How to Create an Object Simulating Data

system:inmation comes equipped with a number of objects that can be created and configured to suit different purposes. One of these is a Generic Item and it can be set up and used in different ways. For instance, generating numerical data through predefined algorithms and programmed Lua scripts. It can also return textual data including dates and arrays of all data types.

In this example we will create a Generic Item that returns simulated numerical data. Creating objects in the I/O model requires administrator privileges so first log in as an administrator.

You also need to create a Connector object or use an already existing Connector, see How To Add a Connector for more information.

Right click on the Connector to open the Context menu and select Admin > New > Data Processing > Generic Item to bring up the Create Object wizard

Figure 1. New Generic Item - Context Menu

In the Common settings of the Create Generic Item wizard, fill out the fields as shown below (only the Object Name field is mandatory). The System Alias is a unique identifier for the item that will be shown by the system OPC Server namespace as a shortcut to the item.The Display Alias is the name that will be used in displays for a more readable name. The Engineering Unit is the unit of measurement that will be attached to the data value generated. The Decimal Places property determines how many decimal places should be used for this object in displays. The Generation Period determines how often the item should generate a new value.
Click Next to continue

Figure 2. Create Generic Item Common Settings

In the Limit Settings, set the limits to the desired engineering unit range of the item and add Low and High Limit values (used for alarming). Click Next

Figure 3. Create Generic Item - Limit Settings

The next step allows the generation type to be chosen, and the functions and paramaters of data generation to be configured. The dropdown box at the top shows the various types available. The parameters displayed here depend on th Generation Type selected. For this example we will use the default Numeric Value Generator
This type comes with different Functions to generate data. Selecte the Sawtooth values function. The Function Period determines in what timespan the function should change its value from Minimum to Maximum and back to Minimum again. Set the values as shown below, which will result in a sawtooth signal that will repeat itself every 10 seconds. The last 3 options allow arrays of values to be produced, leave them as default and click Next

Figure 4. Create Generic Item - Generation Type

The Archive Options determine if the data of the this Generic Item object should be archived. In the Archive Selection select the Test Archive option, indicating that the data will be stored in a different repository section than actual production data. The Value Storage Strategy can be set to store the raw data or an aggregate of the raw data. You can also select the Persistency Mode and the Persistency Timeout options, as is shown below. The last few steps of the wizard can be skipped in this example so click Create to create thew object in the I/O model tree.

Figure 5. Create Generic Item - Archive Options

Select the newly created item and either drag and drop to a Realtime Trend display or use the item context menu to add to a Realtime Trend display (shortcut Alt+T). You can now view the visulaized simulation data as it is processed by the Generic Item.

Figure 6. Simulated Realtime Data from Generic Item

TIP:*Training Task: Create Another Generic Item* Add another Generic Item to the I/O Model tree. Select a different Generation Type and change the parameters. Where in the tree can these items be created? Does it make a difference where they exist?