Mitsubishi Electric MELSEC-Q QE81WH4W User Manual page 31

4 Functions
3) An example of the alarm 1 was indicated in 1) and 2) above. The alarm 2 will be in
accordance with the same behavior.
For the setting items for the buffer memory that corresponds to the alarm 2 and the I/O
signals, refer to Chapters 5 and 6. The following describes a case with the alarm 2.
[When the alarm reset method is in the "auto reset" setting (Example of a lower limit monitoring
at alarm 2)]
(a) If the measured value that was set with the alarm 2 item goes below the lower limit and the
situation continues and remains for the alarm 2 delay time, Alarm 2 flag (XnB) will turn ON.
At the same time, ALM2 LED flashes.
(b) If the measured value exceeds the lower limit, Alarm 2 flag (XnB) will turn OFF. At this
time, ALM2 LED is turned off.
(c) If the measured value that was set with the alarm 2 monitoring item goes below the lower
limit but exceeds the lower limit within the alarm 2 delay time, then Alarm 2 flag (XnB) will
remain in the OFF status.
Alarm 2 flag (XnB)
Figure 4.2.4-4 Time chart of the upper/lower limit alarm (alarm reset method = "auto-reset")
Lower limit
Alarm delay time
OFF
Flashing
Alarm delay time
OFF
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QE81WH4W