Danfoss vlt aqua, Manual, Page: 32 / 48

Verifying Operation
9
Press the “Auto On” button at the bottom of the keypad.
9
Close the switch wired to DI 27 and reset the alarm if necessary
9
With the remaining switches off, the display status word reads “auto remote standby”
9
Start the drive with S1 (DI18) and modulate the feedback above and below the set-
point. The drive should respond to the change in feedback. When the feedback falls
below the set-point, the drive should speed up to compensate. When the feedback
goes above the set-point, the drive should slow down. When the feedback and set-
point match, the drive runs at a constant speed between 20 and 60 Hz. Notice that the
drive will only slow to 20 Hz. This is because the minimum speed is set to 20 Hz in
parameter 4-12.
9
The LED on the switch box is lit up when the drive is within 10% (+/- 10 PSI) of
parameter 3-03. When a relay is programmed for “Running on Reference” like you did
earlier, main menu parameter 20-84 sets the bandwidth.
Setup Enhancement
You noticed earlier that the drive would only slow to 20 Hz when running. The only reason it
slows to the programmed minimum speed is because the feedback is above the set-point. An
example of where this might happen is at an apartment building. When nighttime comes
around and all the water faucets are turned off, the pressure would begin to climb and the
drive would speed down in order to stop creating excess pressure. It would not be desirable
for the drive to continue to run at 20 Hz all night long. Enter the parameters below to allow the
drive to “Sleep” when the pressure holds and there is no demand. Use the “Info” key when
you are at these parameters to gain an understanding of what they do.
22-22 - Enabled
22-23 - Sleep Mode
22-24 - 10 Seconds
22-29 - 20 Hz
22-40 - 10 seconds
22-41 - 10 seconds
22-44 - 10%
9
Crank the feedback above the set-point. When the drive reaches 20 Hz, count down
10 seconds and the drive should enter “Sleep Mode”.
9
Wait 10 seconds and then slowly decrease the feedback until it drops 10% (22-44)
below the set-point. The drive should wake up and start modulating again.
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