
Using Socket Services by Manipulating Dedicated Control Bits | Section |
Note The Open Flag will not turn ON at all if a
6-7-8 TCP/IP Communications Programming Example
| The following programming example illustrates transferring 100 bytes of data |
| between an Ethernet Unit and a host computer using TCP/IP communica- |
| tions. |
System Configuration | The programming example uses the following system configuration. For the |
| TCP connection, the Ethernet Unit uses a passive open and the host com- |
| puter uses an active open. |
Host computer | Ethernet Unit |
| |
| PLC |
| IP address: | 196.36.32.55 | IP address: | 196.36.32.101 |
| Port number: | 4096 | Port number: | 4096 |
Data Flow | The data will flow between the CPU Unit, Ethernet Unit, and host computer as | |||
| shown in the following diagram. |
|
|
| Line | Ethernet |
Host computer | (Ethernet) | Unit |
| Sent to line. |
|
Processing in |
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host computer |
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|
CPU Unit
Request Switches and ex- ecution bits turned ON (see note).
Execution bits turned OFF
Note Here, “execution bits” refer to CIO 000000 to CIO 000003, which are used in the ladder diagram to control execution of communications.
Basic Operations
•CIO 000000 is turned ON to request opening a TCP socket from the Ethernet Unit.
•CIO 000001 is turned ON to request closing the TCP socket from the Ethernet Unit.
•CIO 000002 is turned ON to request sending data from the Ethernet Unit. Data (100 bytes) is sent beginning at D00000.
•CIO 000003 is turned ON to request receiving data from the Ethernet Unit. The data that is received (100 bytes) is stored beginning at D01000.
•One of the bits between CIO 000100 and CIO 000103 will turn ON if an error occurs. Refer to
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