Variables
Last updated
Last updated
As in all SCADA software, the most important basic component in the inSCADA platform is "Variable", known as "TAG" or "POINT" in other SCADA platforms.
As shown in Figure 1, "Variable" is the labeling of the values that we read from the communication channel. It ensures that the values we read from the devices we communicate with are tagged to the inSCADA platform and used as a variable within the platform. Similar to variables defined in programming languages.
As in any programming language, the most important feature of variables is their type. Although they vary slightly according to the programming language we use, they have close definitions (e.g. Float, Double, Boolean).
The type designation in inSCADA specifies the format of the data in the device from which it is read. If the type of data in the device read is defined in that device, it must be defined in the same way inSCADA so that the data read can be brought into the platform correctly. Essentially all variables, regardless of their type, are converted to the Double / Boolean type within the platform and are processed in those types within the platform.
After giving a brief description of Variable, let's examine the tools and features that the platform offers us through the screenshots provided.
In Figure 2, all the variables for the selected project are shown together with the timestamp and values. On the grid, we can monitor the properties of our variables and, if the communication channels are active, the actual values and time labels changing in real time.
Buttons in the upper right corner of our grid;
Export : Exports all variables in the Variable table in xlsx format.
Import : Imports the variable list prepared as xlsx to the Variable table.
Refresh : Displays the last values of the variables. Updates the data on the screen..
The values in the Variable grid are automatically updated. You can use the refresh command to update its values instantly before the update period.
Set : Allows the user to change the value of a selected variable on the grid. Opens the num-pad or on-off dialog according to the type of the variable and waits for the user to enter a value.
As shown in Figure 3, the data input dialog for changing the variable values, other than the Boolean/Digital type, opens.
For Boolean/Digital values, the dialog shown in Figure 4 opens.
Search : Allows to search on the grid.
As you can see in Figure 5, when we click the search button, we can search the grid according to the criteria on the form that opens.
Add : Allows to create a new variable.
Edit : Allows you to edit a selected variable on an existing grid.
Delete : Allows to delete a selected variable on an existing grid.
The form for creating or editing a variable in the inSCADA platform is shown in Figure 6. Using the form shown in the figure, let us know both the usage and the properties of the variables.
Specifies or defines the project to which the variable is linked or will be linked.
Specifies or defines the connection to which the variable is linked or will be linked.
Specifies or defines the device to which the variable is linked or will be linked.
Specifies or defines the frame to which the variable is linked or will be linked.
The short tag that identifies the variable. It can be used as P&ID number. It is also used as the column heading of variables in reports.
Refers to the word-index in the data block to which the variable is linked.
Specifies which type of data is read / written from/to the data block, to which the variable is linked. It also specifies how many bytes/bits/words to read from the start address. Data Types that you can select in inSCADA are listed below.
Float (32 Bit Single-Precision Floating Number)
Integer (32 Bit Signed Integer Number)
Byte (8 Bit)
Boolean (1 Bit)
Short (16 Bit Signed Integer Number)
Double (64 Bit Double-Precision Floating Point Number)
Long (64 Bit Signed Integer Number)
Defines the unit of our variable value. Used for illustration only. Does not affect the value, does not convert units. Used to specify the unit of values in reports.
Value Expression is used to perform unit conversions within inSCADA. It is a useful and flexible method.
The descriptive name of our variable value. Variable values can be accessed by this name.
Description about our variable value is entered.
Defines the number of decimal digits for our variable value.
Activates/deactivates the variable. Deactive variables are not updated.
Swaps the variable words. High Word-Low Word => Low Word-High Word
Swaps the variable bytes. High Byte-Low Byte => Low Byte->High Byte
Variable Expression allows variables to be processed with javascript while being read and written from/to the communication line in real time. In this way, variables read/written from/to devices can perform calculations, operations, and unit conversions within themselves without creating virtual variables or scripts.
Figure 8 shows how Variable Values are created in inSCADA.
Expression Type options;
Deactivates the Expression operation. In this case, Scale operation becomes active.
Activates Expression operation. Allows to write script in the Variable Add/Edit form.
Activates Expression operation. Enables the use of the desired expression from the Expression library.
Log Type determines the method by which variable values are saved to the database.
Ensures that the variable value is not saved in the database.
Allows the variable value to be saved on change to the database.
It allows the Variable Value to be saved for each scan period. Scan period for a variable is Device Scan Time * Frame Scan Time Factor. So, save period is Log Period * Device Scan Time * Frame Scan Time Factor.
It allows the Variable value to be saved when it exceed the given Threshold value percentage.
Expression is written in javascript to save the Variable value. When the result of Expression is true, the Variable value is saved to the database. The save period depends on the scan period.
Allows an Expression to be selected from the expression library to save the Variable value, and in case the Expression is true, the variable value is saved to the database. The save period depends on the scan period.
