Ascii-Bin Conversion For Data Communicated With Bidirectional Protocol - Mitsubishi Electric MELSEC iQ-R Series User Manual

17.5
ASCII-BIN Conversion for Data Communicated
with Bidirectional Protocol
This section explains the ASCII-BIN conversion of data to be communicated using the bidirectional protocol.
Transmitted/received data range for ASCII-BIN conversion
The range of data to be sent/received to which ASCII-BIN conversion is performed is as shown below:
Ex.
Applicable data range at transmission/reception
E
N
Message at data Q
transmission/reception
A
C
K
Response message
C24 performs the following processing when sending or receiving data.
■At the time of data reception
Processing flow when a message is received during data reception
• C24 converts a received data length (4-digit ASCII code data (hexadecimal)) to 2-byte binary code data and stores it in the
receive data quantity storage area.
• C24 converts each two characters of a received data portion (2-digit ASCII code data (hexadecimal)) to 1-byte binary code
data and stores it in the receive data storage area.
• C24 calculates a sum check code using the received data length and data portion prior to ASCII-BIN conversion, then
checks the received head of the sum-check code using the code as a lower byte.
Processing flow when a response message is received
• C24 converts the first 2 digits of a received error code (4-digit ASCII code data (hexadecimal)) to 2-byte binary code data as
the lower byte, and stores it in the transmission result storage area. (When '1234' is received, it is converted to 3412H and
stored.)
■At the time of data transmission
Processing flow when a message is transmitted during data transmission
• C24 converts a data length (send data quantity) to 4-digit ASCII code data (hexadecimal), and sends it beginning with the
lowest byte (L).
• C24 converts a data portion (send data) for one address to 4-digit ASCII code data (hexadecimal), and sends it beginning
with the lowest byte (L).
• C24 calculates a sum check code using the data length and data section after ASCII-BIN conversion, and adds it to the
transmission message.
Processing flow when a response message is transmitted
• C24 converts an error code for a detected error to 4-digit ASCII code data (hexadecimal), then sends it beginning with the
lowest byte (L).
(For 3412H, it is converted to '3412' and sent beginning with '12'.)
(Arbitrary data)
Sum check
code
Data Data
length section
Applicable data range at transmission/reception
N
A
K
Error code
17 COMMUNICATING WITH ASCII CODE (ASCII-BIN CONVERSION)

17.5 ASCII-BIN Conversion for Data Communicated with Bidirectional Protocol

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