Service manual

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123
+24V
COM
Y
Z1 Z2
A B
B A
X1 X2
+24V
COM
ENC constant pressure water supply board
Fig.10-7 connection between water supply controller and inverter
Explanation for terminals: A, B terminals of constant pressure water supply
board are for RS485 receving and sending, Z1 is over pressure signal output
terminal when pump increased, Z2 is pressure falling signal output terminal when
pump reduced, Y is fire fighting pump control signal input terminal, +24V, COM
are respectively power supply input terminal and grounding terminal of the board.
10.6.4 Constant pressure water supply control and its mode
(1) Variable frequency/
bypass run and switch
Variable frequency run means that the motor is controlled by inverter output
frequency. Bypass run means that the motor is connected to power source directly.
Variable frequency/ bypass switch means process from inverter drive to power
source drive or from power source drive to inverter drive.
(2) Operation mode
a. frequency conversion repetition mode
Inverter drives pump to run at variable frequencies, it can determine running
pump quantity (within set range) according to pressure closed loop control
requirement and only one pump can be drived by variable frequency at one
time.Repetition mode of pump drived by the inverter is as 1—2—3—4—1—2—3
— 4—1, first-on first-off principle obeyed when the system reduces pump
quantity.
b. frequency conversion fixed mode
The inverter drives one fixed pump, while at least one of the other three pumps
has to be selected. Pump adding is according to repetition mode while pump
reducing is according to the order of first-on first-off or first-on last-off.
c. shutdown mode
In the mode of a or b, all pumps stop running if the inverter is shutdown.
(3) Explanation for parameter selection of operation mode
a. frequency conversion repetition mode