8.2 Adding a Digital Output Tag to Control the Booster Pump's Mode

 

The next step is to configure the digital output tag that places the pump into auto mode if it has been switched to manual mode.

The Tag Browser should still be open from the last exercise; if you've closed it, re-open it.

 

1.  Select Digital Output from the Types drop-down list.

Because no digital output tags have been configured for this application yet, the tag list appears empty.

2.  Click the New button. The new digital output tag properties folder opens and displays the usual ID tab.

3.  Enter "DO10_3" in the Name field and press Enter.

4.  Select "Tank" in the Area drop-down list.

5.  Enter "Booster Pump Auto" in the Description field and press Enter.

The completed properties of the ID tab look like Figure 96.

Figure 96

6.  Click the I/O tab to open it.

7.  Click the tag button to the right of the I/O Device field.

 The Tag Browser opens. The "Modbus 1 Virtual Modicon PLC" tag is selected in the tag list, being the only available option.

8.  Click the Select button.

The "Modbus1" tag appears in the new digital output tag's I/O Device field.

9.  Enter "3" in the Address field. The completed I/O tab should look like Figure 97.

Figure 97

The remaining fields of the I/O tab are not required for this digital output tag. The Pulse Duration field is intended for pulsed outputs. The Pulse Duration for the "Booster Pump Auto" digital output tag will be left blank to ensure that it provides a maintained signal. The Data Source drop-down list enables you to select another tag whose value would then become the value of this tag. The Invert Output and Invert Data Source checkboxes are used to reverse signals. Further information on these fields and the remaining tabs of the digital output tag properties folder can be found in the VTS Developer's Guide.

 

10. Click the OK button. The tag properties folder closes and the new digital output tag appears in the Tag Browser.

Now that you are familiar with the creation of digital output tags, try to complete the On Your Own section that follows.