User`s manual

259
CHAPTER 11 DATA COMMUNICATIONS USING USER FRAMES
11
11.2 Data Reception
(3) Reception without the first frame (combination 2-A, 2-B) (reception using
Format-0)
(a) Reception of combination (2-A)
• In this method, a user frame is used as the last frame in place of the non procedure protocol data receive
complete code and is transmitted from the external device together with arbitrary data.
• Any reception data prior to the last frame are all treated as arbitrary data.
• The Q series C24 will begin reception processing when arbitrary data is received. When data of the same
arrangement as the last frame is received, arbitrary data is stored in the reception area of the buffer memory
and a read request is performed to the programmable controller CPU.
• The received data count initially set in the Q series C24 should be a data count that exceeds the size of the
arbitrary data to be received.
• The Q series C24 performs the following processing with respect to the reception data that is the same as
the receive complete code initially set in the Q series C24.
• When the reception data is included in the arbitrary data: Reception is processed via the receive complete
code.
• When included in the last frame: Reception is not processed via the receive complete code.
By registering ETX + CR + LF as the last frame, a read request is performed to the programmable
controller CPU when the end of the reception data receives a message of ETX + CR+ LF.
03H 0AH0DH
E
T
X
C
R
L
F
Arbitrary data
Last frame: ETX, CR, LF
: Reception start timing
: Receive complete timing (read timing)
Stored in the reception area