Omron CJ1W-PNT21 Operation Manual page 120

Configuring the IO Controller
Data Type
OctetString
VisibleString
Integer Conversion
106
Size PROFINET IO
[bytes]
-- Supported
Data is transmitted on byte by byte basis
-- Supported
Data is transmitted on a Most-Significant-
Byte First basis
The figure below shows each of the formats both on the PROFINET IO
network and in the PLC data area. The data bytes on the PROFINET IO
network are transmitted in the sequence shown in the figure, i.e. Byte 0 is
transmitted and received first, after that byte 1, etc. The PLC data is stored in
word-sized locations, word 0 at the lowest address, word 1 at the next higher
address, etc.
Bit 15
Word 0
Word (n+1)/2
Bit 15
Word 0
Bit 15
Word 0
Word 1
The following format conversions are required:
1 A sequence of 8-bit bytes, either signed or unsigned must be mapped to
the PLC data area words on a low-byte/high-byte sequence. If the number
of bytes is even, all bytes will fit in the words. If the number of bytes is odd,
the last byte of the sequence will be mapped to the low-byte of the last
word. The high-byte of the last word must be padded with a 0.
2 A 16-bit word or a sequence thereof, either signed or unsigned must be
mapped to the PLC data area words on a high-byte/low-byte sequence.
3 A 32-bit double word or a sequence thereof, either signed or unsigned
must be mapped to the PLC data area words on a high-byte/low-byte
sequence as well as on a high-word/low-word sequence.
PLC Data area
Bit 00
Byte 1 Byte 0
Byte n Byte n-1
PLC Data area
Bit 00
Byte 0 (MSB) Byte 1 (LSB)
PLC Data area
Bit 00
Byte 2 Byte 3 (LSB)
Byte 0 (MSB) Byte 1
Figure 7.17: Data conversion
CJ-Series PLC
Supported
Minimum is 16-bit words. Two bytes will be
formatted in one word. Words containing
odd bytes will be padded with zeros
Supported
Single 16-bit integers are transferred to
memory words in PLC memory.
PROFINET
Bit 07 Bit 00
Byte 0
Byte 1
Byte n-1
Byte n
PROFINET
Bit 07 Bit 00
Byte 0 (MSB)
Byte 1 (LSB)
PROFINET
Bit 07 Bit 00
Byte 0 (MSB)
Byte 1
Byte 2
Byte 3 (LSB)
Section 7-4
Byte
sequence
Word 0
Double Word 0