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This TechNote describes the three basic methods of creating simple controls in WaterGEMS and WaterCAD. This workflow also applies to logical controls in SewerCAD or SewerGEMS using the GVF-Convex solver. WaterGEMS will be used as an example in the workflow flow.
In addition to general information on creating controls, assigning a particular set of controls to a scenario using Control Sets is also described later this Technote.
Note : This TechNote is applicable WaterGEMS and WaterCAD CONNECT Edition or V8i SELECTseries 6. Here is the technote for older versions of the water products.
In WaterGEMS, controls can be modeled to introduce a user-defined action to a hydraulic element. When one or more conditions provided by the user are met during the model simulation, the action or actions provided by the user will be introduced in the model operation. In a real system, these types of controls are sometimes referred as Programmable Logical Controls (PLCs). SCADA systems and time-based plant operations are major sources of PLCs that should be included in a water model. Including controls in the model is most essential when performing an Extended Period Simulation (EPS).
Controls can be created for a number of element types, including pumps, variable speed pump batteries (VSPB), valves, and pipes. The example below shows controls for pump status based on tank level, but a control could also be other element types or conditions. In addition to basing conditions on element properties, conditions can also be set for Time of Day, System Demand, and Time from Start.
Note: If you are using SewerCAD or SewerGEMS with the GVF-Convex solver to model logical controls, the elements in the condition and action should be in the same pressure subnetwork.
There are two methods to access main Control dialog. First, you can go to the Home tab and select Controls or the Components tab and select Controls. For V8i SelectSeries 6, go to Components > Controls.
When you open the Controls dialog using this method, all controls in the model will be displayed as the default. You will find a series of pulldown menus at the top of the dialog for Controls Set, Condition Element, Action Element, Type, and Priority. By choosing from these menus, you can filter the list of controls based on the selection.
The second method you can open the Controls dialog is through the Properties. In the Properties grid, find the Operational section and click the ellipsis (...) button in the Controls cell. This will open the Controls dialog filtered on the element. In the example below, the Controls dialog is filtered on PMP-2 and the control set for the active scenario.
Below you will find the methods available to create controls.
Creating controls using the Control Wizard is very simple and can save time. However, this approach is only applicable when creating controls on pumps that operate based on tank hydraulic grade results. To use the wizard, click the 'Control Wizard' button in the Controls dialog.
Next, select the pump to which you want to assign a control from the drop-down list.
Next, select the tank from the drop-down list. This will be the tank that the pump status will be based on.
Next, set the On Operator and Off Operator. You would typically use operators like the such as greater than '>' or less than '<' options. Also set the On HGL and Off HGL.
Click the Create button to complete the process. This will create new conditions related to the tank and new actions related to the pump. The control will be created and visible in the Controls tab of the Controls dialog. Please scroll to Control Set for further information on setting up a control set the new control
This method allows you to create both conditions and actions in one place, directly from the Controls tab.
First, click the New button. You will see a new control that is essentially blank. At the bottom of the Controls dialog are several buttons and pulldown menus. The left section is for defining Conditions, the middle section is for defining Actions, and the right portion is for defining optional ELSE Actions.
Notice there is a new control that is undefined ("IF <none> THEN <none>"). You can now use the options available at the bottom of the Controls dialog to either select an existing condition or action or create a new condition or action. Note: If you need to create a new composite condition or action, you must first create the condition or action in the respected Conditions or Actions tab. See the next section for details.
Next to the dropdown menu for the IF, THEN, or ELSE statements, you will see three small buttons.
With the button on the left, you can create a new control. For the IF station or condition, you will be able to select the type condition (Clock Time, Element, System Demand, Time from Start). If you select the Element option, you can use the pulldown menu to select from elements that have already been used as a condition. You can also use the Select or Find buttons next to the pulldown menu to select an element from the model. For the THEN statement or action, you can select an existing action from the pulldown menu or use the Select or Find buttons next to the pulldown menu to choose an element from the model.
c. In the left portion of defining conditions, you have option of creating simple or composite condition using the small drop-down arrow.
d. While selecting the element using 'IF' condition, instead of selecting from the drop-down list, you have new option of selecting the condition from the list of conditions created, rather than browsing one by one from the drop-down list for existing conditions, suing small black arrow or small search button.
e. Follow the steps in the image below to create a condition. Note that the actual conditions and actions shown will be specific to your own model.
f. Follow the steps in the image below to create an Action for your condition. Again, the actions displayed are specific to your model.
g. After creating the conditions and actions, the Control dialogue box should look something like below:
This method allows you to create conditions and actions separately under the Conditions and Actions tab. It is necessary to use this approach when creating a control with multiple conditions and or/actions (i.e., a composite condition or action) using AND or OR.
a. To create a condition in the Conditions tab, follow the steps in the image below.
b. Next, create and Action in the Actions tab by following the steps in the image below.
c. After creating Conditions and Actions, go to the Controls Tab and select the New button to create a new control. In the lower part of the window, select the Condition and Action(s) you created in the previous steps to build the desired control.
Control sets allow you to manage and modify controls. The use of multiple control sets enables you to apply different controls to different scenarios.
This section describes how to set up control sets themselves. Details on assigning a particular Control in a particular scenario are provided in the next section.
To create a control set, select control set icon ( third from left), click the drop-down list and select 'Add / Remove Control Sets', which will open the list of control sets.(see "third option" in image below). The count field lets the user know how many controls are included in a given control set. You need to create a control set in this window before you can begin associating controls to it as shown in the “Control Sets” window above.
To include a control in your control set, select second option from the drop down list - Edit Control sets. To make this option active select any control in the controls list (as highlighted in the second image below). This will open the Editable control sets dialogue.Repeat this process until all of the desired controls are in the selected items list, and then click OK.
To open the control sets for multiple controls, select multiple controls using Ctrl button or using the shift button, and then select edit controls sets.
The below dialogue box contains, the conditions and actions columns of controls and also else option for composite controls. the right hand side editable columns are of the controls sets. By checking the box nex to controls, of particular control set , it makes the control active for that control set. you also have option of global editing the columns, meaning making the controls active or inactive for a particular control set in one go by right clicking on the column of say "Variable Speed Pumping" control set>Global edit. Also you can filter or sort the controls based on the status on/off.
To make controls scenario specific, it is necessary to add controls to a control set, as previously described, and then assign that control set to the Operational Alternative utilized by the desired Scenario.
Open the Alternatives dialog and either edit the existing Operational Alternative or create a new one, if needed. Double-click the alternative to edit it (see "1" below).
Click the down arrow ("2"), select the desired control set ("3"), and then click Close to save your changes.
c. Finally, if you created a new Operational Alternative, you will need to edit the desired Scenario's Operational Alternative so that it uses the new one.
To identify whether an element has an active control, look for the following symbol next to the element. If the symbol is not present, then it's likely the control you created is not assigned to the control set being utilized by the current Operational Alternative.
You have the ability to add a priority value to a control to control cases where multiple controls have conflicting actions. To set a priority for the control being created, it needs to be a logical control. To activate the priority drop-down list, click the check box next to Priority.
You can set a priority of 1-5, with 5 being the highest priority. If multiple controls meet a certain condition and they have conflicting actions, the logical control with the highest priority will be used.
Note: At calculation time, the priority is used to determine the logical control to apply when multiple controls require that conflicting actions be taken. Logical controls with identical priorities will be prioritized based on the order they appear in the 'Logical Control Set' in the 'Operational Alternative'. A rule without a priority value always has a lower priority than one with a value. For two rules with the same priority value, the rule that appears first is given the higher priority.
It is important to note that priority only works with Logical controls (with the "logical control" box checked). If priority does not appear to be working, check to make sure that all controls with conflicting actions are set as logical controls.
Note: If you are using SewerCAD to model logical controls, the control priorities apply to individual pressure subnetworks. For that reason, if you have conflicting controls that involved elements in different pressure subnetworks, such as two controls that have two different tanks as the condition, you will need to make sure that there are no gravity elements between the elements referenced in the control.
Controls can be duplicated depending upon your requirement, whether you want to duplicate only control or conditions and actions as well.
Starting with the CONNECT Edition release of WaterGEMS and WaterCAD, you now have the ability import and export controls from one project to another. This will save you time in recreating the controls for new projects.
The tanks element received a new “Percent Full” condition option that will allow you to specify a given action to occur when your tank gets to a certain percent level full.
There are also newly added actions for the pump element that will allow you to create a control to have a pump achieve a target pressure and pump target head, which will be useful for VSP pumps. For more on this, see further below under the VSP section.
If your controls do not appear to be working as intended, see the following article for troubleshooting steps: Controls not being followed
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