How can I publish my computed model results to a SCADA HMI?

  Product(s): WaterGEMS
  Version(s): CONNECT Edition,
  Area: Output and Reporting


Starting with V8i SELECTseries 6 of WaterGEMS, the user can publish computed model results to a SCADA HMI (Human Machine Interface) screen by way of an OPC server. This can be a powerful way for Operators (without experience with WaterGEMS) to simulate a future event and see what happens in the system using a user interface that is more familiar to them - the actual HMI screen.

This ability of SCADAConnect Simulator to publish results is independent from its ability to import data from a SCADA and display along with model results. SCADA Signal elements are not required for results publishing, as the model elements are directly mapped and published to OPC Tags.


  • There is no need for SCADA elements when publishing to an HMI, as the connection is made directly between a model element and a special OPC connection "tag".
  • The only thing that needs to be configured is what you see in the "Define OPC Server Connection" button at the top of the SCADA Results Publishing dialog - see below.
  • You will need to run a scenario with the Calculation Type (set in the Calculation Options) set to "SCADAConnect Simulator" and use the Time Browser to change timesteps. A timestep change will initiate publishing of the results for that timestep to the OPC server and thus to the HMI screen.
  • You will need an OPC Client and Server software such as "KEPware" or "Matrikon".
  • You may want to configure separate tags/channels on the OPC server and configure the HMI accordingly, so as not to interfere with your production HMI screen.
  • You may need to use 32-bit version of WaterGEMS, due to compatibility issues between same OPC clients and the 64-bit version of WaterGEMS
  • Be sure to set units using the "Publish Units" tab of the OPC Server Connection dialog. In some cases the actual HMI screen that reads from the OPC server could potentially further convert units.
  • To troubleshoot problems with the display of values in the HMI screen, check the value stored on the OPC server. For example in some cases an "OPC Quick Client" can be used to view the number stored in the OPC tag that SCADAConnect simulator is publishing to.
  • Tank HMI publishing may not work right if there's also a SCADA signal on the tank, since it may be trying to import initial settings at the same time.
  • When mapping valve status and pump status, the "is open?" attribute is exported. Meaning, a boolean is exported, with True (1) for when the pump or valve is open, and False (0) for when the pump or valve is closed. Note that if this particular status field is not working properly, try using the FLOAT data type.

Steps to Set Up Results Publishing

NOTE: older versions of WaterCAD and WaterGEMS have a different user interface in SCADAConnect, so the steps and screenshots below may look different. Check the links in the "See Also" below for information on using SCADAConnect in older versions.

1) To publish model results to a SCADA HMI, Open SCADAConnect Simulator from within WaterGEMS, navigate to the Configure tab and click the Results Publishing button.

2) Populate the rows in the table with the model elements you would like to publish, the attribute and the corresponding OPC tag to publish to.

3) Click the OPC Server Connection button and confirm that your server shows up. This requires an OPC Client and Server software installed and configured properly.

If this has already been done and you do not see the name show up next to "OPC Server", or if you cannot connect via the "host" option, try opening the 32-bit version of WTRC/WTRG using the WaterGEMS.exe file from within the root of the installation folder.

4) Next, click the Publish Units tab and change the units as needed.

5) Click OK Twice. At this point, an operator can use the SCADAConnect Simulator screen to set up an event that they would like to simulate, then select a Baseline Scenario and compute. The Time Browser button can then be used to publish results to the HMI screen. As the timestep is changed, results for that timestep will be published to the OPC server and the HMI screen will read from that.

Note on using custom HMI:

SCADA results can be published to any OPC Server that conforms to DA and HDA OPC standards. In some cases there is custom HMI available which is built as per specific requirements. In such cases, the HMI can read from the OPC Server and display the results. WaterGEMS publishes the results to the OPC Server and the HMI then reads from the server. This allows the use of custom HMI's as long as the results are successfully published to the OPC Server.

See Also

SCADAConnect Simulator for WaterGEMS V8i SELECTseries 6

SCADAConnect Simulator in WaterCAD and WaterGEMS V8i SELECTseries 5

SCADAConnect in SewerGEMS

Will SCADA Results Publishing work with only OPC sources?

Automatic processing of results (or other) data using an extensible data exchange framework