13 CONTENTS AND REGISTRATION OF USER FRAMES FOR DATA COMMUNICATION
13.1 User Frame Types and Contents During Communication
251
13
User frame registration
Up to 80 bytes (80 characters) of data can be registered as 1 user frame.
Up to 231 user frames can be registered (written), read, and deleted to/from C24.
*1 For the priority of the registered data, refer to the following section.
Page 401 PARAMETER REGISTRATION TO CPU MODULE
Registration data to handle variable data (Sum check code, C24 station number, etc.) as a part of the user frame can be
included in the user frame. (Page 251 Variable data)
User frames can be registered by overwriting to C24 buffer memory. (The preceding contents are destroyed.)
Data that can be registered as user frame
Up to 80 bytes of data can be registered by combining 1 byte data of which registered code is 01H to FEH and 2 bytes data of
which registered code is FFH + 00H to FFH + FFH.
■One byte data of which registered code is (01H to FEH)
This is the registered code for transmitting and receiving the data of which registered code is (01H to FEH).
■Two bytes data of which registered code is (FFH + 00H) to (FFH + FFH)
This is the registered code for transmitting and receiving the variable data (sum check code, C24 station number, etc.) as part
of the user frame. (Page 251 Variable data)
FFH is the registered code of the first byte for handling variable data.
Variable data
"Variable data" is a generic term for the data shown below.
These variable data can be handled as part of a user frame.
• Sum check code covering a determined range of messages to be transmitted/received
• Horizontal parity code covering a determined range of message to be transmitted/received
• Two's complement sum check code covering a determined range of messages to be transmitted/received
• C24 station number
• One byte data in data transmission (00H (NULL), FFH)
• One byte of arbitrary data in data reception. (Used to handle an arbitrary byte of data as part of the user frame during
reception check by C24.)
■Variable data designation method
Variable data is designated by combining registered code FFH and the data codes shown in the table below.
The sum check code, C24 station No., and other variable data can be handled according to FFH of the first byte and 00H to
FFH of the second byte.
Registration destination Maximum
number of
frames can be
registered
Frame No. Application Remarks
CPU module Built-in memory
*1
31 frames 8001H to
801FH
A user frame of which contents are changed
after data communication has started
SD memory card
*1
31 frames 8001H to
801FH
A user frame of which contents are changed
after data communication has started
C24 Flash ROM
*1
200 frames 03E8H to
04AFH
A user frame of which contents is not changed
after data communication has started
Buffer memory 31 frames 8001H to
801FH
A user frame of which contents are changed
after data communication has started
Registration by
overwriting with MOV
instruction is available.
FFH
00H to FFH
2nd byte
1st byte
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