Danfoss VLT 2800 Design Manual page 107

Programming
After a start command, fill-mode operation begins when
the adjustable frequency drive reaches minimum frequency
- set in parameter 201 Output frequency low limit, f
The filled setpoint is a setpoint limit. When minimum
speed is reached, the pressure feedback is evaluated, and
the adjustable frequency drive begins to ramp to the filled-
pressure setpoint at the rate set in parameter 485 fill rate.
The fill rate is dimensioned in units/S. The units are the
units selected in parameter 416 Process units.
When the pressure feedback equals the filled setpoint, the
control transitions to the operating setpoint (Setpoint 1-4,
parameter 215-218) and continues operation in standard
(normal) closed loop mode.
The value to use for the filled setpoint, can be determined
by:
1. Press DISPLAY MODE on the LCP to display
FEEDBACK 1.
NOTICE
Select the units in parameter 416 Process units before this
step.
2. Operate the frequency converter in HAND mode
and slowly advance the speed to fill the pipe
while being careful not to create a water
hammer.
3. An observer at the end of the pipe must be able
to report when the pipe is filled.
4. At that instant, stop the motor, and observe the
value of pressure feedback (have the LCP display
set to observe the feedback before starting).
5. The value of feedback in step 4 is the value to
use in parameter 486 filled setpoint.
The value to set in parameter 485 fill rate can be supplied
by the system engineer from proper calculation or from
experience, or it can be determined experimentally by
performing numerous fill-mode sequences and either
increasing or decreasing the value of this parameter to
obtain the fastest fill without causing a water hammer.
The fill mode is also beneficial when bringing the motor to
a stop as it prevents sudden changes in pressure and flow
which could also cause a water hammer.
MG27E402
Design Guide
.
MIN
Illustration 4.21 Fill Mode Example
485
Value:
OFF/000000.001 - 999999.999 (units/s) -
Function:
Establishes the rate at which the pipe is filled.
Description of choice:
The dimension of this parameter is units/S. The units is the
value selected in parameter 416 Process units. As an
example, the units could be Bar, or MPa, or PSI, etc. If [4]
Bar is the selected unit in parameter 416 Process units, the
number set in this parameter 485 would be dimensioned
as Bar/S. Changes to this parameter can be made in steps
of .001 units.
486
Value:
Parameter 414 - Parameter 205 -
Function:
The value set in this parameter corresponds to the
pressure that exists at the pressure sensor when the pipe
is filled.
Description of choice:
The units of this parameter correspond to the units
selected in Parameter 416 Process units. The minimum value
of this parameter is Fb
feedback FB
Ref (parameter 205 Maximum reference, Ref
max
setpoint can be changed in .01 steps.
Danfoss A/S © Rev. May/2014 All rights reserved.
Fill Rate
Filled Setpoint
(parameter 414 Minimum
min
). The maximum value for this parameter is
MIN
4 4
OFF
Parameter 414
). The
MAX
105