5.2 Using the Image Change Drawing Method

Because the value of a digital input tag changes from "0" to "1" according to the signals incoming from the equipment, it is a good idea to pick a drawing method that clearly imparts that the booster pump is either running or stopped.

In this exercise, you will use the Image Change drawing method to display a single graphic whose indicator area will change color according to the value of the tag. Again, you use the Tag Browser's Draw button to access the drawing methods available to a tag according to its tag type. The Tag Browser should still be open, and the new digital input tag should be selected.

 

1.  Click the Draw button.

The Digital Input dialog opens and displays the drawing methods for digital input tags. (The color swatches may initially be red on your screen depending on whether the current pump status is ON or OFF.)

Figure 51

 

2.  Click the Image Change button. A rectangle will appear attached to the pointer. Place this on the screen to the left of the tank, about one tank-width away.

3.  The Image Change Graphic Editor opens.

You will use the Graphic Editor dialog to configure the behavior and appearance of the Image Change object.

Figure 52

The Image Change Graphic Editor dialog consists of a series of buttons that enable you to select colors according to the value of the tag, and a series of buttons that enable you to select different graphics to display according to the value of the tag.

 

In this exercise, we want to use the Image Change Graphic Editor to display a single bitmap whose indicator area changes color according to the value of the tag.

4.  Select the "Use State 0 Bitmap For All States" checkbox.

This configures the Image Change object to use a single bitmap for all values of the tag.

5.  Click the State 0 Bitmap button.

The Select Bitmap dialog opens and displays the available groups of graphics.

Figure 53

6.  Scroll down to find, then click the Pumps group button.

The Select Bitmap dialog changes to display the available pump graphics.

7.  Scroll down, then click on "Pump02".

The Select Bitmap dialog closes and the newly selected pump bitmap displays in the Image Change dialog. The Image Change dialog should appear similar to Figure 54.

Figure 54

The default state colors displayed on the Image Change dialog are the same as those we chose in our system plan: red for a value of State "0" (false or a stopped state), and green for a value of State "1" (true or a running state).

 

8.  Click the OK button.

9.  If the Tag Browser is obscuring your view of the new pump object, click and drag its title bar to move it.

10. If necessary, re-position and re-size the pump bitmap approximately 1 inch to the left of the booster tank with its base slightly above that of the tank as shown in Figure 55.

Figure 55

 

The simulated values for "DI10_1 Booster Pump Status" are now represented on the Booster Station application page. As the simulator runs, the colored indicator at the base of the booster pump graphic will change color from red to green, indicating whether the booster pump is on or off.

 

Note that the center of the pump bitmap is marked with a question mark, indicating questionable data.