15
discussed earlier, the default duration for Time ON and (in On/Off mode) Time OFF is 0.000
seconds. This means that as soon as the data in Field 1 is displayed, it is immediately replaced with
the data from the next available field, which in this message is Field 2. As soon as the data in Field
2 is displayed, it also is immediately replaced with data from the next available field. As no
subsequent fields contain data, the data from Field 1 is displayed and the cycle begins again. With
these default settings, the message is useless. Therefore the operator must alter the duration times, a
process covered in the next exercise.
EXERCISE IV: Message Timing
Continuous Mode...
As demonstrated in Exercise III, when certain effects are applied to data, other default settings
must be changed in order to make the message legible. In the case of the test message, applying the
Bold effect has necessitated a change in the default duration setting.
1. Open the TEST.MSG Message File.
2. Highlight the “Caution Ahead” message and click on the “Edit” button. This will open the mes-
sage editing screen.
3. Set the mode selection button to “Continuous”.
4. Click on the Functional Effects button in front of Data Field 1. This will open the Segment
Scrolling Parameters window for Field 1.
5. In the “Time ON” section, increase the setting from 0.000 seconds to 0.693 seconds by using
either of the two “increase” or “up” arrows. The single arrow increases duration in increments
of approximately 0.017 seconds. The double arrow increases duration in increments of approx-
imately 0.173; roughly the equivalent of 10 clicks on the single arrow.
6. After setting the “Time ON” duration to 0.693 seconds, click “OK” to close this window.
7. Click the “OK” button to close the message editing screen.
8. Click the “Display” button in the Main Programming Window.
As you will see, the word “CAUTION” is displayed for 0.693 seconds, but the word “AHEAD” is
flashed on the display for such a brief period, it is perceived as just a flash of characters. This
situation is remedied by increasing the duration for Data Field 2 in the exact same manner as
applied to Data Field 1. Follow steps 4 through 8 as outlined above, only apply them to Data Field
2. After step 8, the message should appear as follows:
“CAUTION” is displayed for 0.693 seconds
“AHEAD” replaces “CAUTION” and is displayed for 0.693 seconds
At this point the display goes blank for a brief period and the cycle begins again with Data Field 1.
The blank period between the last used Data Field and Data Field 1, is equal in length to the “Time
ON” setting for the last used Data Field. In this case, 0.693 seconds. This only applies when the
message display is in “Continuous” mode. The following section will outline timing characteristics
in “On-Off” mode.
On-Off Mode...
In the previous section, the impact that “Continuous” mode has on timing events was outlined.
