UDT Inheritance

To Inherit Property Values from an Existing UDT

Let's use our data type Motor from the previous sections to create another data type. We'll set the parent to Motor so our new data type automatically inherits all the properties of Motor.

1. In the Tag Browser, click on the UDT Definitions tab and click the Add  icon to create a New Data Type. 
   The Tag Editor window will openon the.
   
   
   
   

2. In the Name field, enter name for your new UDT (i.e. Complex Motor). Under Parent Data Type property go to the dropdown and select the Motor data type and click Apply. Now your new Complex Motor UDT is inheriting from all the properties of the parent Motor UDT: Amps, HI SP and HOA.
   
   

   
   

3. With the Tag Editor still open, let's add an OPC Tag to the Complex Motor UDT. Click on the Add Tag  and select OPC Tag.
   
   
   

   
   

4.  Enter the following properties for your new Tag and click Apply. You will see the new Tag was added to the Complex Motor UDT. 
   
   Name: Temp
   Value Source: OPC
   Data Type: Integer
   OPC Server:  Click on the binding () icon and select Ignition OPC UA Server
   OPC Item Path: Browse the OPC and find the Tag you want to use. This example uses a Temperature Tag from a Sensor in the Dairy program. Click Commit.
   
   
   
   

   
   

5. In the image below the Temp Tag is pointing to a specific address in the PLC. Because we're creating a new Tag in our UDT, we don't want to point to one specific set of 'Temp' Tags. We want each instance of the Complex Motor UDT to reference a different set of 'Temp' Tags. To do that, we need to add a parameter to the Complex Motor data type that we will call 'SensorNumber'.
   
   
   

   
   

6. With the Complex Motor UDT Tag Editor open, let's create a new UDT parameter.  Right click the Edit  icon next to the Parameters property. The Parameters window will open.

7. Click the Add  icon and add the new parameter, 'SensorNumber' and click Commit. 
   
   
   
   

   
   

8. With the Tag Editor still open, select the "Temp' Tag.  In the OPC Item Path field, click the binding  icon, select Edit, and the Temp > OPC Item Path window will open. Place your cursor at the end of 'Sensor1', delete the '1', add a space, and enter '{SensorNumber}'.  Don't forget the curly braces. Click Commit to save your updates and go back to the previous window.  
   
   

   
   

   
   

9. In the Tag Editor window, click OK to save your UDT.  In the Tag Browser, the new data type is now visible in the , "Complex Motor."  You can see all the inherited Tags from the Motor data type and the newly added Temp Tag.
   
   
   
   

Creating the Data Type Instance

Now that our Complex Motor UDT is set up, let's create a data type instance of the Complex Motor.  

1. Click on the Tag tab, and from the context menu, select the Data Type Instance > Complex Motor.  
   
   
   
   
   

2. Enter the Name for the instance (i.e., Complex Motor 100). Click the Edit  icon next to the Parameters property and enter the parameter value of '2' for MotorNumber and SensorNumber, and press Commit. 
   
   
    

   
   

3. Click OK to create the instance. Now, you'll be able to see all the values for Complex Motor 100 including the Temp Tag that was added.  
   
   
   
   

UDT Inheritance Traits

UDT instances that are inherited and have properties that override the parent properties have a visual representation next to them.