, but instead a section of
the segment wide 4 GB logical address space is addressed. This
section may be used by any number of slaves.
Fieldbus Memory Management Units (FMMUs) handle the local
assignment of physical slave memory addresses to logical
segment wide addresses. The slave FMMUs are configured by the
master. Each FMMU configuration contains a logical start
address, a physical memory start address, a bit length and a type
that specifies the direction of the mapping (input or output).
RECA-01 has four FMMUs. The EtherCAT® master can use them
for any purpose.
Sync managers
Sync managers control the access to the application memory.
Each channel defines a consistent area of the application
memory. RECA-01 has four sync manager channels. Their
functions are described below. The mailbox protocol and process
data are described later in this chapter.
Sync manager channel 0
Sync manager 0 is used for mailbox write transfers (mailbox from
master to slave). The module supports mailbox sizes between
50…256 bytes. The default is 192 bytes.
Sync manager channel 1
Sync manager 1 is used for mailbox read transfers (mailbox from
slave to master). The module supports mailbox sizes between
50…256 bytes. The default is 192 bytes.
Sync manager channel 2
Sync manager 2 is used for process output data. It contains the
Rx PDOs specified by the PDO assignment object 0x1C12 (hex).