Mitsubishi Electric MELSEC iQ-R Series User Manual page 331

Processing order for transmitting/receiving data
The processing steps taken by C24 to transmit/receive data by the transparent code designation and ASCII-BIN conversion
enabled are as shown below.
■Data reception in arbitrary format
• C24 deletes (removes) the additional code designation data when a transparent code for receiving is specified.
• C24 stores the arbitrary data portion in the receive area on the buffer memory.
When ASCII-BIN conversion is designated, C24 converts it to binary code data and stores in the buffer memory.
• C24 issues a reception data read request to the CPU module when the receive end code data is stored or data equivalent
to the receive end data quantity is stored during reception of an arbitrary data portion.
■Data transmission in arbitrary format
• C24 transmits the data to be sent (arbitrary data portion of a transmission message), which is designated by the CPU
module.
When ASCII-BIN conversion is designated, C24 converts it to ASCII code data and transmits it.
• C24 adds the additional code data immediately before the transparent code/additional code data, and transmits it when a
transparent code for sending is specified.
• C24 notifies the CPU module of the transmission normal (abnormal) completion once transmission for the send data
quantity has been completed.
Target device C24
(Transparent code designation)
Data
transmission Adding
additional
code
No
Data
reception
Yes
Ex.
When ASCII-BIN conversion is not performed
Target device
Arbitrary data
D
L
E
12 10
H H
(For 10H)
(ASCII-BIN conversion designation)
No
ASCII-BIN
conversion of
Yes
transmission
data
No
ASCII-BIN
Delete
conversion of
Yes
additional
arbitrary data
code
section
(Communicating in an arbitrary format)
Head data
02 3A BC
H H H
Transparent code
(For 02H)
Additional code
16.3 Handling Transparent and Additional Codes for Nonprocedural Protocol Data Communication
No
Yes
Check receive
complete code
and received
data count
Buffer memory (transmission area/reception area)
Send
Receive
16 TRANSPARENT CODES AND ADDITIONAL CODES
Buffer memory
Transmission
area data
Data to be stored
in the reception
area
C24
(H) (L)
Transmission data
(0002H)
count/Receive data
00H , 02H
count
(0212H)
02H , 12H
Transmission data/
(BC3AH)
receive data
BCH , 3AH
(The data count is in word units)
16
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