![Omron SYSMAC CJ1W-SCU21-V1 Operation Manual Download Page 41](http://html1.mh-extra.com/html/omron/sysmac-cj1w-scu21-v1/sysmac-cj1w-scu21-v1_operation-manual_743586041.webp)
12
Features
Section 1-4
Note
Serial Communications Boards send/receive data using TXD(236)/RXD(235)
instructions. Serial Communications Units send/receive data using
TXDU(256)/RXDU(255) instructions.
1-3-7
Modbus-RTU Slave Mode
Modbus-RTU slave mode enables sending Modbus-RTU commands from the
host computer to read and write PLC I/O memory.
1-4
Features
This section describes the features of the Serial Communications Boards, the
Serial Communications Unit, and the protocols.
1-4-1
Serial Communications Boards and Units
Serial Communications
Boards (CS Series Only)
A Serial Communications Board is installed as an option in a CPU Unit. Two
serial ports can thus be added without using an I/O slot.
There are two types of Serial Communications Boards: One with two RS-
232C ports and one with one RS-232C and one RS-422A/485 port. The RS-
422A/485 port can be used for a 1:N connection with general-purpose exter-
nal devices without using Link Adapters to support the protocol macro func-
tion or NT Link function.
Serial Communications
Unit (CS/CJ Series)
A total of up to 16 CPU Bus Units can be mounted on the CPU Rack or an
Expansion Rack. The total of 16 must include all Serial Communications Units
and all other CPU Bus Units. The PLC can thus be expanded to provide addi-
tional serial ports as required by the system.
1-4-2
Protocols
Host Link Communications
Host Link communications are supported by all CS/CJ-series CPU Units.
Serial Communications Boards and Units can be used to connect a single
PLC to more than one host computer for Host Link communications, including
slave-initiated communications. Host Link communications provide the follow-
ing features.
Connect One Computer to
Multiple PLCs
An RS-422A/485 port can be used to connect one host computer to up to 32
CS/CJ-series PLCs.
ST
CR+LF
Serial Communications Unit
No-protocol
Text
E.g., TXDU
E.g., Execute data transmission
General-purpose external device
Note: Start code and end code can be specified.
Modbus-RTU
Modbus command
Serial Communications Unit
Summary of Contents for SYSMAC CJ1W-SCU21-V1
Page 3: ...iv...
Page 5: ...vi...
Page 9: ...x...
Page 15: ...xvi...
Page 89: ...60 Basic Operating Procedure Section 1 9...
Page 151: ...122 RS 232C and RS 422A 485 Wiring Section 3 4...
Page 173: ...144 Host Link Function for Replacing Existing PLCs Section 4 6...
Page 223: ...194 Enhanced Protocol Macro Functions Section 5 6...
Page 277: ...248 Communications Frames Section 6 8...
Page 291: ...262 Basic Operating Procedure in No protocol Mode Section 7 4...
Page 301: ...272 Auxiliary Area and CIO Area Allocations Section 8 3...
Page 391: ...362 Introduction Appendix A...
Page 421: ...392 CompoWay F Master Protocol Appendix B...
Page 513: ...484 E5 K Digital Controller Read Protocol Appendix F...
Page 571: ...542 E5ZE Temperature Controller Write Protocol Appendix I...
Page 587: ...558 E5 J Temperature Controller Protocol Appendix J...
Page 627: ...598 ES100 Digital Controller Protocol Appendix K...
Page 661: ...632 V500 V520 Bar Code Reader Protocol Appendix M...
Page 697: ...668 3Z4L Laser Micrometer Protocol Appendix N...
Page 717: ...688 Visual Inspection System Protocol Appendix O...
Page 755: ...726 V600 V620 ID Controller Protocol Appendix P...
Page 763: ...734 Hayes Modem AT Command Protocol Appendix Q...
Page 767: ...738 Changing Communications Port Settings Using STUP 237 Appendix R...
Page 781: ...752 Revision History...