WaterGEMS/CAD enables a user to run an EPS analysis and display the results in a SCADA HMI. The process is summarized in the figure below. The blue boxes are the work flow for a user. The orange boxes are configuration steps that are set up once (unless changes are needed).

Model results are not directly displayed in the HMI. As is typical of SCADA systems, values are placed in an OPC server and these values are then displayed from the OPC server to the HMI. Therefore it is necessary to define mappings from the model to the OPC server tags and then identify which tags are displayed in which locations in the HMI. ("Tags" refer to the name of a property in the server.)

Configuration Steps

Because there are numerous brands of OPC servers and HMI software, it is not possible to give detailed steps on setting up the server and configuring the HMI. Users are referred to the documentation of those individual products for instructions. The user needs to install the OPC server and the HMI software before running WaterGEMS/CAD SCADA simulations. The server can be set up on the computer running the model or hosted on another computer networked to the model.

It is best to use the same versions of the server and software that the system operators are using so that users will be familiar with the software. It may be possible to make a copy of the server and display files for use with the model. However there is not a one-to-one relationship between model parameters and values that are displayed in the operator's HMI. The model can calculate far more properties at more location than the SCADA system but the model is not concerned with non-hydraulic properties. This can be visualized as shown below. The properties in the blue box are an example of information that can be provided to the HMI from the model that is not available from the SCADA system.

Once the OPC server is set up, the user can define the tags that are to be published from each model run. These would normally include the hydraulic properties that are displayed in the SCADA system but can include a wide variety of values that the model can generate. (These are essentially "software sensors" as opposed to the physical sensors in the field.) Before associating model element with SCADA tags, the user must set up the tags in the SCADA OPC server in accordance with the procedures for that server.

The mappings from the model to the server are set up by selecting Analysis > SCADAConnect Simulator > SCADA Results Publishing ( in the Configure tab of the SCADAConnect Simulator dialog).

This opens the SCADA Results Publishing table where the user defines which properties are associated with each tag in the server. The first time this is done, the user must first pick the OPC server by selecting the fourth button.

If the server is on a different computer than the model, the user identifies this by checking the Host box and navigating to the server location using the ellipse button.

The user can also specify the units associated with the values in the OPC server which may be different from the values in the model.

The user then fills in the SCADA Results Publishing Table by specifying which model element and property are associated with each tag. If the user does not wish to use to publish the result for a given property in a given run, the Enable box should be unchecked.

Once the mappings are complete, when a model run is completed, the results can be published to the OPC server for use in the HMI.

When model results are associated with a tag in the OPC server, the user must define how the result value is displayed in the HMI. It is best to model this behavior after the actual HMI although, as stated above, not all the values in the HMI are hydraulic values and the model can populate more tags than the actual HMI. The user can create a new set of HMI screens or can modify the existing screen to accept additional values.

Model to HMI Work Flow

Once the mappings from the model to the OPC server and on to the HMI display have been completed, the results of any model run, for which the Calculation Type is designated as SCADAConnect Simulator, are available for display. At the start of a SCADA runs, a series of checks are made to determine such things as whether a tag is available in the OPC server for each mapped property or if a model element is active for each tag. Any errors or warnings can be found in the SCADA Log which is shown in the Configure tab of the SCADAConnect Simulator dialog.

When the HMI is started, the results will be those corresponding to time 0. To advance to different times or run continuously, the user must open the Time Browser (Analysis > Time Browser). The user can advanced time using the buttons at the top of the dialog or pick a specific time to view from the list of times in the lower portion of the dialog.

The controls for the HMI such as panning, switching screens etc. depend on the brand and version of the HMI and instructions can be found with that software.