Adding Buttons
and Switches
The next thing to do is to add
some buttons and switches to
control our meters.
For example, the meter scale
now reads 0 to 250, but maybe
our plot area’s Y scale is set at 0 to
1,000. Let’s add a momentary
pushbutton below each meter to
adjust the meter scale to the Y axis
scale. This is done by selecting one
of the Momentary Image Button
icons and dragging it under the
meter. Then, label it “Y Axis Adj.”
When you click on this button, it
will set the meter scale to the Y
axis (Figure 7).
Recall that both of these
meters have alarm settings and if
the alarms are exceeded on either
the high or low end, the meters
will “beep” or sound whatever
audio alarm you select for each of
them. To mute the audio tones,
we’ll add a slider switch to each meter so when the switch
is ON, the tone will sound. When it’s OFF, it won’t. It’s
basically the same procedure: Left-click on the slider
switch and drag it under the meter,
then position it with the keyboard
arrow keys like the Y axis switches
(Figure 8).
We’ve adjusted each meter to
monitor a single analog channel,
with the top meter set to analog
Channel 1 and the bottom meter
set to analog Channel 0. Now,
when we begin plotting analog
data again, these meters will
display the levels of the analog
signals.
Well, so much for analog
signals. How about digital?
LEDs and More
For monitoring individual
digital signals, LEDs are usually the
choice. While MakerPlot is capable
of displaying up to 32 separate
digital signals, this example is
limited to eight LEDs. Using the
Object Editor again, we’ve clicked on and dragged a
single red LED and placed it above the top meter. Then,
we used the Duplicate button to create seven more.
May 2014 57
Figure 8. Adding meter alarm switches.
Figure 9. Adding LEDs.
