Mitsubishi Electric EMU4-CNT-MB User Manual page 81

<Example of action when the pressure value is both above the upper limit value and below the lower limit value>
<Example of action>
Adjustment operation time: 1 minute
Start delay time:
Control target at
59 min
the start of control
Upper-upper
limit value
Upper limit
value
Lower limit
value
Lower-lower
Priority limit value
High
Compressor 1
Operation (load)
Compressor 2
Operation (load)
Compressor 3
Operation (load)
Compressor 4
Operation (load)
Low
①A pressure value exceeds the upper-upper limit value. At the next control period (01 min), the compressor 1 will be switched to
the stop mode regardless of the adjustment operation time.
In addition, the compressor 2 with the next highest priority will be switched to the unloaded operating mode.
②The compressor 1 and compressor 2 are switched to the stop mode and unloaded operating mode respectively.
③Since the adjustment operation time is over, the compressor 2 is switched to the stop mode.
The compressor 3 with the highest priority in compressors with the loaded operating mode is targeted and switched to the
unloaded operating mode.
④Since the adjustment operation time is over, the compressor 3 is switched to the stop mode.
Since the pressure value drops below the lower-lower limit value, at the next control period (04 min), the compressor 1 will be
switched to the loaded operating mode regardless of the adjustment operation time and start delay time.
⑤Regardless of the adjustment operation time and start delay time, the compressor 1 is switched to the loaded operating mode.
The compressor 2 with the highest priority in compressors with the stop mode is targeted and it keeps standby mode until the
adjustment operation time is over.
⑥Since the pressure value rises to the lower limit value or more, at the next control period (06 min), the control for compressor 2
will not be executed.
Furthermore, since the pressure value exceeds the upper limit value, at the next control period (06 min), the compressor 4 with
the highest priority will be switched to the unloaded operating mode.
⑦The compressor 4 is switched to the unloaded operating mode.
1 minute
00 min 01 min 02 min
Pressure measured value
Stop
Operation (unload)
②
①
03 min 04 min
Stop
Operation (unload) Stop
④ ⑤
③
80
Adjustment operation time
Start delay time
Measurement value for
determination
05 min 06 min
Operation (load)
Operation (unload)
⑥
⑦