Panasonic AFP7CCET1, Руководство пользователя

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6.4 Sending/Receiving Flag Operation
KEY POINTS

The data without the Code STX at the reception is saved in the reception
buffer, and the “reception done” flag turns on when the end code is
received.

However, if the code STX is added in the middle of the data, the data are
saved from the beginning of the reception buffer.
Sending process: Sending done flag and GPSEND instruction are related as follows:
STX
ETX ETX STX
a
b
c d e
ON
OFF
ON
OFF
b
a
STX
ETX
b
a
STX
ETX
b
a
STX
ETX
b
a
STX
ETX
d
e
c
STX
ETX
d
e
c
STX
ETX
d
e
c
STX
ETX
d
e
c
STX
ETX
d
e
c
STX
ETX
Transmitted
data
SCU
send buffer
GPSEND
instruction
execution
T
rans
m
is
s
ion poi
nt
er
General-purpose
communication
Sending active flag
Y8

Header (STX) and terminator (ETX) are automatically added to the data to be sent. The data
are transmitted to an external device.

After GPSEND instruction is executed, data transmission is started in several
μ
s to several
tens of ms. For time before transmission is started, please refer to the communication cycle
time (SM208-SM210) using the system monitor function.

After GPSEND instruction is executed, dual sending to the same port is not possible until the
"sending general-purpose communication flag" (Y8) turns OFF.

The "General-purpose communication Sending active flag" (Y8) turns OFF in GPSEND
instruction execution in the next scan or later following completion of data sending to an
external device. The "General-purpose communication Sending active flag" (Y8) always
remains on for at least 1 scan time.
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