Passive Open and Active Open | Omron CJ1W-ETN21 manual

Protocol Overview

Section 6-2

■Passive OPEN and Active OPEN

Client

TCP socket

An open command is executed for a node to establish a connection. The open method differs depending on whether the node is a client or server. A passive open method is used to open the node as a server and the active open method is used to open the node as a client.

Active	Passive
open	open	Server
		Server
		TCP
		socket
	Connection

Note 1. TCP sockets must be closed once a connection has been made before communications are possible with other TCP sockets. This is true for other server and client sockets. Up to eight TCP sockets can be open simulta- neously.

2.With UDP sockets, communications are possible with more than one other UDP socket.

3.When a connection is made between two nodes, the process at the node providing a service is called the server, and the process at the node re- questing the service is called the client. The server is started first and waits for a service request from a client. The client requests to the server that a connection be opened and then transmits data. When the TCP protocol is used, however, the client–server relationship does not need to be pro- grammed in the application because it is automatically handled by the pro- tocol.

TCP Communications Procedure

The communications procedure is shown below for communications between a host computer and Ethernet Unit using a TCP socket. In this example, the host computer is the server and the Ethernet Unit is the client.

Host computer (server)

Passive open

Connection requested

Connection established

	Send data
Data receive request	ACK (acknowledge)
Data receive request
Data send request	Send data
	Send data
Next data receive request	ACK (acknowledge)
Next data receive request

Ethernet Unit (client)

Active open

Connection established

Data send request

Send next data

Data receive request

Close

Close

101

Image 125

Omron CJ1W-ETN21 operation manual Passive Open and Active Open, TCP Communications Procedure

Contents

Ethernet Units Construction of Applications Revised November  Omron Omron Product ReferencesPage Table of Contents FTP Server Index 207 Revision History 215 Table of Contents Information on how to manage and use IP addresses Information on setting communications using CX-ProgrammerCommands Section Contents Relevant Manuals Manual Model Name Contents Number Xiii Xiv Read and Understand this Manual Application Considerations Disclaimers Xviii Confirming Unit Versions with Support Software Unit VersionsNotation of Unit Versions on Products Lowing table Unit Version Notation Precautions Intended Audience General PrecautionsSafety Precautions Safety Precautions Application Precautions Operating Environment Precautions Application Precautions Applicable Directives Conformance to EC DirectivesConcepts EMC Directives Section Service Main functions Counterpart device Reference Ethernet Unit Communications ServicesFunctions Listed by Purpose Acquired for the Ethernet Unit Unit setting tag Communications Protocol used Situation when used ReferenceTable of Protocols Section Smtp Common Protocol SettingsContents Default 2 POP 3 DNS Section Section Mail Send Function Introduction Mail Send Function OverviewAdvantages Description Mail Send Functions Compatibility with Earlier Models Mail Send Function DetailsComparison with the Earlier Mail Send Function Contents of E-mail Body Trigger condition Text entered as subject Following header information is included Ethernet Unit Information Words value has changed Channel data has changed from XX toEthernet Unit information is always included in the e-mail Optional Information Extension Content Error Log Information Status InformationAttached File Details Memory Data 6,000 Words Max Data sent Body/Attached file Mail body Summary of E-mail Body Information and Attached FilesFile Data 1 MB Max Specifications Mail Send Function SpecificationsFunction Specifications Procedure Using the Mail Send FunctionDetails of the Available Mail Triggers Classification Trigger type Transferring the settings data Settings Required for the Mail Send FunctionSetting Setting requirement Reference Unit Setup Using the Mail Send Function Send Mail Set up to 2 destination mail addressesMail Address Mail Address Specification Required Send Mail Condition SettingsData Sent by Mail When Required Data Sent in E-mail Body Data Sent in an Attached File Attached File Name Send Mail Trigger Type Setting Required Send Mail Status Mail Send Function StatusSend Mail Status Bit numbers Status Mail Send Switch, Accessing Memory/Sending Mail FlagMail Send Switch Bit 03 of n Memory Data Formats Accessing Memory/Sending Mail Flag Bit 01 of n+17IOM Format TXT Format CSV Format Attached File Transfer Times Identifying and Correcting Mail Send Function Errors Mail Send Function ErrorsAccess Times for CS1 and CJ1 CPU Units Access Times for CS1-H and CJ1-H CPU Units Error Log Error Codes for the Mail Send Function Troubleshooting Mail Send Errors with LED IndicatorsError Meaning Detailed error code Correction Probable cause Correction Initial Settings Example Make the Unit Setup Settings from the CX-ProgrammerInitial Server Settings Example Application Send Condition Setting Destination Mail Address Setup Automatic Transmission when Send Condition is Satisfied Transfer the CPU Bus Unit Setup SettingsExample Send e-mail when W300 bit 00 goes from OFF to on Send when there is a Change in the CPU Units Status Receive Mail Function Mail Receive Function Overview Configuration of the MailAdvantages Description Command Parameters Table of Remote Mail CommandsCommand Execution Results Attached File Data Received E-mail Mail Receive Function SpecificationsSpecification Response E-mail Using the Mail Receive Function Tion Settings Required for the Mail Receive Function Receive Mail Tab Posting Mail Address Protection Setting Receive Command Setting Receive Attached File Setting Command Format Remote Mail Command DetailsFormat Response Format FileWrite File Write Command FormatFunction Mounted in the CPU Unit FileRead File Read Card mounted in the CPU Unit FileDelete File Delete Response Format Details FileList File List ReadEM file memory or a Memory Card mounted in the CPU Unit Memory or a Memory Card mounted in the CPU Unit UMBackup User Memory BackupCommand Format Details Or a Memory Card mounted in the CPU Unit PARAMBackup Parameter Area Backup Units I/O memory. The data is written in word units IOMWrite I/O Memory Write Subject Body Units IOMRead I/O Memory Read ReIOMRead Changes the CPU Units operating mode ChangeMode Operating Mode Change Bus Unit or Special I/O Unit ErrorLogRead Error Log Read ErrorLogClear Error Log Clear MailLogRead Mail Log Read Since power was turned on or the mail log was cleared Net Unit MailLogClear Mail Log Clear Test Mail Test Response Response Status Description Code FinsSend Fins Command SendResponse List Accessing Memory/ Receiving Mail Flag Bit 02 of n+17 Accessing Memory/Receiving Mail FlagMail Receive Function Status IOM Format CSV Format TXT Format Access Times for CS1-H CJ1-H CPU Units Access Times for CS1 CJ1 CPU Units Troubleshooting Mail Receive Errors with LED Indicators Mail Receive Function ErrorsIdentifying and Correcting Mail Receive Function Errors Hex 1st byte 2nd byte Error code Meaning Detailed error code Correction Item name Example DNS Server IP Address Setting DNS Tab, When RequiredInitial Settings for the Mail Receive Function Backing Up the CPU Units User Program Memory Card Send Remote Mail CommandsReading Data from a CPU Unit Data Area FTP Server Overview Specifications File Types Connecting to the FTP ServerFTP Server Function Details FTP File Transfer Mode Using the FTP Server Function Setup Tab List of Settings Required for the FTP Server FunctionCX-Programmer Settings Setting conditions Tab Setting Details Default value Confidential FTP Server Application Example Table of Commands Using FTP CommandsUsing the Commands Open Rename UserDir Rmdir MkdirPwd Cdup Get TypeMget Put Mdelete DeleteClose Bye Message Meaning Error Messages and FTP StatusError Messages FTP indicator Meaning FTP IndicatorChecking FTP Status FTP Status Flag File Memory Using File MemoryFile Names Directories Unit File type File name Extension Contents DescriptionFile Names Handled by CPU Unit 4 I/O Memory Data Format Initializing File MemoryMemory Initialization method Data format Use of CRs and CR position Section 9ABC CS1 CPU Units/CJ1 CPU Units FTP File Transfer TimeCS1-H CPU Units/CJ1-H CPU Units File system Memory Card EM File Memory Unix Application Example Enter the login name Change data type to binary Change to the Memcard directoryTransfer the file RESULT.IOM to the workstation Write the file PLAN.IOM to the Memory Card Section Automatic Clock Adjustment Function CPU Unit Conditions Overview Using the Automatic Clock Adjustment Function Settings Setting conditions Reference Settings Required for Automatic Clock Adjustment Function Auto Adjust Time Automatic Clock Adjustment Error Processing Automatic Clock Adjustment SwitchAutomatic Clock Adjustment Sntp Errors Automatic Clock Adjustment Switch Bit 04 of n Automatic Clock Adjustment Error Processing CPU Unit error Socket Services Page Overview of Socket Communications from Ethernet Units Using Sockets with the Ethernet UnitWhat are Sockets? Socket Port Numbers Differences between TCP and UDP Protocol OverviewOpening TCP Sockets TCP Communications Passive Open and Active Open TCP Communications Procedure Fragmentation of Send Data Socket Service Functions Protocol Socket Service Request CMND490 Using Socket Services with Socket Service Request Switches Specific Socket Service Functions Using Socket Services with CMND490Command code Name Protocol Socket service request Differences with Previous Models Socket Service Function GuideManipulating Dedicated Control Bits Executing CMND490 Settings Required for Socket Service Function Using Socket Service FunctionsCX-Programmer Setting Setting requirements Unit Setup Tab Manipulating Dedicated Control Bits Details Default value Setup 109 UDP/TCP Socket Status Ethernet Unit to CPU Unit Socket Service StatusCIO Area Allocations DM Area Allocations Bit Switch Status Manipulated Unit operation Procedure Application ProcedureTCP Connection Status Ethernet Unit to CPU Unit Number Status Meaning Precautions Socket Services and Socket Status Program Flow Error Evaluation Socket Service Parameters Use of the parameters by the socket service Parameter SettingsUDP Socket Services TCP Socket Services Socket Option ParametersUDP/TCP Socket No Local UDP/TCP Port No Remote UDP/TCP Port No Following specifications can be usedTime Out Time Number of Bytes to Send/Receive Following diagram Socket Service Request Switches UDP Socket Open Request Response CodesUDP Socket Receive Request Response Meaning Code UDP Socket Close Request UDP Socket Send Request TCP Socket Active Open Request TCP Socket Passive Open Request Drinuse TCP Socket Receive Request TCP Socket Send Request TCP Socket Close Request Timing ChartsClosing during Other Processes Force-close Switch Close Request Switch 8 TCP/IP Communications Programming Example System ConfigurationData Flow Basic Operations CIO Area Program Memory MapDM Area TCP Passive Open Programming Example 130 9 UDP/IP Communications Programming Example Programming example uses the following system configuration CIO 000000 is turned on to request opening a UDP socket from Tion on errors 133 134 135 Using Socket Service Using Socket Services with CMND490 137 Command Code Basic Fins Command FormatSocket Number Results Storage Area Communications Timing Chart Response Codes in the Command ResponseSocket Service Timing Chart Response Codes in the Results Storage Areas 140 Close Request during Receive Request System Configuration Basic Operations Data Flow Are structured Program Memory Maps 144 145 146 147 148 149 150 151 152 153 154 UDP and TCP Socket Services Precautions in Using Socket ServicesUDP Socket Service TCP Socket Service Precautions in Using Socket Service Request Switches CS-H/CJ-H CPU Units Maximum Transmission Delays Ignoring other Network DelaysTCP Socket Services Using CMND490 CS/CJ CPU Units Calculation Using Fins Communications to Create Host Applications Communications On an Ethernet Network Overview of Fins Communications Fins Communications Service Specifications for Ethernet Using the FINS/UDP and FINS/TCP Methods Fins Frames Fins Command Frame FormatFins Response Frame Format Fins Header Information FINS/UDP Method FINS/UDP Features FINS/UDP FINS/UDP Frame Format UDP Port Numbers for Procedure for Using Communications Parameters Used by Host Computer Sending Commands from a Host ComputerDesignating Remote Addresses Mand, the command will be resent By sending a Fins command Memory Area READ, command codeFINS/UDP Sample Program Operation Overview 15 * FINS/UDP Communications Sample Program Sample Program 169 170 FINS/TCP Method FINS/TCP Features FINS/TCP Connection Numbers FINS/TCP Frame FormatTCP Port Number for Age them in an internal table CommunicationsFINS/TCP Connection Status Word n+23 Automatic Allocation Fins Node Addresses Automatic Allocation Procedure 175 FINS/TCP Tab Setup Tab Fins Node Address Data Send Client to Server Command FINS/TCP Mode SpecificationsFins Node Address Data Send Server to Client Command FINS/TCP Headers Error code Details Hexadecimal Fins Frame Send CommandFollowing table shows the list of error codes Command Fins Frame Send Error Notification Command Normal Operation Connection Sequence ACK FIN Error Connection Sequence 182 183 Host computer Remote node From onwards, the connection is established again FINS/TCP Sample Program 186 187 188 189 190 191 Write Command Delay Time Maximum Transmission Delays Writing/Reading to CPU UnitTransmission Delay Receive Processing Command CPU Bus Unit Service Cycle Transmission Processing Read Command Delay Time704 ms Response 194 Parameter Value Description Ethernet Network Parameters Appendix a Appendix B Buffer Configuration Network Memory Status Meaning TCP Status Transitions Appendix C Space Ascii Characters Appendix D Settings after Replacing an Ethernet Unit MaintenanceSettings After Replacing a CPU Replacing an Ethernet Unit Appendix E Tools Required for Inspection InspectionsItems Appendix F Numerics Index 209 210 211 212 213 214 Revision History Revision code Date Revised content Revision History Regional Headquarters Omron Corporation Control Devices Division H.Q Authorized Distributor