Constant Pressure Water Supply
Kinda VFD applied in constant water supply system (PID control)
1, Load feature
(1) PID function is required.
(2) There is a pressure sensor in the system.
(3) In theory, if the running frequency is H1, then
Energy Saving = 1-(H1/50)3.
2, Requests for frequency inverters (VFD)
(1) Soft start the motor, reduce the surge current.
(2) PID control should be stable and accurate.
.3, Typical wiring diagram
4, Parameters setting list
| No. | Function codes | Default | Setting value | Explanation |
| 1 | F0-02 | 0 | 1 | Start / stop by external signal (If necessary) |
| 2 | F0-03 | 1 | 8 | PID control |
| 3 | F9-00 | 0 | 0 | PID target value set by F9-01 |
| 4 | F9-01 | 50% | -- | Set suitable value depend on system |
| 5 | F9-02 | 0 | 0, 1, 2 | Pressure feedback channel (AI1, AI2 or AI3) |
| 6 | F9-08 | 2.00Hz | 0.00 | Cutoff frequency of PID reverse |
| 7 | F8-48 ~ F8-52 | -- | -- | Set suitable dormancy and wake up parameters. |
5, Notices
(1) select a suitable pressure sensor, the calculation of F9-01 as below
if the pressure sensor measure range is 16bar (1.6Mpa), and the
target pressure is 5bar (0.5Mpa), then F9-01=5/16*100%=31.3%.
(2) Maintenance regularly, pay attention to dust and humidity prevention.