When Receiving Data Whose Length Is An Odd Number - Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual

Ex.

When receiving data whose length is an odd number

(Word)
Data length storage area + 0
Data storage area + 1
+ 2
+ 3
(Word)
Data length storage area + 0
Data storage area + 1
+ 2
+ 3
When unit of stored data is "Lower Byte Only"
• A size double the data length is occupied. For the upper data, the Ethernet-equipped module ignores the data at sending
and adds 00H to the data at receiving.
Non-verified reception
The usage examples for a non-verified reception element is shown below.
Ex.
Example of a packet format of the external device
Necessary information for users
1 byte 2 bytes
Identification
STX
code
Example of a packet setting
2 bytes 2 bytes
Non-conversion
Static data
variable
In the above type of packet format, the following operation can be executed by setting reception without verification.
• It is possible to store only the required information in the CPU module's device or buffer memory.
• Even if the received packet contains data that changes with each communication, it can be handled with one protocol
(packet).
No byte swap
Specified device
0005H
0201H
0403H
0005H
Specified device
Byte swap
0005H
0102H
0304H
0500H
2 bytes 5 bytes
Country Manufacturer
code code
Reading data
Non-verified reception is
set in the elements.
Variable number of characters
Non-verified reception (variable number of characters)
Appendix 10 Operation Image and Data Structure of Predefined Protocol
Receiving
01H 02H
Variable number of
5 bytes
characters
Product
code
When the information is unnecessary
for users and the data
(including the number of characters)
are variable
External device
Send data
03H 04H 05H
1 byte
EXT
1 byte
Static data
APPX
A
403