Section 4:
Screen Triggering
Page 15
Assuming the 2800 has been successfully configured with both a Driver Firmware and an a Project it is ready for
normal operation. An appropriate communication cable must be connected between the 2800 and ULTRA Driver.
The communication cable is available from Quartech and is shown in Appendix A. When power is applied the
2800 will enter the normal Run Mode.
Upon power-up the 2800 will display two informational screens. The first will indicate the part number and serial
number of the unit. The second will indicate the firmware type, firmware version level, and other programmed
information such as interface type and baud rate.
Here is an example of what you will see:
During the time while the 2800 is displaying the above screens it will also be attempting to trigger the lowest
screen number contained in its memory. It does this by writing the screen number into screen trigger word one.
The 2800 incorporates dual screen trigger words which allows two screens to be displayed at the same time.
what exactly are screen trigger words?
The screen trigger words are two internal addresses that hold the number of the screen currently triggered. During
normal operation the 2800 will monitor these two words to determine what screens should be displayed. Writing a
screen number into either of these words will cause the 2800 to display the appropriate screen. There are three
ways that a screen number can be written to a screen trigger word.
!
The
Next
and
Prev
keys can write to a screen trigger word.
!
A function key can be configured to write to a trigger word.
!
A Data Set field can be configured to write to a trigger word.
But why use two trigger words?
The use of two triggers words is most effective when the trigger words are variable locations within the host
device, and the host device can write values into the triggers. This is not the case with the ULTRA 3000 driver,
however, some creative uses are possible.
When using more than one trigger word, care and planning is critical for success. Screen settings are important
when using two screen triggers because the settings can greatly affect the overall appearance of the 2800 display
when both triggers contain valid screen numbers.
Things to consider when using both screen trigger words.
When a screen is created using ScreenMaker 2000K several attributes will accompany the screen file. One of
these attributes determines the impact this screen will have on a screen being displayed from the other trigger
word. This attribute is the choice of one of three affects designated CLEAR, COVER, and OVERLAY.
CLEAR:
If the screen is configured as clear, the entire 2800 display will be cleared before this screen is
displayed. This allows only one screen to appear on the display even if another screen was
previously opened from the other trigger word. The screen triggered by the other trigger word is not
destroyed, only hidden. If this new screen is closed by writing a zero to the trigger word, the screen
triggered by the other trigger word will reappear. (Kind of like Windows!)
QUARTECH CORPORATION
2800 SERIES
UNIT SERIAL NUMBER
1234567890
ALLEN-BRADLEY
ULTRA 3000
Ver 3.00
RS-232 38400bps
PM2800U3K Revision 4
