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APPX
Appendix 10 Operation Image and Data Structure of Predefined Protocol
■Data flow
Data flow is used to specify the order of send data and receive data.
The data flow can be specified in forward direction (upper byte lower byte), reverse direction (lower byte upper byte),
and byte swap (by word).
• Forward direction, reverse direction: Available when the data length is 2 bytes or more.
• Byte swap: Available only when the data length is 4 bytes.
■Calculating range
Examples of specifying the length calculating range are shown below.
Non-conversion Variable
■Process procedure
The Ethernet-equipped module processes the non-conversion variable element with the following procedure.
When unit of stored data is "Lower Byte + Upper Byte"
• When the data length of a send packet is an odd number, the upper byte (lower byte when bytes are swapped) of the end
device is not sent.
• When the data length of a receive packet is an odd number, the last data is stored with one byte of 00H.
When sending data whose length is an odd number
Example 1:Calculating range when start of range is set as 3 and end is set as 3
Example 2:Calculating range when start of range is set as 3 and end is set as 30
Example 3:Calculating range when start of range is set as 1 and end is set as 32
Length
Packet format
Example 1
Example 2
Example 3
Packet
element 1
Packet
element 2
Packet
element 3
Packet
element 30
Packet
element 31
Packet
element 32
Static dataStatic dataStatic data
Non-conversion
variable
Static data
Calculating
range for
the length
Calculating range for the length
Calculating range for the length
03H04H 01H02H05H06H
04H03H 02H01H06H05H
0005H
0201H
0403H
0605H
+ 0
+ 1
+ 2
+ 3
External device
No byte swap
(Word) Specified device
Byte swap
Sending
Data length storage area
Data storage area
Send data
↑
Data are not sent.
↓
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