KUNBUS-COM EtherCAT
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Transmission block with fixed length
Command
code
(1 byte)
Address area
(2 bytes)
Data area
(2 byte)
Description
0x04
0x0000-0xFFFF
0x0000-0xFFFF
WRITE_WORD
0x00
0xXXXX
0xXXXX
NO_OPERATION*
The status response has the same structure and meaning as write
access with 1 byte
Writing more than 2 bytes
with one access (bulk-write)
This access type is suitable for larger volumes of data. The number
of target registers to be written and start address are transmitted with
the first transmission block. As with the previous access types, the
first transmission block also has a fixed length of 5 bytes here. After
this block with metadata, the user data follows in a separate
transmission block with variable length. The maximum permitted
number of target registers to be written depends on the target area: A
maximum of 128 registers (each 16-bit = 1 word) are permitted for
writing to the SSC input register area. A maximum of 16 registers per
block is to be written for all other target areas.
All 16-bit wide register contents to be written must be prepared by
the Master in such a way that the higher-value byte is transmitted as
the first byte and the lower-value byte is transmitted as the second
byte ("Big-Endian" or "Motorola format"). The register contents must
be sent in ascending address order, i.e. the start address first.
Transmission block with fixed length
Command
code
(1 byte)
Address area
(2 bytes)
Data length
(2 bytes)
Description
0x08
0x0000-0xFFFF
1-16/128
WRITE_BULK
0x00
0xXXXX
0xXXXX
NO_OPERATION*
NOTICE
The maximum data length for writing in the SSC input data area is 128
registers (256 bytes).
If this value is exceeded, errors in the data communication will result.
In the case of a transmission block of variable length, the module
sends bytes with the value 0 to the master.
The status response has almost the same structure and meaning as
write access with 1 byte. In the event of an error, a 16-bit wide
register address is at position 4 and 5 for this transmission type, at
which the first error occurred. The status is transmitted in the first
transmission block that follows the data block with variable length.
Components
