Maple Systems OIT Family - Manual (Page 22)

Enhanced MRR Features
The following enhanced MRR features are only available on the OIT3100 and OIT4100
Series.
Bit vs Value
The default MRR is a “value” MRR. Which means that the PLC calls screens by placing
decimal or BCD numbers into the MRR. If you need the PLC to call a screen by setting a
bit instead of writing a number, you need to use a “bit position” MRR. When using a bit
position MRR, each bit in the specified MRR address corresponds to one of 16 stored
screens in the OIT. To determine which stored screen to display, the OIT examines each
bit in the MRR and then displays the stored screen that corresponds to the first set bit. For
directions on configuring a bit position MRR, refer to the MRR–Bit Position section in
CHAPTER 5: Displaying Stored Screens.
Multiple MRRs
Up to 40 MRRs can be created. For each bit position MRR, the PLC can request 16
different screens. With 40 bit position MRRs, the PLC can request all 500 OIT screens.
NOTE:Only one MRR is polled every 200 milliseconds. Therefore, if two MRRs are
configured, it takes 400 milliseconds to poll them.
Clear MRR After Each PLC Screen Request
When the OIT polls the MRR, it only displays a screen if the value in the MRR is
different from the last polled value. Therefore, if the PLC requests the same screen twice
without requesting a different screen between the two requests, the OIT does not
recognize the second screen request.
If your application requires that the PLC be able to request the same screen without using
an intervening screen, you should activate the Clear Register/Bit After Receiving Screen
Request option. When this option is enabled, the OIT sets the MRR to 0 after each PLC
screen request. For directions on configuring this option, refer to the MRR-Bit Position
section in CHAPTER 5: Displaying Stored Screens.
Clear MRRs During OIT Power Up
Each time the OIT powers up, the OIT can be configured to clear the MRRs or leave the
MRRs in their existing state. The default is to clear the MRRs. For directions on
configuring this option, refer to the MRR-Bit Position section in CHAPTER 5:
Displaying Stored Screens.
Multi-Language Support
This feature can be used to support control system applications in which multiple
languages are required. For example, suppose that you are creating a control system that
may be sold to companies with offices around the world. At the time of manufacture,
you may not know which part of the world the system will be eventually shipped to.
Without this feature, you would be forced to create multiple projects for the OIT, each a
different language. Then you would have to wait until the destination was known before
you could configure the OIT. The multi-language feature allows you to ‘split’ the 500
screens available in the OIT into 2, 5 or 10 separate groups or ‘languages’. Once
configured, you create the screens that pertain to that language. When the control system
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