11.8 Using the Numeric Entry Tag Drawing Method to Enable Operators to Input a Feed Time

The final tag to be drawn on the Chlorination Unit application page is "AO40_1 Feed Time" for the dry chemical feeder.

According to the system plan, the operators of the system require a means to enter numeric values representing the feed time for the dry chemical feeder.

 

There are two analog output tag drawing methods that allow the input of analog data: these are the Numeric Entry drawing method and the Slider drawing method. Because we wish to enter precise numbers, the Numeric Entry drawing method is a good choice for "AO40_1 Feed Time".

 

1.  Open the tag browser if it is not currently open.

2.  Select Analog Output from the Types drop-down list. The Tag Browser displays the available analog output tags.

3.  Select "AO40_1 Feed Time" from the list of tags.

4.  Click the Draw button. The Analog Output dialog opens and displays the wide variety of analog output tag drawing methods. (Figure 151)

Figure 151

The first six drawing methods (Numeric Entry, Slider, Set Analog Value, Droplist Control, Set Value Btn, and Set Value Hotbox) are the only ones that enable operators to output analog values to the PLC and related equipment. The remaining analog output tag drawing methods are the same as those for analog input tags.

The intent of these drawing methods is to display the value of the analog output tag both before and after the operator has sent data to the tag. Because the Numeric Entry drawing method will provide the most accurate means of specifying the feed time, you will use it to draw "AO40_1 Feed Time".

 

5.  Click the Numeric Entry button.  A sample numeric entry box will attach itself to the cursor. Place this on the page above and to the left of the Water Valve as shown in Figure 152:

Figure 152

6.  The Numeric Entry graphic editor dialog opens.

Figure 153

7.  Select "0" from the Number Of Decimal Places spin box.

Operators will be entering seconds as the feed time for the dry chemical feeder therefore you do not require fractions of a second.

 

8.  Enter "Feed Time" in the Title field.

The remaining properties of the Numeric Entry Style dialog do not require modification.

9.  Click the OK button.

10. Close the Tag Browser.

11. Click the "No Tool" button to place the application in operation mode.

The equipment on the Chlorination Unit application page should appear similar to Figure 154 (when in operation mode).

Figure 154

 

To set the feed time for the dry chemical feeder, enter the desired time value between 5 and 20 seconds and click the Enter key on your keyboard. The data is sent to the virtual controller.

If you enter a value lower than 5 or higher than 20, the following message appears (Figure 155).

Figure 155

To remedy the situation, click the Close button on the dialog and enter a new value between 5 and 20.

The Chlorination Unit requires only one remaining element and it is complete; a page hotbox to the left of the page to enable operators to open the Booster Station application page and view the overall system.

Complete the On Your Own section that follows to finish the Chlorination Unit application page.