User`s manual

256
(1) Reception with the first frame (combination 1-A to C) (reception using Format-
0)
(a) Reception of combination (1-A)
• In this method, any data section of the reception message that can be handled by the programmable
controller CPU side is enclosed by the first frame and the last frame and transmitted from the external
device.
• Any reception data prior to the first frame will be ignored.
• The Q series C24 will begin reception processing when data of the same arrangement as the first frame 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.
• Reception processing via the receive complete code initially set in the Q series C24 will not be performed.
The reception data for the receive complete code will be treated as arbitrary data.
When data transmitted from a bar code reader is received
STX will be registered in the first frame and ETX registered in the last frame according to the message
format of the bar code reader.
(b) Reception of combination (1-B)
• In this method, messages to be received by the programmable controller CPU side are all transmitted from
the external device as fixed format data.
• Any reception data prior to the first frame will be ignored.
• The Q series C24 will begin reception processing when data of the same arrangement as the first frame is
received. When data of the same arrangement as the last frame is received, a read request is performed to
the programmable controller CPU.
• Since there is no arbitrary data, the reception data count will be "0" when a read request is performed to the
programmable controller CPU.
• The received data count initially set in the Q series C24 uses the default value.
02H 03H
E
T
X
S
T
X
(Data format transmitted from the bar code reader)
Data (arbitrary data)
Reception
data
Ignored
: Reception start timing
: Receive complete timing (read timing)
Stored in the reception area
First frame: STX
Last frame: ETX
06H 0AH0DH
A
C
K
C
R
L
F
Ignored
: Reception start timing
: Receive complete timing (read timing)
First frame: ACK
Last frame: CR, LF
Stored in the reception area
The received data count is "0."
Reception
data