Web Based Calculator

Background

Roche Vitamins contacted us in July 2001. Roche Vitamins have been very good customers and have implemented PPDS throughout their sites. However, like many IT users these days, Roche Vitamins were interested in ways of ensuring that client machines were kept up to date with the latest versions of the software. PPDS2 for Windows' Client / Server architecture satisfies this very well - the banks and calculation engine are all housed on the pc hosting the PPDS Server. Roche Vitamins' immediate problem was their extensive use of custom Excel Spreadsheets interfacing with the PPDS Server. While their spreadsheets would not be affected by upgrades to the PPDS installation, they also would not benefit from new or improved server side functions unless the client spreadsheet was updated. While this particular problem could be lessened by using centrally stored spreadsheets, there was still the overhead of installing client software.

Client / Server software, by its very definition, consists of software installed on both client and server machines. In a nutshell, the user interacts with the client side code either through a graphical or a programmable interface. The client code communicates with the server code to pass the requests and receive the results. The results are then handled by the client software and displayed to the user. Before the client software can talk to the server code, various configuration steps have to be taken. These steps include adding code libraries and configuring the registry for the PPDS client extensions. We use the installation program to take these steps as that is the easiest, most direct way of performing the task. The downside of this is that client software must be installed on each machine that is likely to access the PPDS Server. For larger organisations located at different sites with different IT-policies this means a considerable investment in time if many users require access to the software.

As Roche Vitamins wanted to encourage greater access to the PPDS software, this issue would have to be resolved.

The obvious solution was to develop new tools for Roche Vitamins to use over its corporate intranet. Due to the nature in which web sites work, only the web server would require the PPDS client extensions to be installed. All users could use their preThis would use the built in functionality of the PPDS programmable interface.

The key advantages of this solution was that:

• The intranet was already well established within Roche Vitamins as a tool. This meant that the users would need little or no encouragement to access web based tools;
• Deployment would be straight forward - the browser application would be installed onto one location on the intranet;
• No client configuration would be necessary provided those client machines were already capable of viewing the intranet;
• The browser application could sit alongside the existing spreadsheets and interfaces that had already been developed.

A detailed specification was agreed and the work to produce an intranet based browser application to replace Roche Vitamins' existing spreadsheets for determining temperature dependant saturation line properties began in Nov 2001.

Development

The tight specification was an essential element of the design work for the intranet application. In it, Roche Vitamins detailed their requirements in terms of both functionality and usability. This, coupled with close contact with Andreas and Urs Blaettler via email and telephone throughout the development and testing phases, ensured that Roche Vitamins were not surprised with the application when they received the final version.

The functional design of the tool is quite straight forward. The user specifies a component either by bank/component number pair or by searching for it. Once entered, the user selects the interested phase and supplies a range of temperatures that the calculations are to be performed over.

The generated output is in three sections: name information including synonyms, CARN and formula; identified constant properties; and a table of properties over the range of temperatures requested.

As the typical browser user will have no other PPDS material available, a new method of displaying the output quality codes needed to be implemented. The method chosen uses colour coding to identify the differing codes. A popup legend explains the codes to the user.

With only some minor configuration issues (it is impossible to effectively test bespoke software unless you can precisely reproduce the customers environment) the browser appliation was installed and configured on their site on 6 December 2001. Leaving Andreas and Urs to examine the documentation and test the system, I returned on the 7th to perform some minor configuration and formatting changes that enabled the application to more fully integrate into their intranet.

Roche Vitamins then tested the application over the next couple of weeks and, after having another formatting item corrected, stated that they were so pleased with the intranet solution that they wanted to extend its capabilities.

The new specification was equally specific - the existing application was to be upgraded to allow plotting of selected properties over the specified temperature range. Additionally, an option to display the ideal vapour properties should be implemented. Finally, both real and ideal vapour properties should be plotted when the real properties were requested.

Armed with this tasklist development began in April 2002.

The charting capability was supplied by SoftwareFX's ChartFX graphing tool. This tool is a powerful tool that is straightforward to implement. Client graphs can be either static images or interactive charts (although this requires the client to download a relatively small library). Interactive graphs can have their appearance modified and the data cut and pasted in spreadsheet ready format.

The graphs would be activated from a button at the bottom of each property column. On pressing the button, a popup window would be opened with the desired graph displayed. Although popup windows can be an irritation, it was felt that in this situation being able to keep previously generated graphs open would be an advantage. Furthermore, it eliminates the need to recalculate the complete results page after viewing each graph. As these windows can accumulate, the ability to close the window was added to each page. We also added the ability to print the graph from the window.

Development and testing was completed in early May 2002. The application and supporting documentation (this time only on one cd) was couriered over to Roche Vitamins for installation and configuration.

Where is it now?

Since deploying this intranet calculator tool, Roche Vitamins has been split to form ****** and *****. At the present time both new companies continue to sue the calculator.