JSENT is a SCADA system suitable for a variety of applications such as vehicle traffic control, PLC factory control and telemetry/telecontrol systems. JSENT consists of two main building blocks, a back-end server and a HMI front-end, which communicate with each other over a TCP/IP network. These two components may be present in the same computer. SCADA main component is: server, database, web page server, ftp server, trends, reports, sheduler

The server consists of a number of services. One is a 'in-memory' real time data base. Other services provided are user access control, drivers for external systems, logging to SQL data bases, alarm and event lists, and application specific facilities.


Real time data base holds the current values of the real time data obtained from external devices.

  • Event driven throughout for maximum performance.
  • Hierarchical with no limit to nesting of components.
  • Sections can be cloned and refer to a master copy. Changes made to the master copy are reflected in all the clones. Used to quickly create or duplicate similar data base blocks, such as similar PLC's, RTU's or traffic controllers
  • Number of tags only limited by memory and license restrictions. Largest system currently is 750,000 tags.
JSENT is supplied with the open source databases Derby and MySQL. It has also been tested with MS-SQL server. Derby is the default SQL server for JSENT and is free to use. Users wanting to use MySQL will have to purchase a licence from MySQL. JSENT can easily be adapted to other standard databases, such as Oracle.

Beside internal configuration data, event, trending and current alarm information is written to the database. The embedded web server provides the platform for a web-centric view of the JSENT system.

The web server is used for:
  • Reports. JSENT reports are HTML pages managed by the web server.
  • Alarm list. This password protected area of JSENT allows an engineer to view and accept alarms.
  • Event and other SQL tables.
  • Documentation.
  • Client deployment. Running the JSENT HMI from a networked client is as simple as clicking on a web page link.
An FTP server is embedded in JSENT. This allows remote maintenance of the JSENT server. JSENT The user access control is done through the standard JSENT password control mechanism. JSENT maintains a global alarm list as well as 'mini alarm' lists.
  • The global alarm list shows all current alarms in the system.
  • Mini alarm lists show alarms on sub sections of the system, for example plant items or RTUs.
  • New alarms can be configured to be either accepted or unaccepted. Unaccepted alarms must be acknowledged.
  • The current status of the global list can be maintained on the SQL server.
Trending captures historical data for later viewing and analysis using the HMI chart viewer or with a standard spreadsheet.
  • Trend data is written as records into SQL tables.
  • Any number of simultaneous trends can be active.
  • An unlimited number of tags can be linked to each trend.
  • Various conditions can be configured to enable a trend, to take a set of samples and to revert the trend to the inactive state.
  • Old trend data can automatically be archived and purged.

JSENT can create sophisticated reports. The report writer creates HTML files from user defined template files. These templates are standard HTML files that have embedded Python script code. Reports are not created dynamically when the user requests them but are created once and held as web pages. Once a report has been created it can be automatically printed and a SMS message can also be sent.

The scheduler is used to issue commands at predetermined dates and times. It is typically used to do backups, print reports, issue reminders at appropriate times. The scheduler works with a number of day plans. Each day plan is a list of times and actions that must be performed at that time. There could be a day plan for weekdays, another for Saturdays and another for public holidays.

JSENT can send SMS messages, either when a tag goes into alarm or manually via a GUI or under scripting control. A SMS message can be sent to individual cell numbers or to a group of cell numbers. These groups of cell numbers are configurable.


JSENT's innovative Datascript is a powerful yet easy to use scripting facility that is designed for end users. It abandons the conventional scripting approach which normally requires a high level of expertise and an understanding of programming techniques and languages. Instead, the script is created by placing and linking predefined process on the screen. The result is a flow chart like diagram, but it is even more intuitive because it works with specific data objects, not the abstract logic of a flow chart.

There are four basic areas of JSENT that can be scripted: server scripts, HMI scripts, click scripts, mimic scripts.

Because JSENT is written in Java it is portable across a wide range of operating systems. It has been tested on Windows NT, 2000 and XP,Red Hat and Mandrake Linux, Linux and Windows workstations and servers.

The JSENT HMI consists of a number of panels, each panel holding an application. These applications may be shown either as a series of tabbed panes where each pane occupies the entire screen area or as overlapping windows.

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