Mitsubishi Electric MELSEC iQ-RJ71C24-R4 - Page 331

16 TRANSPARENT CODES AND ADDITIONAL CODES
16.3 Handling Transparent and Additional Codes for Nonprocedural Protocol Data Communication
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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.
Ex.
When ASCII-BIN conversion is not performed
Target device C24
(Transparent code designation)
(ASCII-BIN conversion designation)
No No
Buffer memory
Data
transmission
ASCII-BIN
conversion of
transmission
data
Adding
additional
code
Transmission
area data
Yes Yes
No No
Data
reception
ASCII-BIN
conversion of
arbitrary data
section
Check receive
complete code
and received
data count
Delete
additional
code
Data to be stored
in the reception
area
Yes Yes
10 H 02 H 3A H BC H 12 H
D
L
E
(H) (L)
(0002H)
(0212H)
(BC3AH)
00H , 02H
02H , 12H
BCH , 3AH
C24
Target device
(Communicating in an arbitrary format)
Buffer memory (transmission area/reception area)
Head data
Additional code
Transmission data
count/Receive data
count
Arbitrary data
Send
Transmission data/
receive data
Delete
Addition
Receive
(The data count is in word units)
Transparent code
(For 02H)
Additional code
(For 10H)