92
About Data Read/Write Services
Section 6-1
6-1
About Data Read/Write Services
A SYSMAC LINK Unit provides read/write services that can be used to trans-
fer data and control other nodes on the network or interconnected networks.
The data read/write services use a command/response format. Each time that
data or a command from a host computer or CS-series PLC is transmitted, the
receiving node returns a response. If responses are not needed, the Unit can
be set so that responses are not returned. The same transmission can also
be broadcast simultaneously to all nodes on the network.
Data Read/Write Service Transmissions
The data read/write services with the SYSMAC LINK Unit can be divided into
four processes, as described below.
Computer-originating
Commands
A program is prepared in the computer that transmits commands and receives
responses. (When programming in the C code, commands can be transmitted
with
slksend
and responses received with
slkrecv
or
slkrcvw
.)
PLC-originating Transfers
Data is transmitted from the PLC using the SEND(90), RECV(98), and
CMND(490) instructions. You may need to move data being transferred to/
from the locations in memory specified in the instruction, but the actual trans-
mission and reception is handled automatically.
Computer Responses
A program that returns proper responses for received commands must be
prepared and loaded in the computer prior to command reception.
PLC Responses
The SYSMAC LINK Unit receives and processes commands and returns the
proper responses automatically. Since all of the processing is handled auto-
matically, you do not need to prepare a routine for command reception in the
PLC program.
6-2
PLC Network Instructions
Data is sent from the PLC to other nodes (PLCs or computers) using the
SEND(90), RECV(98), or CMND(490) instruction in the PLC user program.
6-2-1
Specifying Destination Nodes
The following two types of communication are possible. Messages can be
sent to or received from a specific node, or it can be broadcast to all nodes.
Sending and Receiving
Data Between Specific
Nodes
The PLC’s network instructions (SEND(90), RECV(98), and CMND(490)) can
be used to transfer data to or from a node specified by network address and
node address. The unit address is also specified, enabling communications
with a specific Unit at the specified node.
Send data
Receive data
Node 1
Node 2
Node 3
Node 4
Node 5
Summary of Contents for CS1W-SLK11-21 - 06-2004
Page 1: ...Cat No W367 E1 02 SYSMAC CS1W SLK11 21 SYSMAC LINK Units...
Page 2: ...CS1W SLK11 21 SYSMAC LINK Units Operation Manual Revised June 2004...
Page 3: ...iv...
Page 5: ...vi...
Page 9: ......
Page 11: ......
Page 17: ......
Page 49: ......
Page 107: ......
Page 139: ...122 FINS Commands for SYSMAC LINK Units Section 6 4...
Page 143: ......
Page 170: ...153 Appendix B Dimensions CS1W SLK11 Optical SYSMAC LINK Unit Unit mm...
Page 171: ...154 Dimensions Appendix B CS1W SLK21 Coaxial SYSMAC LINK Unit Unit mm...
Page 177: ......
Page 179: ......
Page 195: ......
Page 199: ......
Page 202: ...SYSMAC CS1W SLK11 21 SYSMAC LINK Units Cat No W367 E1 02 OPERATION MANUAL...