5.3 Copying a Tag and its Properties

The next step is to build the next digital input tag to represent the process information for the compressor. As per our Tag Table (see Create a Tag Table), the "Compressor Status" digital input tag will be named DI30_1.

 

The compressor and the booster pump have process information that is very similar. Both indicate whether they are running or stopped by sending a signal of "1" or "0" respectively to the PLC. Because the two digital tags are almost identically configured, we can use the copy function of the Tag Browser to speed the process of developing the tags for our application.

 

When a tag is copied, all the properties of the tag, with the exception of its name, are filled into a new tag properties folder. Simply enter a new name for the tag and adjust any of the properties that require modification, and your tag is complete. This process is useful in situations where you have a series of similar tags.

 

The Tag Browser should still be open from the last exercise, the Types drop-down list should still have Digital Input selected, and the tag list should be filtered to display the newly created digital input tag DI10_1. (If the Tag Browser has been closed, open it now.)

 

1.  Ensure that DI10_1 is selected (it should be highlighted in blue).

2.  Click the Copy button. A new digital input tag properties folder opens and displays the identification properties of its ID tab.

Figure 56

Examine the new digital input tag properties folder. Note that the contents of the Area and Description fields have been copied from the first digital input tag DI10_1.

 

3.  Enter "DI30_1" in the Name field (as per our Tag Table. See: Create a Tag Table) and press the Enter key.

4.  Modify the description to read "Compressor Status" in the Description field and press the Enter key.

5.  Click the I/O tab to open it.

 

Notice that all of the properties that were configured for DI10_1 have been copied to the new digital input tag properties folder. The Bit 0 Address property will need to be changed since the compressor has a different address on the PLC.

 

6.  Enter "5" in the Bit 0 Address field and press the Enter key.

This digital input tag is a single bit tag, and requires no further configuration. The completed I/O tab should look like Figure 57.

Figure 57

7.  Click the OK button. The new digital input tag "DI30_1 Compressor Status" is added to the Tag Browser.