KEP MMI-1 Series, Инструкции по эксплуатации и монтажу

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3.0 MMI Operations
Once the MMI is programmed and connected to the PLC, normal operation begins. The MMI
establishes communications with the PLC. It then requests the number in the Message Triggering
Register (MTR) and displays the corresponding message.
3.1 The Message Queue
Occasionally messages are called up faster than they can be displayed. When this happens
messages are held in a Queue and wait their turn to be displayed. The message Queue holds up to 5
message numbers.
3.1.1 Queue Activation Messages are stored in the Queue when:
1 A series of Chained messages are being displayed.
2 A message with a long minimum display time is displayed.
3 A message with a long scrolling time is displayed.
3.1.2 Queue Action
The Queue is emptied on a first in first out basis. If the Queue is full, additional messages will be lost.
Warning Function keys that have displayable message text assigned to them clear
the Queue.
3.1.3 The Interrupt Message
Message number 255 is the Interrupt message. When message 255 is called the Queue is
immediately cleared. The next message number that appears in the message triggering register is
then displayed.
An example of Queue operations:
Message 62 is being displayed with a minimum time of 10 seconds.
Display Queue
23 —
During that period message numbers 34, 15 and then 211 are called for by the MTR.
Display Queue
23 34
15
211
The MMI will put message 34, 15 and 211 in the Queue. When message 23 has timed out, message
34 will be called up and displayed.