Mitsubishi Electric MELSEC iQ-R Series User Manual page 34

Section 3 NAME AND FUNCTION OF EACH PART
(4) How to reset Alarm flag
When Alarm flag is ON during the alarm occurrence or the self-retention (in the case of the alarm reset
method = "Self-retention"), Alarm flag can be reset (turned OFF) using Alarm reset request.
(a) How to reset Alarm flag during alarm occurrence (example of the upper limit alarm monitoring with the
alarm 1)
(i) If the measured value that was set with the alarm 1 monitoring factor exceeds the upper limit, Alarm
1 flag (XnA) will turn ON.
At the same time, ALM1 LED flashes.
(ii) By turning Alarm 1 reset request (YnA) to ON, Alarm 1 flag (XnA) will turn OFF.
At this time, ALM1 LED will remain flashing (because ALM1 LED is synchronized with the alarm
status, it will not turn off).
(iii) Check that Alarm 1 flag (XnA) becomes OFF, and then set Alarm 1 reset request (YnA) to OFF.
(iv) If the measured value goes below the upper limit, ALM1 LED will turn off.
(v) After that, if the measured value exceeds the upper limit, Alarm 1 flag (XnA) will turn ON again. At
the same time, ALM1 LED flashes.
Alarm 1 flag (XnA)
Alarm 1 reset request (YnA)
Figure 3.4.4-5 Procedure for resetting Alarm 1 flag (alarm reset method = "Self-reset")
(b) How to reset Alarm flag during self-retention (only in the case the alarm reset method = "Self-retention")
Refer to the procedure described in (3)(a).
(5) Precautions during the alarm monitoring
When current demand time and electric power demand time are set to anytime other than 0 second, current
demand value and electric power demand value become lower than the actual values (closer to 0)
immediately after the power source ON and the CPU reset.
When current demand value and electric power demand value are being monitored for their lower limit alarm,
the alarm occurrence flag may turn ON. Thus, to avoid this, follow the procedure below.
(a) Set the alarm monitoring target to "no monitoring" immediately after the power source ON and the CPU
reset.
(b) After passing for a 3-times longer period than the demand time, set the alarm monitoring target again,
and start the alarm monitoring.
Upper limit
Alarm
delay time
ON
ALM1 LED OFF
(i)
ON
OFF
Flashing OFF
(ii) (iii) (iv)
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Alarm
delay time
ON
Flashing
(v)