General-Purpose Communication
9-16
After GPSEND instruction is executed, dual sending to the same port is not possible until the
"sending General-purpose communication Sending active flag" (Y8, Y9, YA, YB) turns OFF.
The "General-purpose communication Sending active flag" (Y8, Y9, YA, YB) turns OFF in
instruction execution in the next scan or later following completion of data sending.
9.5.2 Start Code "STX", End Code "ETX":
Receiving process: Reception done flag and GPRECV instruction are related as
follows:
A
B
C
STX
D
H
ETX
E
ETX
F
G
STX
E
D
2
ON
OFF
ON
OFF
A
A
B
B
C
A
B
C
A
G
F
G
H
G
H
<1>
<2>
<3>
<0>
<0>
<1>
<1>
B
C
D
<1>
E
C
D
<2>
E
C
D
<2>
G
F
<2>
F
<1>
Data received
from external
device
SCU
receive bu ffer
No. of bytes
received
W
rit
e
p
o
in
te
r
Receive bu ffer
specified using
GPRECV instruction
GPSEND
instruction
execution
No. of bytes received
Reception
done flag
X0, X1, X2, X3
Upon reception of the
start code, the reception
pointer is initialized.
Upon reception of the
start code, the reception
pointer is initialized.
Even in a
"reception done"
status, received
data is continued
into another
buffer, because
there are 4,096 x
8 reception
buffers.
Stored
When the start code is set to "STX", the data are saved in the reception buffer. When the
start code is received, the receive pointer is initialized. If there are two headers, data
following the second header overwrites the data in the reception buffer.
The COM port has eight reception buffers. The reception process is continued after the
reception done flag (X0, X1, X2, X3) turns ON. The reception done flag (X0, X1, X2, X3)
does not turn OFF immediately following the execution of GPRECV instruction. It will be
turned off at the beginning of the next scan or later.
If there are no received data following execution of GPRECV instruction, the reception done
copy flag (X4, X5, X6, X7) turns OFF.
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.
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.clrwtr.com - Email: [email protected]
Содержание AFP7CCM1
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Страница 10: ...Table of Contents viii Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Страница 21: ...2 Names and Functions of Parts Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Страница 24: ...Names and Functions of Parts 2 4 Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Страница 25: ...3 Wiring the COM Port Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Страница 45: ...3 I O Allocation Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Страница 52: ...I O Allocation 4 8 Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Страница 57: ...6 PLC Link Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Страница 97: ...9 General Purpose Communication Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Страница 114: ...General Purpose Communication 9 18 Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Страница 115: ...4 Troubleshooting Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Страница 124: ...Troubleshooting 10 10 Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
Страница 125: ...11 Specifications Phone 800 894 0412 Fax 888 723 4773 Web www clrwtr com Email info clrwtr com ...
