Enabling the HTTP Server

To use the EOS SCADA Runtime HTTP Server, the relevant feature must first be enabled in the project settings. The server is activated by setting the HTTPServerActive option to true in the project configuration.

  1. Open the project's Project Settings section.
  2. Set the HTTPServerActive option to true.
  3. Refresh the project so that the settings are applied by Runtime.
  4. Check the Runtime status bar to verify that the HTTP Server is active.

Active status indicator: When the HTTP Server is successfully enabled, HTTP SRV is displayed in the Runtime Status Bar, and a green LED appears next to it. This indicator provides a quick way to verify that the embedded HTTP Server is running.

Accessing the Web Gateway

After the HTTP Server is enabled, the EOS SCADA Web Gateway can be accessed from any web browser using the IP address and port defined in the project settings.

General access format:

http://IP_ADDRESS:PORT/command?parameter

Example:

http://10.240.162.74:80/command?parameter

The IP_ADDRESS and PORT values correspond to the HTTP Server configuration used in the EOS SCADA Runtime project. The command specifies the operation requested from the server, while the parameter specifies the scope of the data to be returned.

Note: The information provided by the EOS HTTP Server is read-only. This interface is intended for displaying SCADA data and transferring it to external systems; it is not used to modify process values within Runtime.

Role of the EOS HTTP Server

The EOS HTTP Server acts as a gateway between EOS SCADA Runtime and end users. By providing the SCADA data available within Runtime through the HTTP protocol, it enables access through standard web browsers and HTTP-enabled applications without requiring a separate SCADA client to be installed.

Incoming HTTP requests are evaluated according to their commands and parameters. The requested information is converted into the appropriate output format and sent to the client. Thus, the same SCADA data can be provided in JSON/XML format suitable for machine processing, HTML format suitable for user viewing, or PNG charts for visual analysis, depending on the requirement.

Output Format Purpose
XML Retrieving SCADA information as structured XML data.
JSON Providing a data structure that can be easily processed by web applications and software.
HTML Table Displaying data directly in a web browser in tabular form.
PNG Presenting specified SCADA data as historical charts.

Supported HTTP Commands

The EOS HTTP Server supports various commands for different data access requirements. The command specifies the type of operation in the URL, while the parameter following the command specifies which data and what scope of data should be returned.

Command Description Output
gettesis Returns the plant/project name. XML
getxml Returns the requested SCADA data in XML format. XML
getvalue Returns the requested SCADA data in JSON format. JSON
gethtml Returns the requested SCADA data as an HTML Table. HTML
getgraph Generates a chart of the specified data for the specified time range. PNG

gethtml automatic refresh: The HTML Table generated by the gethtml command is automatically refreshed every 15 seconds. This feature makes it easier to monitor live SCADA values through a web browser.

HTTP Server Parameters

The parameters used with the commands specify which SCADA data should be returned by the HTTP Server. The basic supported parameter formats are as follows.

Parameter Description
all Returns the current values of all data defined in EOS SCADA.
selected Returns the current values of all data selected in EOS SCADA.
DATA1:DATA2:... Allows the requested data names to be listed separated by colons (:). Only the current values of the specified data are returned.

Requesting specific data: When multiple data items are to be queried, their names can be separated by colons and sent within the same parameter. 

DATA1:DATA2:DATA3

Generating PNG Charts

The EOS SCADA Runtime HTTP Server can also provide historical values of SCADA parameters as charts. The getgraph command is used for this purpose. The number of data items, data name, time range, chart dimensions, and resolution are specified as parameters in the chart request.

getgraph parameter structure:

number of data items&data name (or names)&time range (minutes)&chart width (pixels)&chart height (pixels)&chart dpi value
Order Parameter Description
1 Number of data items Specifies the number of data items to be displayed in the chart.
2 Data name / names Specifies the names of the SCADA data to be included in the chart. Multiple data items are separated by &.
3 Time range Specifies the period covered by the chart in minutes.
4 Chart width Specifies the width of the PNG chart to be generated, in pixels.
5 Chart height Specifies the height of the PNG chart to be generated, in pixels.
6 DPI Specifies the chart resolution as the number of pixels per unit length.

HTTP Request Examples

Example 1 — Retrieving All Data in XML Format

The following request retrieves the current values of all data defined in EOS SCADA in XML format. 

http://10.240.162.74:80/getxml?all

Example 2 — Retrieving Selected Data in JSON Format

The following request retrieves the current values of the data selected in EOS SCADA in JSON format. 

http://10.240.162.74:80/getvalue?selected

Example 3 — Retrieving Specific Data as an HTML Table

In this example, two data names are specified and separated by a colon. The server returns the requested values in HTML Table format. 

http://10.240.162.74:80/gethtml?%I0.0@UNITE1.KEPEZ2.EUAS:%I0.1@UNITE1.KEPEZ2.EUAS

Example 4 — Retrieving a PNG Chart for a Specific Data Item

In the following example, the last 10 minutes of data are requested for one data item, and the chart is generated at a resolution of 300 DPI with dimensions of 640 × 480 pixels. 

http://10.240.162.74:80/getgraph?1&%I0.0@UNITE1.KEPEZ2.EUAS&10&640&480&300

Interpreting the examples: The part after / in the URL specifies the command, while the part after ? specifies the parameters associated with the command. The & character is used specifically to separate parameters in the getgraph command.

Use Cases of the EOS HTTP Server

The EOS HTTP Server can be used to provide SCADA data to different users and applications in a controlled manner. It provides a practical access layer, particularly for scenarios such as quickly viewing data from standard web browsers, supplying data to web-based monitoring applications, and presenting historical data as charts.

Requirement Recommended Command
Retrieving all SCADA values in a structured format getxml?all
Processing selected values in software applications getvalue?selected
Monitoring specific values as a table in a web browser gethtml
Visually reviewing historical values getgraph

Summary

The EOS SCADA Runtime HTTP Server is an embedded Web Gateway that makes data within SCADA Runtime available to external systems through the HTTP protocol. Activated by enabling the HTTPServerActive option, this architecture provides data access in XML, JSON, and HTML formats, while chart access is provided in PNG format.

Through its command- and parameter-based structure, users can query all data, selected data, or specific data names. This approach provides a simple and functional access mechanism for integrating the existing EOS SCADA Runtime data infrastructure with different web applications and monitoring solutions.

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