Expand the RSLogix 5000 Controller Organizer tab, find and expand the Data Types folder, and select the User-Defined node.

Right-click on the User-Defined node and select New Data Type….

The Data Type window that appears will allow us to configure our UDT. Enter the following name and description in the fields provided:

The data table under the Description UDT allows us to define the tags that will be included with each instance of the structure we've created. If we had created this UDT earlier, it would have saved us quite a bit of work creating all the tags for our various flow control valves (FC1001, FC1002, FC1003, and so on). Let's add our first tag to the table to replace our flow control valve position feedback variable FC1001_PV. Add the following values to the first row of the table:

Next, we can enter the remaining simple base types to the table as follows:

UDTs also allow us to create more complex base types inside them, such as the TIMER type and even other UDTs. Let's add the complex base type tags to our UDT TON: TIMER as shown in the following screenshot:

Click on OK to save our UDT. Now we have recreated all of our flow control valve tags in a single UDT.

Next, we will create an instance of our VALVE UDT and link it to our Analog In card channel. On Controller Organizer, right-click on Controller Tags under the Controller folder and select New Tag… (or press Ctrl + W).

In the New Tag window, enter the following values:

Click on the OK button to save the new tag.

Next, we will link one of the values of our UDT tag using Ladder Logic. Open the VALVES Ladder Logic Routine and add a new rung by right-clicking and selecting Add Rung (or press Ctrl + R).

Add a Move element to the new rung by selecting it under the Move/Logical element group.

Set the source of the element to FC1001_PV and set the destination of the element to FC1001.PV as shown in the following screenshot: