Overview; Socket Service Functions - Omron CJ1W-ETN11 Operation Manual

Overview

6-1

Overview

6-1-1

Socket Service Functions

Using Socket Service Request Switches
Using CMND(490)
104
The socket services allow devices on the Ethernet to send and receive vari-
ous data using the UDP or TCP protocol. The socket services can be used by
CS/CJ-series PCs through the user program by manipulating dedicated bits
(called Socket Service Request Switches) or by executing the CMND(490)
instruction.
The two methods of using the socket services are as follows:
• Dedicated Bits (Socket Service Request Switches)
Requests can be made to a socket service by setting parameters and
then merely manipulating specific Socket Service Request Switches.
• CMND(490)
Requests can be made to a socket service by sending service request
commands to the Ethernet Unit.
Note One of the main differences between using Socket Service Request Switches
and using CMND(490) is in the number of sockets that can be connected
simultaneously, as shown in the following table.
Protocol
UDP
TCP
CS/CJ-series PC
CPU Unit
Socket Service
Request Switches
Socket Service
Parameters
(See note 2.)
Note 1. Socket Service Request Switches in the CPU Bus Area in the CIO Area
are used to send a service request from the CPU Unit to the Ethernet Unit.
2. The Socket Service Parameters in the CPU Bus Unit Area in the DM Area
are used to specify the service being requested from the Ethernet Unit.
The CPU Bus Unit Area in the DM Area is also used to receive results of
processing from the Ethernet Unit to the CPU Unit.
CS/CJ-series PC
CPU Unit
FINS response
Socket Service Request
Switches
Total of 8 sockets max.
Ethernet Unit
Refreshed
(See note 1.)
Refreshed
Ethernet Unit
FINS
TCP data
command
transfers
UDP data
transfers
Processing
results
CMND(490)
8 sockets max.
8 sockets max.
Host computer
or other device
TCP data
transfers
System
call
UDP data
transfers
Host computer or other device
User program
System
call
Section 6-1
User program