Mitsubishi Electric MELSEC iQ-R Series User Manual page 342

Precautions
The additional code data to be added/deleted is not included in the data length, nor will it be subject for sum check code.
Example of request data transmission when ASCII-BIN conversion is disabled
Message
E
Data length Data section
N
Q (0002H)
D D
L H
L L
E E
05H 10H 02H 00H 12H 10H
Processing order for transmitting/receiving data
■At the time of reception
• C24 deletes (removes) the additional code designation data from an arbitrary data portion 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.
• When the data portion for the designated data length is received, reading the received data is requested of the CPU
module.
If the sum check code is set to 'Yes' in the transmission setting via an Engineering tool parameter settings, reading the
received data is requested of the CPU module upon reception of the sum check code.
Target device C24
No
Data
(Arbitrary data section only)
reception
Yes
Response
transmission
Adding
additional code
(Error code section only)
■At the time of transmission
• C24 adds the transmission control code to the data to be sent (arbitrary data portion of a transmission message), which is
designated by the CPU module, and transmits it.
When ASCII-BIN conversion is designated, C24 converts it to ASCII code data at first and transmits it.
• When the sum check code is set to be enabled, C24 calculates the sum check code from the transmission message and
add it to the transmission message.
• C24 adds the additional code data immediately before the transparent code/additional code data in respect to arbitrary data
portion, and transmits it when a transparent code for sending is specified.
Target device C24
Data
(Arbitrary data section only)
transmission
Adding
additional code
Response
reception
Yes
No
The figure above shows how C24 processes the data to be transmitted/received when the ASCII-BIN conversion function,
and/or the data communication function by transparent code designation are enabled and disabled.
Use this information as a reference to select the method to send/receive data for data communication with a target device.
16 TRANSPARENT CODES AND ADDITIONAL CODES
340
16.5 Handling Transparent and Additional Codes for Bidirectional Protocol Data Communication
Additional code
Transparent code
Sum
Additional code
check
Transparent code : 02H
code
L H
02H 3AH BCH 0CH 01H
(Transparent code designation)
Deleting Deleting transmission
control code (ENQ)
additional code
Adding transmission
Yes
control code (ACK/NAK)
No
(Transparent code designation)
No
Adding transmission
Yes
control code (ENQ)
Deleting Deleting transmission
additional code control code (ACK/NAK)
(Error code section only)
Buffer memory
(H) (L)
: 10H
00H , 02H
02H , 12H
BCH , 3AH
(Sum check code setting)
No
Calculation and check of
Yes
sum check code
(Sum check code setting)
No
Calculation and check of
Yes
sum check code
Transmission data count/
Receive data count
Transmission data/
receive data
(ASCII-BIN conversion designation)
No
ASCII-BIN conversion of
Yes
data length, data section
ASCII-BIN conversion
Yes
of error code
No
(ASCII-BIN conversion designation)
No
ASCII-BIN conversion of
transmission data count
Yes
and transmission data
ASCII-BIN conversion
Yes
of error code
No
Buffer memory
Reception
area
Reception
result storage
area
Buffer memory
Transmission
area
Transmission
result storage
area