Fuji Electric FRENIC-AQUA series, User Manual

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Mutual operation control (Communications-linked inverter drive motor floating system)
This system controls up to three pumps which are individually connected with the FRENIC-AQUA
units in multidrop connection via RS-485.
The FRENIC-AQUA specified as a master performs PID control and sends run commands and
frequency commands to other two slaves.
If the frequency rises due to a PV signal level drop to satisfy the pump adding conditions, the second
inverter is started. After the start of a total of three inverters, the master can output a start signal to
drive an auxiliary pump. The start/stop sequence of pumps cycles.
Even if the master stops due to an alarm, the slaves can continue running.
The advantage of this system is very small pressure fluctuation at the time of adding/subtracting
pumps and small load to piping since all pumps are driven by inverters. The disadvantage is high cost
since each pump requires an inverter.
Mutual operation control (Communications-linked all motors simultaneous PID control
system)
This system is configured in the same way as the communications-link inverter drive motor floating
system except that all motors are driven under PID control with the same frequency at the same time.
Even if an alarm occurs, the remaining inverters continue to run. If the pressure is insufficient, the
inverter outputs a start signal to an auxiliary pump to add one pump.
The advantage of this system is that driving two or more pumps under PID control at the same time can
deliver water with low power for optimum watt hour in the cooling water cycling system managing the
flowrate.
< Maximum number connection configuration of mutual operation (J401 = 52 or 54) >
L1/R
L2/S
L3/T U
V
W
Acc./Dec.
controller
PID
Command
M0
Pump
Pressure sensor
Feedback
L1/R
L2/S
L3/T U
V
W
Acc./Dec.
controller
Command
M0
Pump
L1/R
L2/S
L3/T U
V
W
Acc./Dec.
controller
Command
M0
Pump
RTU communication
PID
control
DX+/DX-
DX+/DX-
DX+/DX-