extending labview to the web using “labsockets”

Extending LabVIEW tothe Web using the

LabSocket System

John BergmansBergmans Mechatronics LLC

www.bergmans.com

National Instruments LabVIEW User Group MeetingSanta Ana, CANov 17 2010

1616 Bedford Lane, Unit A Phone: 714-474-8956Newport Beach, CA 92660 Fax: 949-646-1429

B e r g m a n s M e c h a t r o n i c s L L C

Goal: monitor and control a LabVIEW application using a plug-in-free browser

Potential Use-Cases

Monitor and control a LabVIEW-controlled lab test from the desktop in office or on the road using a mobile device

Monitor large-scale LabVIEW application by crews in the field ie oil rig equipment monitoring

For low-cost embedded systems eliminate physical UI by using browser to interface to device

Bergmans Mechatronics LLC

Remote Access to LabVIEW Application

LabVIEW Application

Browser onLaptop,

Desktop orMobile DeviceDesktop /

Embedded Device

1. Native Client App Use TCP/IP sockets, LabVIEW shared variables, or .NET, to transmit

data between client and LabVIEW Requires custom client development and modifications to LabVIEW app

2. LabVIEW Remote Panels Requires LabVIEW Run-Time Engine (RTE) and browser plug-in

3. LabVIEW Web Services Data transferred between application and client using the HTTP request-

response model (REpresentative State Transfer (REST) architecture) Requires development of client software using Web languages

eg. HTML/JavaScript

4. LabVIEW Web UI Builder (http://www.ni.com/uibuilder/) Build and run apps in browser using reduced-capabiliy LabVIEW Requires Silverlight plug-in (runs on Windows and Mac OS X)


Current Approaches


Browser/Back-End Communications

Traditional interface between browser and web server

Desktop Server

1) Data Request

2) ReplyBack-End

ApplicationBrowserWeb Server

Software


Traditional interface between browser and web server

Desktop Server

1) Data Request

2) ReplyBack-End

ApplicationBrowserWeb Server

Software

Continuous bi-directional communication between browser and server using WebSocket

Desktop Server

WebSocketServer

Back-EndApplication

WebSocket

Browser

Data to Back-End App

Data from Back-End App

Browser/Back-End Communications


WebSocket

Enables continuous, bidirectional communications between browser and server

Originally part of new HTML5 specification, now a stand-alone spec (W3C API, IETF protocol)

Simple browser and back-end implementation

Substantially reduced header info size (request and response: ~900 bytes vs WebSocket: 4 bytes)

Multiple organizations developing WebSocket servers

Kaazing Corp., Mountain View, CA (www.kaazing.com) Developer of commercial WebSocket gateway Emulation for legacy and mobile browsers Contributor to HTML5 spec Disclosure: BML has referral agreement with Kaazing


Sample BML Demo Applications using WebSocket

Interface to MySQLhttp://http://www.bergmans.com/lab/ws_sql.html

EarthControl Multiplayer Facebook gamehttp://apps.facebook.com/earthcontrol


LabSocket = LabVIEW + WebSocket

LabSocket system uses WebSockets to enable automatic replication of LabVIEW front panel in a browser without plug-ins

Data transfer via

WebSocket

Data transfer via

TCP/IP Socket

LabVIEW Application

WebSocketGateway

MessageBroker

LabSocketInterface

Browser onDesktop or

Mobile DeviceDesktop / Embedded Device

Server


LabSocket = LabVIEW + WebSocket

LabSocket system uses WebSockets to enable automatic replication of LabVIEW front panel in a browser without plug-ins

Data transfer via

WebSocket

Data transfer via

TCP/IP Socket

LabVIEW Application

WebSocketGateway

MessageBroker

LabSocketInterface



LabSocket Interface

Startup- Establish TCP/IP socket connection to message broker- LabVIEW Front Panel Screen Scrape, send JavaScript code to web server

Steady-state- Transmit updates in LabVIEW front panel to browser- Update LabVIEW front panel based on events generated in browser

Server

Asynchronous MessagingProtocol

Data transfer via WebSocket

Data transfer via TCP/IP Socket

LabVIEW Application

CloudServer WebSocket

GatewayMessage Broker

LabSocketInterface


LabSocket Cloud Service Configuration




Demohttp://www.bergmans.com/lab/LabSocket.html

LabVIEW Front Panel Chrome Browser


Screenscrape SubVI

Label for one LED


Future Work Perform demo / proof-of-concept testing

Complete cloud service Allow LabVIEW developers to automatically set up applications Subscription set up

Improved GUI element support Additional GUI elements Additional GUI element properties (color, font type, etc)

extending labview to the web using “labsockets”

Documents