Mitsubishi Electric MELSEC FX Series User Manual page 69

FX -4LC User's Manual
3U
Caution
• The loop breaking alarm function judges abnormalities in the control loop, but cannot detect positions in
which abnormalities occur. Check each part of the control system in turn.
• When the AT (auto tuning) function is completed, the loop breaking alarm judgement time is automatically
set to the integral time result multiplied by 2.
• Set the time in which the measured increments changes by 2.0 C or 0.2% of the span or longer as the loop
breaking alarm judgment time.
If the loop breaking alarm judgement time is too short or is not suitable to control targets, the loop breaking
alarm may repeatedly turn on and off or may not turn ON. In such a case, change the loop breaking alarm
judgement time in accordance with the situation.
• In heating/cooling PID control, the loop breaking alarm function is disabled.
• While AT (auto tuning) is performed, the loop breaking alarm function is disabled.
• When the set value is "0", the loop breaking alarm function is disabled.
• When the measured value (PV) is within the loop breaking alarm dead zone, alarm is not issued even if the
alarm issue condition is satisfied.
• In heating/cooling PID control, the loop breaking alarm dead zone is invalid.
6 Introduction of Functions
6.12 Loop Breaking Alarm Function (LBA)
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