Maple Systems OIT Family - Manual (Page 70)

Standard Mode
In Standard mode, screens requested by the PLC or OIT enter the stack only after being
displayed. When an alarm screen is displayed, all non-alarm screen requests are ignored;
they are not displayed or stored in the stack. When the stack contains 10 screens, adding
another screen causes the oldest screen to fall out of the stack.
When the OIT operator presses the LAST MSG key, the most recent screen in the stack is
redisplayed. Pressing the LAST MSG key again, redisplays the next oldest screen in the
stack. When the OIT operator presses the NEXT MSG key:
• If a screen from the stack is currently being redisplayed, the next newest screen in the stack
is redisplayed.
• Otherwise, nothing happens.
If the stack contains a screen that is part of a chain, the OIT operator can use the PAGE
DOWN and PAGE UP keys to view the other screens in the chain.
NOTE:The LAST MESSAGE, NEXT MESSAGE, and PAGE UP keys are not available on the
OIT3160 or OIT4160.
To configure the screen stack for Standard mode:
1. From the Configuration menu, choose Message Control Settings. The OIT Message
Control Settings dialog box appears.
2. In the Message Request Register group box, make sure the Enable Message Stack
group box is not selected.
3. Choose the Done button to return to the OITware-200 main screen.
Stacked Mode
In Stacked mode, screens requested by the PLC are sent directly to the stack. The OIT
operator must press the NEXT MSG key to display them. This ensures that the OIT
operator has enough time to read each screen. However, screens requested by the OIT
(except timer event screens) still operate the same as in Standard mode.
If an alarm screen is displayed when the PLC requests a non-alarm screen, the non-alarm
screen is sent directly to the stack, where it can be displayed by the OIT operator after the
alarm is acknowledged. In this situation, non-alarm screens requested by the OIT (except
timer event screens) are still ignored; they are not displayed or stored in the stack.
The stack only holds 10 screens; this includes historical screens and screens waiting to be
displayed. Adding an 11th screen causes the oldest historical screen to fall out of the stack. If there
are no historical screens, then the oldest screen waiting to be displayed falls out of the stack.
When the OIT operator presses the LAST MSG key, the most recent historical screen in
the stack is redisplayed. Pressing the LAST MSG key again, redisplays the next oldest
historical screen in the stack. When the OIT operator presses the NEXT MSG key:
• If there are any screens waiting to be displayed, the oldest one is displayed.
• If there are no screens waiting to be displayed and a historical screen is currently being
redisplayed, the next newest historical screen in the stack is redisplayed.
If the stack contains a screen that is part of a chain, the OIT operator can use the PAGE
DOWN and PAGE UP keys to view the other screens in the chain.
NOTE:The LAST MESSAGE, NEXT MESSAGE, and PAGE UP keys are not available on the
OIT3160 or OIT4160.
Displaying Stored Screens 70
1010-0099, Rev. 07