SCCT User Manual
Contents
1. 16 FIGURE 11 SENDING ALERT TO A SPECIFIC SUBSCRIBER WITH SENDALERT VI 16 FIGURE 1 MANAGING RECEIVED USER COMMANDS EXAMPLE 17 FIGURE 12 USE READ ACTIVESUBSCRIBERSCOUNT VI TO CHECK THE COUNT OF ACTIVE CONNECTIONS 18 FIGURE 13 USE READ ACTIVESUBSCRIBERSADDRESSES TO GET INFO ABOUT ACTIVE SUBSCRIBERS 18 FIGURE 14 USE PROPERTY NODES TO GET INFORMATION ABOUT ACTIVE 50 5 5 18 FIGURE 15 CHANGING THE WAY DIGITAL DATA ARE UPDATED TO ALL SUBSCRIBERS WITH DIGITAL PUBLISHONLYONCHANGE M ME 19 FIGURE 16 ENABLING THE REQUEST FIFO WITH ENABLEREQUESTLIST PROPERTY NODE 19 FIGURE 17 CHANGING API KEY TO AN ACTIVE PUBLISHER WITH WRITE API KEY VI 19 FIGURE 18 CHANGING API KEY TO AN ACTIVE PUBLISHER USING API KEY PROPERTY NODE 19 TOOLS for SMART MINDS 5 Smartphone amp Cross platform Communication Toolkit User Manual About this Manual The Smartphone amp Cross platform Communication Toolkit User Manual describes the virtual instruments VIs used to communicate and pass data between Labview and either a local or remote application You should be familiar with the operation of LabVIEW your computer and2. Figure 1 Simple Publisher example with analog data In this example a Publisher is created with startPublisher vi that immediately creates all necessary data structures and tasks and takes care of all incoming connections Please note that configuration cluster must be filled according to the analog signals you want to transmit channelConfiguration must describe each channel of your data acquisition In the while loop your acquired data are published directly to the active subscribers If no subscribers are connected data are discarded When the loop terminates stopPublisher vi closes all active tasks and flushes FIFO with user requests Notice startPublisher vi create some background tasks which handle the data transfer to and from active subscribers These tasks are also responsible of checking if connections are lost in case your application is not publishing any information All these tasks periodically check if your top level VI is running and stop automatically when your top level VI stops Publishing digital data In this example a Publisher is created with startPublisher vi that immediately create all necessary data structures and tasks and takes care of all incoming connections Please note that configuration cluster must be filled according to the digital lines you want to transmit digitalLines Configuration must describes each line of your data acquisition TOOLS for SMART MINDS 10 Smartphone a
3. Destroys a subscriber and close connection if active Read alert Reads next available alert received from Publisher Read analogData data transmission you must use transferStatus vi Reads next available analog data packet received from Publisher To activate Read digitalData data transmission you must use transferStatus vi Reads next available digital data packet received from Publisher To activate discardData Throws all received alerts analog and digital data and configuration clusters away transferStatus Set the status of transmission If you connect TRUE publisher start sending analog data and digital lines as soon as they are available on server side If you connect FALSE Publisher stop data transmission Alerts from publisher cannot be stopped To implement the subscriber in your application and receive data from a source you must know three parameters e Data source address that is usually the IP address of the machine where Publisher is running on e Data source port that is the TCP port of the Publisher TOOLS for SMART MINDS 11 Smartphone amp Cross platform Communication Toolkit User Manual After Publisher sends the most recent data it has so that subscriber can update svstem status API Key is the key necessary to be authenticated by publisher If a subscriber uses a wrong API Key connection is refused by publisher When your application succeeds to connec
4. addresses To know the addresses of active subscribers use Read activeSubscribersAddresses vi that returns a string array every string is a subscribers address in the form ipAddress port the array is ordered by connection time so the first element of the array is related to the active subscribers that connected first Closed connections don t appear in the array activeSubscribers Figure 13 Use Read activeSubscribersAddresses to get info about active subscribers You can use activeSubscriberCount property node to get active connection count and activeSubscriberAddress property node to get active connection addresses as shown in the following figure Publisher vdass activeSubscribersCount jactiveSubscribersAddress activeSubscribersCount 0132 activeSubscribersAddress Figure 14 Use property nodes to get information about active subscribers Publishing digital lines on change only Digital lines often don t change often so you can publish them only when they change Doing so you can reduce the consumed band on your communication channel To change the publisher works with your digital lines use the Digital publishOnlyOnChange property node If you want to publish digital lines also if they aren t changed set FALSE value to this property node If you want to publish TOOLS for SMART MINDS 18 Smartphone amp Cross platform Communication Toolkit User Manual di
5. want to publish and 1 to many applications subscribers which subscribe the service To subscribe the service and receive fresh data from the publisher they must use an API KEY to be authenticated The following figure represents the pattern Internet Intranet Subscriber N When an application wants to receive data asks the publisher to be inscribed among the active subscribers Publisher will accept all incoming requests with the valid API KEY When a application doesn t want to receive data anymore simply inform the publisher If the communication channel between publisher and subscriber fails subscriber automatically remove the subscribers from its list of active listeners Your application Publisher TOOLS for SMART MINDS 8 Smartphone amp Cross platform Communication Toolkit User Manual Using the Smartphone amp Cross platform Communication Toolkit This Toolkit is composed of two classes Publisher that creates the server side of your communication system and the subscriber that implements the client side Publisher and Subscriber work together to pass data from one application which holds the data to many applications on different systems MS Windows OS family Linux Apple systems mobile devices etc Publisher uses a platform independent data format to transmit your data so that all subscribers can read them Doing so you add a little overhead to a simple transmission that uses binary data format but ga
6. your computer operating system Conventions The following conventions appear in this manual The symbol leads you through nested menu items and dialog box options to a final action The sequence Tools Options directs you to pull down the Tools menu select Options item Bold Bold text denotes items that you must select or click on the software such as menu items and dialog box options Bold text also denotes parameter names italic Italic text denotes variables emphasis a cross reference or an introduction to a key concept This font also denotes text that is a placeholder for a word or value that you must supply monospace Text in this font denotes text or characters that you should enter from the keyboard sections of code programming examples and syntax examples This font is also used for the proper names of disk drives paths directories programs subprograms subroutines device names functions operations variables filenames and extensions and code excerpts monospace italic Italic text in this font denotes text that is a placeholder for a word or value that you must supply TOOLS for SMART MINDS 6 Smartphone amp Cross platform Communication Toolkit User Manual Introduction This chapter describes the installation procedure installed components and the main features of the Smartphone amp Cross platform Communication Toolkit Overview The Smartphone amp Cross platform Communication Toolkit
7. NDS 4 Smartphone amp Cross platform Communication Toolkit User Manual NN Q U 5 N HR HB o errr eerk rre tO OO OO OO N e FIGURE 1 SIMPLE PUBLISHER EXAMPLE WITH ANALOG 10 FIGURE 2 SIMPLE PUBLISHER EXAMPLE WITH DIGITAL DATA 211 FIGURE 3 SIMPLE SUBSCRIBER EXAMPLE THAT READS ANALOG DATA ONLY 12 FIGURE 4 TRANSFERSTATUS VI DETERMINES THE FLOW OF PACKETS BETWEEN PUBLISHER AND SUBSCRIBER 12 FIGURE 5 SIMPLE SUBSCRIBER EXAMPLE THAT READS DIGITAL DATA ONLY enne 13 FIGURE 6 SIMPLE SUBSCRIBER THAT READS CONFIGURATION CLUSTER BEFORE READING ANALOG DATA 13 FIGURE 7 USERCOMMAND VI EXAMPLE nua sees erit eese aco Fe eene ne evo pate p eap edere bu eae ees 14 FIGURE 8 READING AN ALERT FROM 5 sre nente 14 FIGURE 9 USING PROPERTIES NODES CHECK CONNECTION 5 5 2 0 210 15 FIGURE 10 USING AVAILABLE REQUEST PROPERTY NODE TO CHECK IS SUBSCRIBER S REQUESTS ARE
8. OOLS for SMART MINDS 13 Smartphone amp Cross platform Communication Toolkit User Manual Sending Commands Subscribers can send textual commands to the Publisher with userCommand vi In this context user means your application and a command is a string message that Publisher receives and pass directly to its main application The following figure illustrates the path of user commands Client application Server application User commands are sent immediately to publisher and server processes them in the same order they are received If string is empty command is not posted You can specify an additional numeric code if your application uses numeric codes to identify command sets myCommand USER Figure 7 userCommand vi example Receiving Alerts Subscribers can receive textual alerts from the Publisher with Read alert vi an alert is a cluster composed by a timestamp a string message and a numeric code The following figure illustrates the path of alerts Client application Server application Alerts are received and enqueued in a dedicated FIFO Your application have to process incoming alerts and take care of FIFO size You can use EAE Figure 8 Heading an alert from Publisher TOOLS for SMART MINDS 14 Smartphone amp Cross platform Communication Toolkit User Manual How to check the state of your connection You can monitor connection state with connected propert
9. Smartphone amp Cross platform Communication Toolkit User Manual Release 1 0 1 June 2011 Edition ToolsForSmartMinds Worldwide technical support and product information www toolsforsmartminds com TOOLS for SMART MINDS Corporate headquarter Via Padania 16 Castel Mella 25030 Brescia Italy Copyright 2010 Tools for smart minds All rights reserved TOOLS for SMART MINDS 2 Smartphone amp Cross platform Communication Toolkit User Manual TOOLS for SMART MINDS 3 Smartphone amp Cross platform Communication Toolkit User Manual Contents FIGURE INDEX ABOUT THIS MANUAL CONVENTIONS INTRODUCTION OVERVIEW INSTALLING THE SMARTPHONE amp CROSS PLATFORM COMMUNICATION TOOLKIT GETTING STARTED WITH THE SMARTPHONE amp CROSS PLATFORM COMMUNICATION TOOLKIT COMMUNICATION CONCEPTS USING THE SMARTPHONE amp CROSS PLATFORM COMMUNICATION TOOLKIT PUBLISHER CLASS CREATING A PUBLISHER PUBLISHING ANALOG DATA PUBLISHING DIGITAL DATA SUBSCRIBER CLASS CREATING A SUBSCRIBER SENDING COMMANDS RECEIVING ALERTS HOW TO CHECK THE STATE OF YOUR CONNECTION CREATING AND MANAGING ALERTS AND USER REQUESTS OVERVIEW READING AVAILABLE REQUESTS SENDING ALERTS TO A SPECIFIC SUBSCRIBER MANAGING USER REQUESTS ADVANCED OPTIONS CONTROLLING ACTIVE CONNECTIONS READING ACTIVE CONNECTION COUNT READING ACTIVE CONNECTION ADDRESSES PUBLISHING DIGITAL LINES ON CHANGE ONLY CHANGING API KEY AT RUN TIME INDEX TOOLS for SMART MI
10. erty node to retrieve the number of received request that your application has to process When a request is processed with getRequest vi availableRequests is decremented by 1 n Publisher lvclass BE availableRequests gt availableRequests Figure 10 Using available request property node to check is subscriber s requests are present Sending alerts to a specific subscriber Your application can communicate with active subscribers with custom messages called Alerts To send an Alert use sendAlert vi as shown in the following figure ipAddress port Figure 11 Sending alert to a specific subscriber with sendAlert vi Codes between 1 and 9 are reserved to publisher and your application must use code 0 default or code values higher than 9 Use message string to add additional information to your alert To send an alert to every active subscriber ipAddress port TOOLS for SMART MINDS 16 Smartphone amp Cross platform Communication Toolkit User Manual must be empty string instead if you want to send a message to a specific subscriber connect ipAddress port to the specific address and port of its connection Managing User Requests User request i e user command is inserted into a FIFO by Publisher so your application can process al request in the order they are received from Publisher The E handle user request here time address port data M Figure 1 Managing received user c
11. gital lines only when their value is different form the previous one you published set this property value to TRUE By default Publisher works with Digital publishOnlyOnChange equal to FALSE Publisher Ivclass PDigital publishOnlyOnChange Digital publishOnlyOnChange HEN UPS i Figure 15 Changing the way digital data are updated to all subscribers with Digital publishOnlyOnchange property node If your application doesn t need to handle user request you can disable userRequest FIFO to avoid waste of memory To disable or enable FIFO use enableRequestList property node as shown in the next figure Publisher lvclass enableRequestList Figure 16 Enabling the request FIFO with enableRequestList property node By default every Publisher starts with FIFO enabled so remember to consume elements in this FIFO with getRequest vi or disable the FIFO with enableRequestList property node Many properties can be set either by specific Vis or by properties nodes We encourage you to use properties node whenever it is possible Changing API Key at run time Publishers are created with API Key they use to authenticate every incoming connection You can modify the API Key at run time so that new subscribers have to use the new API Key to be accepted Existing connections are not affected by API Key changes To update the API Key use Write API Key vi as show in the foll
12. handles communication with subscribers as a set of peer to peer connections and every data you publish is transmitted individually to each subscriber So you have to identify the right size of your data streams to avoid band saturation over your communication channel Installing the Smartphone amp Cross platform Communication Toolkit Smartphone amp Cross platform Communication Toolkit is shipped as VI Package Manager Before installing Smartphone amp Cross platform Communication Toolkit you must install a copy of VI Package Manager on your machine You can download a free copy of VIPM at this address TOOLS for SMART MINDS 7 Smartphone amp Cross platform Communication Toolkit User Manual http www jki net viom download To install Smartphone amp Cross platform Communication Toolkit double click on smartphone amp crossplatform communication toolkit 1 x x xx vip and follow the installation wizard Package contains LabVIEW Vis as well as documents in PDF format installed c SCCT Manuals and libraries to create applications with Java Android and Net in c SCCT cross platform libs Getting started with the Smartphone amp Cross platform Communication Toolkit Communication concepts Smartphone amp Cross platform Communication Toolkit implements the publisher subscriber pattern This well known pattern is also called Observer pattern In this pattern you have one application publisher that receives the data you
13. in a great portability and opportunity to communicate with heterogeneous systems To better understand the way this communication works think to this example A publishing company receives requests from different subscribers who want to receive a magazine As long as they are subscribed they receive the magazine When they don t want to receive it anymore simply cancel their subscription Your application can implement more than one Publisher each of them works on different port of your machine An application can contain publishers and subscribers together working with different remote machines at the same time Either objects work in background of your application with specific tasks that are created and destroyed automatically Publisher Class Publisher is a Class with methods and properties detailed in the following tables Publisher Class Property name description Read write availableRequests gets the count of received requests from subscribers Read only enableRequestList Sets gets the management of subscriber requests Read Write Port Gets the actual port number Read only API Key Gets the actual API Key Read Write activeSubscribersCount Gets the count of active connections Read only activeSubscribersAddresses Gets the IP address and port of each active connection Read only Digital publishOnlyOnChange Sets gets the property that define digital lines are Read Write published if true digital lines are t
14. is an add on package for communicating data trough applications The toolkit contains a set of high level functions for sending your application data and advanced functions for customized tasks The following list describes the main features of the Smartphone amp Cross platform Communication Toolkit e Works over any TCP IP connection Works over Local Area Networks as well as Internet connections Implements the publisher subscriber pattern also know as Observer pattern Authenticate subscribers through a API KEY Controls in background the state of every connection to identify loss of communication Publishes GPS coordinates to manage mobile systems e Works with platform independent Data format and communicate with multiple platforms at the same time third party vendors have implemented toolkit to develop on Android platform Java NET and VB Because of the wide range of devices the Smartphone amp Cross platform Communication Toolkit works with some portability issues remain Consider the following issues when choosing your way to publish data e Some smart phones and tables uses CPU with low computing power so are not able to receive and process large streams of data e Smartphone amp Cross platform Communication Toolkit uses a platform independent data format and subscribers require a some computing power to decode data streams into their specific binary format e Smartphone amp Cross platform Communication Toolkit
15. lkit User Manual To get analog data use Read analogData vi that returns a packet of data Background tasks takes care of all received packets and enqueues them in a FIFO so you can process all packets without data loss To know the number of available packet use the property node that returns the data packets count The following figure illustrate the case of reading digital lines only Notice that at the end of the while loop you always have to close communication with publisher When communication is closed if you want to open again the communication use openCommunication vi digitalLines localhost Sesesscen code aS z p digitalLines abc 127 Figure 5 Simple subscriber example that reads digital data only Publisher automatically sends a communication cluster that describes the remote System Use this cluster to properly format your graph and chart setting x and y scales as shown in the following figure Estes Fg 50 eej fo TT o9 gt stop Figure 6 Simple Subscriber that reads configuration cluster before reading analog data Notice openCommunication vi create a background task which handles the data transfer to and from the publisher This task is also responsible of checking connection is lost in case publisher is not sending any information This task periodically checks if your top level VI is running and stops automatically when your top level VI stops T
16. mp Cross platform Communication Toolkit User Manual In the while loop your acquired data are published directly to the active subscribers If no subscribers are connected data are discarded When the loop terminates stopPublisher vi closes all active tasks and flushes FIFO with user requests Configuration Figure 2 Simple publisher example with digital data Subscriber Class Subscriber is a Class with methods and properties detailed in the following tables Subscriber Class availableAlerts Gets the number of received alerts from Publisher that Read only application has to process availableAnalogData Gets the number of analog data packets received from Read only Publisher that application has to process availableConfiguration Gets the number of configuration clusters received from Read only publisher that application has to process Remember that when you establish a connection you receive immediately a configuration cluster availableDigitalData Gets the number of digital data packets received from Publisher Read only that application has to process connected Returns TRUE if connection is active FALSE if connection is Read only lost connectionStatus Gets a numeric code related to connection status Read only Subscriber Class method name description openConnection Creates a subscriber and open a connection with a running Publisher closeConnection
17. ommands example First you have to check that found indicator is TRUE if found is FALSE no request is available All requests are classified with event field User requests are returned with user command received value as shown above Every request has its time field address port field that identify the subscriber that sent the request and an optional data field Every request has an event code which helps you to identify the request class Event is a enum that can assume one of the following values TOOLS for SMART MINDS 17 Smartphone amp Cross platform Communication Toolkit User Manual Advanced Options Controlling active connections Publisher Vis handle all incoming connections and close inactive connections so you just focus on your main application and forget all issues related to data transmission In some cases you want to know the number of active connections and the address of subscribers Usually you can map all incoming connections using getRequest vi and filtering events such connection successful and connection closed and connection timeout which help you to map all active and closed connections Reading active connection count To know the count of active connections at a specific time use Read activeSubscribersCount vi that returns the number of active connections activeConnections Figure 12 Use Head activeSubscribersCount vi to check the count of active connections Reading active connection
18. owing figure Figure 17 Changing API Key to an active Publisher with Write API Key vi Alternatively you can use API Key property node as shown below eae ae t Publisher lvclass Br Figure 18 Changing API Key to an active Publisher using API Key property node TOOLS for SMART MINDS 19 Smartphone amp Cross platform Communication Toolkit User Manual Index A active connection addresses 18 CHANGING ss aiit available Requests P Publisher Methods ban teet Rd 9 sinistre re 9 Publisher Class 9 5 Subscriber methods ute iecore eto ertet d tre ege properies Subscriber Class U User Request TOOLS for SMART MINDS 20 Smartphone amp Cross platform Communication Toolkit User Manual
19. ransmitted only if their value is changed otherwise they are transmitted every time regardless of their value Publisher Class method name description PublishData Publishes analog and or digital lines startPublisher Implements a publisher object stopPublisher Destroy a Publisher object updateConfiguration Transmit a new system configuration to all active connections getRequest Get the next request from one of the active connections sendAlert Transmit a message to a specific connection or to all active connections TOOLS for SMART MINDS 9 Smartphone amp Cross platform Communication Toolkit User Manual Creating a Publisher To create a publisher in your LabVIEW application use the palette SCCT Publisher the following examples show how to create a publisher in few click To create a publisher in your application you must choose two parameters that have to shared with subscribers e Publisher port is the TCP port that Publisher uses to manage all TCP connections e API Key is the connection password that subscribers must communicate to publisher to be authenticated Take care to use one of the available port of your machine Some ports are reserved for other common applications like port 21 to FTP 80 to HTTP and so on Moreover you have to check that the chosen port is open on your company firewall Publishing analog data Configuration a DAQ Assistant data
20. t publisher sends immediately a configuration of remote system i e analog channel descriptions unit of measure and range of all signals digital line descriptions and system location GPS coordinates Creating a Subscriber In the following example you create a simple subcriber with openConnection vi that need three parameters Publisher address default value is localhost Publisher port default value in 8081 and API Key pe gt abc stop Figure 3 Simple Subscriber Example that reads analog data only Publisher doesn t start data transmission automatically After connection your subscriber must tell to the Publisher to start sending data If your subscriber doesn t need fresh data use transferStatus vi with a FALSE constant to tell to publisher to stop sending data To re start data transmission use transferStatus vi with TRUE constant Publisher doesn t buffer data if transmission is stopped The following diagram illustrates how analog and digital data are managed in situation YOUR APPLICATION PUBLISHER SIDE When transferStatus FALSE publisher doesn t send fresh data to subscriber These data are discarded connection P a i SUBSCRIBER SIDE Connection start here transferStatus FALSE transferStatus TRUE Figure 4 transferStatus vi determines the flow of packets between publisher and subscriber TOOLS for SMART MINDS 12 Smartphone amp Cross platform Communication Too
21. y node which returns TRUE if your connection is still alive A connection is alive also if Publisher is not sending data to your subscriber Publisher and subscriber exchange acknowledge packets to verify if connection is still active so you don t have to eee Subscriber Ivclass Figure 9 Using properties nodes to check connection status TOOLS for SMART MINDS 15 Smartphone amp Cross platform Communication Toolkit User Manual Creating and managing alerts and user requests Overview When an active communication is established between Publisher and subscriber they can exchange some messages with a specific format messages from your application to subscriber s are called Alerts Every alert is composed by a numeric code and a message string Messages from subscribers to your application are called user requests Every user request contains a numeric code a timestamp a connection identifier an event code and an optional data string Publisher uses a FIFO to enqueue all incoming user requests in the order they are received Your application can identify which subscriber is sending the request by its ipAddress port identifier Reading available Requests Subscribers send their request to your application and Publisher keeps them in a FIFO together with some messages it sends to inform your application about the connection status and the communication between publisher and subscribers Use availableRequests prop
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