Adding a Calculation
This section describes the procedure for inserting a new calculation, which might include any combination of valid logical, Boolean, and arithmetic operations available to the user (for details about valid operations, see section 3.7 Additional User Calculation Information).
- Call up the User Calculations Directory display.
The User Calculations Directory appears, listing the available user-defined calculations.
There are two ways to insert a new calculation.
First method:
Click the Insert New Generalized Calculation button to insert a blank calculation at the end of the list.
Click the newly created button to bring up the User Calculations Operations display for that calculation.
Second Method:
Click the button for one of the existing calculations. The User Calculations Operations display appears, showing data about the calculation you selected.
Select the Insert GCALC option from the Insert or Delete Calculation (+/-) menu to insert a calculation at the end of the list in the User Calculations Operations directory.
Navigate to the new calculation by either using the arrows at the top of the display or returning to the directory and selecting the desired calculation.
In the Function field for the new entry, type a unique name identifying the purpose of the general calculation, and press Enter.
The name is accepted by USERCALC.
In the Period field, type a value for the number of seconds between each execution of the calculation, and press Enter.
The value is accepted by USERCALC.
(Optional) In the Start field, type a value for the date/time that the calculation should begin execution, and press Enter.
The value is accepted by USERCALC.
If no value is entered, the default is to begin execution of the calculation immediately on enabling the calculation.
(Optional) In the Stop field, enter a value for the date/time on which the calculation will automatically be disabled, and press Enter.
The value is accepted by USERCALC.
If no value is entered, the default is to only disable execution of the calculation on operator request.
Insert an input/output record for each input and output to the calculation.
Input/Output records can be inserted from the Usercalc Operations display in two different ways. Following is the first method:
- The first input/output record is present by default. To add subsequent input/output records, right-click the (+/-) menu next to the first input/output record near the bottom of the display.
For each input/output record, select the enterable field box to the right of the button. Then type a unique variable name, and press Enter.
The variable name is accepted by USERCALC.
For each input/output to the calculation, hold down the button labeled with a question mark, and select the desired type from the menu that appears.
The button is labeled “Analog” or “Point” according to the option you chose.
Type in the Substn, Devtype, Device, and ID fields and press Enter.
Enter values uniquely identifying the analog or point. If the variable is representing a locally displayed variable that is not associated with an SCADA Point or Analog record, these fields can be left blank.
The names are accepted by USERCALC.
Following is a simpler method for creating the records, if the Input/Output records are associated directly with SCADA Analog or Point records as inputs to or outputs of the calculation:
- Right-click the “Select calc as focus” text and select the Select Calculation option.
The calculation is marked as the active calculation to accept inserted SCADA Point and Analog records.
On the Substation Tabular display, the Point/Analog/Count view, locate the point or analog that you want to add as an input or output of the user-defined calculation. Select the Calculator icon.
An input/output entry is automatically inserted into the selected calculation with a default name, the correct type, and the Virtual ID information filled in.
Repeat step 2 for each Analog or Point record that you want to be an input to or output of the user-defined calculation.
For each added input/output record, set the Source field correctly.
If the record represents an output, or both an input and an output, select the entry below the column heading titled Source and select the OUT option.
If the record represents an input to the calculation, select the IN option.
If the record represents a locally displayed variable that is not associated with an SCADA Point or Analog record, select the LOCAL option.
SOURCE records contain text input lines in which to enter calculation formulas. For each formula line required by the calculation, insert a SOURCE record.
The first SOURCE record is present by default. To insert more SOURCE records, select the (+/-) menu located to the left of the existing formula record and select Insert SOURCE record.
For each SOURCE record inserted, select the enterable field box to the right of the button. Then type the source line text, and press Enter when done.
The text of the calculation is accepted by USERCALC.
A list of valid general calculation operators, as well as examples of valid and invalid general calculations, is described in section 3.7 Additional User Calculation Information.
Once the records have been added, click the Validate button located under the Stop field. The calculation is validated for good syntax and valid inputs and outputs. If the calculation is validated, the button will turn into an “Enable and Run” button and the calculation is marked “Disabled”.
Click the “Enable and Run” button, which will remove the ability to edit fields and change the button into a “Disable and Edit” button.
The USERCALC function begins execution of the newly enabled general calculations. The Next Run Time field is updated each time the calculation is executed. When the USERCALC function begins execution, the Status of the calculations is changed to “Enabled”.