Design Overview
Digitron Instrumentation Ltd Woodland Road Torquay, Devon TQ2 7AY, United Kingdom Phone: +44 (0)1803 407865 Fax: +44 (0)1803 407699 Email: info@digitron.co.uk www.digitron.co.uk
Functional Overview
The DigiTrak-PDA application is a combination back office server / PocketPC Handheldbased application that automates a number of the manual Food Safety and Quality related data collection processes required for regulatory compliance (HACCP, JCAHO, etc.) or as part of a Quality Control program, including: • • • • • • Quality / Inspection Checklists Food Safety / HACCP Checklists (with automated temperature capture) Cooling Validations (when used in conjunction with DigiTrak RF) Training Certification Physical Inventory Counts (with barcode support) Plus, any other type of forms-based data collection process
The application includes management facilities for the creation, distribution and maintenance of checklist forms (in multiple languages), summary and detailed analysis reports, security access controls and audit reports, task scheduling and automated database backup. The back office functionality is browser-based (Microsoft Internet Explorer) and allows access to the management functions and reporting features from any PC with network connectivity. All access to the system is controlled through the use of centrally managed User IDs, passwords, roles and access lists maintained in the back office data store (in addition to standard operating system security controls). Operating either wirelessly (802.11b) or in batch mode, the Handheld DigiTrak-PDA application is used to complete the various checklists/forms and collect inventory count information. The collected information is transmitted immediately (wirelessly) to the back office server application and logged into a SQL database. The system can also operate in a non-wireless (batch) environment in which case collected information is automatically downloaded to the server when the handheld is placed in the serverattached cradle. There is no intervention by the user required to initiate these transfers and multiple forms (sessions) can be completed before cradling. The system also includes the ability to establish logical condition tests (i.e. range / bounds checks) that can notify a handheld user immediately if certain parameters are out of acceptable limits or range while completing a checklist (i.e. product temperature too hot or cold during a food safety checklist). Based on user responses or unacceptable temperature readings, immediate Corrective Actions can be presented to the user and are stored along with the form/checklist information.
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A variety of question types are available to the forms designer and forms presented to the user can include graphics and images if appropriate. No programming is required to design and create the forms for the PDA.
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Technology Overview
Handheld Platform
H ARDWA RE / OS • Symbol PPT 2800/8800 or similar ruggedized handheld device (recommended) or any other PocketPC 2002/2003 based handheld (i.e. iPaq, Dell, etc) • Microsoft PocketPC 2002 or 2003 Operating System • 64MB Memory • 802.11b Wireless and Batch (cradle) supported (Serial or USB) • Thermocouple Temperature Acquisition Device & Probe S OFTWARE • DigiTrak-PDA MobileRuntime client • DigiTrak-PDA Server Communication and Synchronization Libraries • Speech Recognition Libraries (optional)
Back Office Server Platform
H ARDWARE / OS • Microsoft Windows NT 4.0 (SP6a), 2000 Professional/Server or XP Pro • 256MB Memory • 1.2GHz Processor or faster • CD-RW Drive (For unattended, automated database backups) • 1 Available RS-232 Serial Port (for initial PDA setup and batch mode operation) S OFTWAR E • Microsoft Internet Information Server (IIS) • Microsoft SQL Server 2000 (MSDE version) – (supplied with software) • Microsoft ActiveSync 3.5 • Handheld Communication Server (including task scheduler) • DHCP Server • Automated handheld version synchronization utility • Automated database backup and compression facility • DigiWare IIS-based application administration (ASP) • External Inventory & Employee integration utility • Digitron Form (checklist) Import / Export Utility
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Development Environment
The DigiTrak-PDA application has been developed using the Microsoft SQL Server database system as the underlying data store and makes extensive use of stored procedures for encapsulating common data access functions. In addition, the applications are written using a combination of the following development tools: • • • • • • • Microsoft Visual C++ Microsoft Visual Basic ActiveX Component technologies Microsoft Embedded Visual C++ for PocketPC 2002 Symbol Windows CE SDK Microsoft Active Server Pages (VBScript) HTML / JavaScript / Java via IIS/Internet Explorer
Communications Overview
All communications between the handheld device and the back office server is via industry standard 802.11b Wireless LAN protocols when operating in the wireless mode. On top of the 802.11b infrastructure the application transfers data in a compressed format using the TCP/IP protocol. The communications server application running on the back office server is responsible for interfacing with the database system and other application modules. The Handheld device has no direct interface to the underlying data store. In the event of a communications link failure (out of network range, Access Point failure, back office server failure, etc), the application services on the handheld device (MobileRuntime) will automatically retain the checklist collection information until the communications link is re-established at which time the connection is automatically detected by the application and the information is delivered to the back office server (i.e. there is an automatic switch-over to “batch” mode on the handheld when the network link is lost, and a switch back to “wireless” mode once the network connection is detected again – all without user intervention). The user will receive a visual icon notification that the network connection has been broken on the handheld device. During a network failure, the handheld device is fully functional for continued checklist collection tasks (i.e. a user can continue to complete Quality / Inspection checklists, Food Safety checklists or Training Certifications, switching between them as necessary), with all information saved until the link is re-established.
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Handheld Application
The handheld application (MobileRuntime) is a multi-threaded “thin client” program that optionally provides a “lockdown” environment on the handheld (i.e. restricts access to the standard PocketPC applications/games/utilities) and manages all user interface generation and interaction. Access to the application is controlled by requiring the user to enter a username and password that is validated by the back office. All valid and invalid access attempts on a handheld device are logged and reported on the back office server. A schedule of tasks to be completed is also maintained by the system and automatically “prompt” the user on the handheld device to perform a certain checklist/form when required. In addition to managing the presentation of the checklist/form content to the user, the MobileRuntime program also provides a synchronization mechanism to transparently update all locally cached checklist information with updates from the server as soon as they are “published” into a production mode. This feature allows the handheld to function with or without network connectivity and also insures the user is working with the most recent version of a checklist. For any question or informational message presented to the user on the handheld, context-sensitive help can be defined to assist the user in completing the checklist. All checklists/forms can be created in multiple languages and the “native” language for presentation by the handheld can be administered on a user-by-user basis (i.e. each user can be presented the same checklist in their native language). In addition, temperature measurements can be displayed both on the handheld device and back office reports either in Celsius (°C) or Fahrenheit (°F), based on an individual user-level preference. Any handheld application updates deployed on the back office server are automatically detected by the MobileRuntime application and automatically downloaded to the handheld device. This greatly simplifies the update process for introducing new devices into a store or replacing a defective device.
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Unlike a browser-based system, the DigiTrak-PDA handheld application is tolerant of network outages due to equipment failure or moving out of the 802.11b RF network range. The user does not need to perform any additional tasks to complete a collection when the RF communications are re-established; the application handles this automatically, saving all information on the handheld until it can be delivered to the back office server. There are a number of additional benefits to this approach over a strictly browser-based interface: • BATTERY LIFE. Handheld battery life is significantly extended by drastically reducing the network traffic inherent in an HTML/browser application. With a browser application/HTML, you would need to request back to the server every time you took action. That would take a great deal of battery life and requires a reliable and persistent network connection. NETWORK OUTAGES. The system is tolerant to intermittent RF network outages, such as moving out of range of the Access Points. With a browserbased application, once a network connection is lost the application is typically rendered useless until the link is re-established. The system was designed with the assumption that RF communications could not be guaranteed 100% of the time and will work with RF outages without affecting handheld performance. COST. Total system cost is reduced, since less AP coverage is required (a single AP is all that is necessary in most cases). We are making use of Microsoft's SQL Server 2000 (MSDE edition) database system, which provides a lower cost-per-store implementation of the solution than an Oracle-based application. RELIABILITY. Data is completely saved on the handheld until communications are re-established and the data is delivered to the back office server - even in the event of a soft reset of the handheld. The JavaScript implementation is limited for the Pocket IE version of the browser as compared to the standard windows version of Internet Explorer. An application making heavy use of the implementation of JavaScript for the Pocket PC 2002 OS is then relying upon core functionality over which there is little control. SECURITY. The handheld can be "locked down", restricting a users access to the standard Pocket PC applications (Excel, Word, Internet Explorer, Games,
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etc). All application access is managed through a common set of user Ids, passwords, roles and functional access lists. • EXTENSIBILITY. A browser-based application would have no means of interfacing with an attached temperature reading device/probe or barcode scanner without the use of additional downloaded applets or ActiveX controls. PERFORMANCE. Redrawing the buttons, the screens and text every time you go forward or backwards in a browser would take time in addition to battery life and the system needing to be connected to the server. HTTP is not fast on the device, especially with the amounts of data that can be involved. The DigiTrak-PDA MobileRuntime engine is a multi-threaded asynchronous engine, downloading many of the tasks one-time in the background. MS Pocket PC IE does not support that functionality. Response time for the user is decreased (better performance) when interacting with the system in general.
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Other applications that would require constant network communications (i.e. Order Taking) can still co-exist on the same device without any problems.
Back Office Application
The DigiTrak-PDA back office application consists of a number of modules, including: • • • • • • • • • Handheld communications and form synchronization server (HHServ) Handheld application version update / management server (SLExec) Embedded DHCP Server (DHCPServer) Form/Checklist Import/Export utility (MRDBTransfer) Automated database backup utility (MRCDBackup) Handheld initialization / bootstrap utility (MRInstallServer) External ISP Server integration utility (ISPImport/ISPExport) Browser-based configuration, reporting and maintenance application Numerous Microsoft SQL Server stored procedures and custom views
The primary back office modules are multi-threaded server applications capable of handling multiple handheld connections simultaneously and are configured to execute as system services. All communication between the handheld devices and the back office server are initiated by the handheld application (MobileRuntime). All communications between the handheld application and the back office server application are compressed and encrypted (in addition to any WEP encryption that may be enabled on the wireless network devices).
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The back office reporting, configuration and administration functionality is browserbased (Microsoft Internet Explorer) and allows access to the management functions and reporting features from any PC with network connectivity. All access to the system (both back office and handheld) is controlled through the use of centrally managed User IDs, passwords, roles and functional access lists maintained in the back office data store. MRCDBackup provides an unattended backup capability for the entire DigiTrak-PDA database (to a local CD-RW) in the event of a catastrophic system failure. The database is stored to the DirectCD-formatted CD-RW on a regular, user-defined, schedule and maintains multiple days of historical backups with automatic FIFO cycling of backups on the CD based on available CD disk space. DHCPServer is a fully functional DHCP server application that can provide dynamically assigned IP addresses to the handheld (or other) devices on the local network. This functionality greatly simplifies network administration and the replacement process for the handheld devices.
External ISP Server Integration
The DigiTrak-PDA application also provides bi-directional integration with an existing back office Inventory system using batch mode transfers (via FTP). Information to/from the Inventory system occur on a regularly scheduled basis (or on demand) or in real-time and consist of the following categories: • • • Item Inventory information (item numbers, descriptions, status, unit of measure, count types, etc) Employee information (name, ID, role, status) Inventory physical count information (Item numbers, unit counts)
Through this integration, management of user and inventory item information is consistent and managed from a single point and does not require redundant
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administration. Common formats, such as comma-separated values (CSV) and extensible markup language (XML) are supported.
Form / Checklist Creation and Management
Forms / checklists presented to the user on the handheld device are designed and managed by the user via browser-based applications resident on the back office server. There are no “hard-coded” user forms or checklists embedded within the handheld application. As changes are made to the form content or new forms are created, the modifications are automatically and transparently migrated to all handheld devices through the version synchronization utility built in to the MobileRuntime application and server communication modules. The system includes full form/checklist authoring capabilities (that can be limited with appropriate security access controls) to allow creation of nearly any type of survey / checklist / form that may be desired in addition to the suite of “standard” checklists supplied with the system. This capability would allow, for example, the creation of a “Customer Satisfaction Survey” whereby an employee can take a handheld to the dining area and selectively question customers on their dining experience. Automatically, both summary and detailed reports are generated and available through the back office browser interface. Creation of any type of form does not require any programming capabilities or other specialized expertise and is performed by the user in a “filling in the blanks” interface. A wide variety of types of information can be captured as part of a form or checklist, including: • • • • • • Single line text fields Multiple line text fields Numeric value fields Temperature values (manual or via attached probe) Scanned barcode labels Stopwatch timer fields • • • • • • • Listbox choice selection Yes/No value fields Radio button choices Multiple-select checkboxes Informational messages Category / Section selection Date Fields
For many of the question types (i.e. Numeric values, Dates, Temperatures, Yes/No, Radio, Checklists, Listboxes, etc) the form designer can also create conditional logic to allow for additional information to be collected based on the value/answer selected. These conditional questions could be used to collect corrective action data or other information as required based on the user’s input. When collecting temperature data, the system can automatically perform validation checks and immediately notify the user of the temperature reading is out of spec. At that point the system can then either force the user to re-take the temperature and/or optionally prompt for corrective action steps.
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The forms designer can include form-level and question-level context sensitive help to assist the user in completing a task. Additionally, graphics and images can be displayed along with the question or context-sensitive help to provide further explanation or clarification when necessary. The system has a complete version management system for tracking form modifications and “publishing” version changes to the handheld devices. Report formats are automatically generated by the system as part of the form creation (i.e. there is no need to create/design a report when creating a new form or checklist), and in addition, historical reports reflect the form structure and content at the time the form was completed even if changes to the form have occurred since that time. Through the use of the Import / Export utility, form(s) can be designed on one system (i.e. at corporate) and exported into a compressed archive that can be delivered to one or more store locations via floppy, CD, email (or through the existing ISP maintenance process) and imported into the local store back office server.
• Create New Checklist • Export Form
• Deploy / Deliver (Mail/CD/Floppy)
• Import Form
• Automatic Deployment
The client portion of the DigiTrak-PDA application (MobileRuntime) functions in the exact same manner as a browser (such as Internet Explorer), in that form definitions are downloaded transparently to the handheld and rendered on the handheld display. The forms are NOT "hard-coded" into the application. The handheld client "engine" simply processes the form definition to walk the user thru the completion of the form questions and transmits the results back to the server for processing as soon as a network connection is available. For testing and debugging purposes there is also a “PDA Emulator” application that runs on the PC and functions identical to the PDA application (with the exception of the use of the temperature probe).
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Summary
The architecture of the DigiTrak-PDA is designed to provide a cost-effective, high performance and reliable solution for a batch or wireless handheld-based solution that fundamentally allows an organization to meet or exceed management objectives for building and managing quality-focused operational processes.
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