Connecting the frequency converter for operation with two pumps and a manual switching algorithm "Working - Standby"
Wiring diagram:
For the effective operation of the frequency converter, it is important to perform preliminary settings according to the instructions provided with the initial parameterization, as well as to ensure that the parameters are aligned with the characteristics of the motors.
Required parameters
Additionally, the following parameters should be set:
Parameter table for circulation pumps
| Parameter code | Parameter name | Parameter value |
| 3-02 | Min setting | [0] min working level or min level signal from the sensor (see sensor marking) |
| 3-03 | Max setting | [10] max working level or max level signal from the sensor (see sensor marking) |
| 3-15 | Task source 1 | [0] No function – not used, otherwise the speed setting will be the sum of the tasks from sources 3-10, 3-15, and 3-16 |
| 3-16* | Task source 2 | [0] No function – not used, otherwise the speed setting will be the sum of the tasks from sources 3-10, 3-15, and 3-16 |
| 5-12* | Function of digital input terminal 27 for VLT HVAC Basic | [0] No function – not used (otherwise, under factory settings, the function is run inverse) |
| 5-400 | Relay function 1 | [6] Running no warning – drive stopped or in fault (using inverse (normally closed) contact) |
| 1-00* | Configuration mode | [3] Process – PI controller mode |
| 6-12 | Terminal 53 high signal | [20] mA – high range for analog input 1 |
| 6-14 | Terminal 53 low setting | [0] – low setting for analog input 1 |
| 6-15* | Terminal 53 high setting | [10] – high setting for analog input 1 |
| 7-20* | OS source for PI control (for VLT Micro Drive) | [1] Analog input 53 – analog input 1 terminal 53 |
| 7-30 | Normal/inverse operation mode of controller (for VLT Micro Drive) | [0] normal (mechanism speed is higher with a + error) [1] inverse (mechanism speed is lower with a + error) |
| 7-33* | Proportional coefficient PI regulation (for VLT Micro Drive) | [1] – adjustable for use |
| 7-34* | Integral coefficient PI regulation (for VLT Micro Drive) | [8] – adjustable for use |
| 20-00* | OS source for PI control (for VLT HVAC Basic) | [1] Analog input 53 – analog input 1 terminal 53 |
| 20-81 | Normal/inverse operation mode of controller (for VLT HVAC Basic) | [0] normal (mechanism speed is higher with a + error) [1] inverse (mechanism speed is lower with a + error) |
| 20-93* | Proportional coefficient PI regulation (for VLT HVAC Basic) | [1] – adjustable for use |
| 20-94* | Integral coefficient PI regulation (for VLT HVAC Basic) | [8] – adjustable for use |
Configuring PI controller coefficients
- Set 7-34 = 9999, 7-33 = 0.3. Gradually increase the value of 7-33 until the appearance of auto oscillations.
- Reduce the value of 7-33 by 40% and lock it.
- When the value of 7-33 is found, set 7-34 = 20 and decrease it until the appearance of oscillations or significant overshoot.
- Increase the value of 7-34 by 25% and lock it.