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334
Serial Communications
Section 6-1
6-1-2
No-protocol Communications
No-protocol communications enable sending and receiving data using the
TRANSMIT (TXD(236)) and RECEIVE (RXD(235)) instructions without using
a protocol and without data conversion (e.g., no retry processing, data type
conversion, or process branching based on received data). The communica-
tions mode for the serial port must be set for no-protocol communications in
the PLC Setup.
No-protocol communications are used to send data in one direction to or from
standard devices that have an RS-232C or RS-422A/485 port using TXD(236)
or RXD(235).
For example, simple (non-protocol) communications can be used to input data
from a barcode reader or output data to a printer.
The following table lists the no-protocol communication functions supported
by CP1H PLCs.
CP1H CPU Unit
TXD(236) or RXD(235)
Sending/receiving data
RS-232C or RS422A/485
Standard device with
serial communications
(e.g., barcode reader)
Transfer direction
Method
Max.
amount
of data
Frame format
Other functions
Start code
End code
Data transmission
(PLC
→
External device)
Execution of
TXD(236) in
the program
256 bytes
Yes: 00 to FF
No: None
Yes:
00 to FF or CR+LF
No: None
(The amount of data to
receive is specified
between 1 and 256 bytes
when no end code is speci-
fied.)
• Send delay time
(delay between
TXD(236) execu-
tion and sending
data from specified
port): 0 to 99,990
ms (unit: 10 ms)
• Controlling RS and
ER signals
Data reception
(External device
→
PLC)
Execution of
RXD(235) in
the program
256 bytes
Monitoring CS and
DR signals
Содержание CP1H-CPU - 05-2006
Страница 1: ...OPERATION MANUAL CP1H CPU Unit SYSMAC CP Series CP1H X40D CP1H XA40D CP1H Y20DT D Cat No W450 E1 02...
Страница 2: ...CP1H X40D CP1H XA40D CP1H Y20DT D CP1H CPU Unit Operation Manual Revised May 2006...
Страница 3: ...iv...
Страница 11: ...xii TABLE OF CONTENTS...
Страница 15: ...xvi...
Страница 19: ...xx...
Страница 31: ...xxxii Conformance to EC Directives 6...
Страница 71: ...40 Function Blocks Section 1 5...
Страница 133: ...102 Computing the Cycle Time Section 2 7...
Страница 169: ...138 CPM1A Expansion I O Unit Wiring Section 3 6...
Страница 411: ...380 Clock Section 6 8...
Страница 519: ...488 Replacing User serviceable Parts Section 10 2...
Страница 527: ...496 Standard Models Appendix A...
Страница 535: ...504 Dimensions Diagrams Appendix B...
Страница 628: ...597 Connections to Serial Communications Option Boards Appendix F Connecting to Unit...
Страница 629: ...598 Connections to Serial Communications Option Boards Appendix F...
Страница 659: ...628 PLC Setup Appendix G...
Страница 665: ...634 Index work words 159 write protection 370...
Страница 667: ...636 Revision History...