Danfoss VLT FC 102 Programming Manual page 186

Parameter Descriptions
20-38 Air Density Factor [%]
Range:
100 %
*
3 3
3.18.4 20-6* Sensorless
Parameters for sensorless. See also:
•
Parameter 20-00 Feedback 1 Source
•
Parameter 18-50 Sensorless Readout [unit]
•
Parameter 16-26 Power Filtered [kW]
•
Parameter 16-27 Power Filtered [hp]
NOTICE
Sensorless unit and sensorless information require set-up
by MCT 10 Set-up Software with sensorless specific plug
in.
20-60 Sensorless Unit
Option:
[20] l/s
[21] l/min
[22] l/h
[23] m³/s
[24] m³/min
[25] m³/h
[70] mbar
[71] bar
[72] Pa
[73] kPa
[74] m WG
[75] mm Hg
[120] GPM
[121] gal/s
[122] gal/min
[123] gal/h
[124] CFM
[125] ft³/s
[126] ft³/min
[127] ft³/h
[170] psi
[171] lb/in²
[172] in WG
[173] ft WG
[174] in Hg
184
Function:
[50 - 150 %] Set the air density factor for
conversion from pressure to flow in
% relative to the air density at sea
level at 20 °C (100% ~ 1,2 kg/m
Function:
Select the unit to be used with
parameter 18-50 Sensorless Readout
[unit].
Danfoss A/S © 10/2019 All rights reserved.
®
VLT HVAC Drive FC 102
20-69 Sensorless Information
Range:
0
*
3
).
3.18.5 20-7* Auto-tuning
PID auto-tuning
The frequency converter closed-loop controller (parameter
group 20-** FC Closed Loop) can be auto-tuned, simplifying
and saving time during commissioning, while ensuring
accurate control adjustment. To use auto-tuning, configure
the frequency converter for closed loop in
parameter 1-00 Configuration Mode.
Use a graphical local control panel (GLCP) to react to
messages during the auto-tuning sequence.
Selecting either PID or SPC in parameter 20-79 PID
Autotuning puts the frequency converter into auto-tuning
mode. The LCP then shows on-screen instructions.
To start the fan/pump, press [Auto On] and apply a start
signal. The default control settings ensure that the setpoint
it eventually reached. For PID auto-tuning, it is possible to
adjust the speed manually by pressing [
where the feedback is around the system setpoint.
CAUTION
If the feedback goes outside the specified limits (2073
and 2074) defined during auto-tune set-up, the auto-
tuning is discarded. The limits also serve as application
protection during auto-tuning execution.
NOTICE
It is not possible to run the motor at maximum or
minimum speed when manually adjusting the motor
speed due to the need of increasing or decreasing the
motor speed during auto-tuning.
Auto-tuning introduces step changes while operating at a
steady state and then monitors the feedback. For PID
control, the auto-tuning feedback response defines the
required values for parameter 20-93 PID Proportional Gain
and parameter 20-94 PID Integral Time are calculated.
Parameter 20-95 PID Differentiation Time is set to value 0
(zero). Parameter 20-81 PID Normal/ Inverse Control is
determined during the tuning process.
These calculated values are presented in the LCP and can
be either accepted or rejected. Once accepted, the values
are written to the relevant parameters and auto-tuning
mode is disabled in parameter 20-79 PID Autotuning.
Depending on the system, the time required to carry out
auto-tuning could be several minutes.
Function:
[0 - 25 ] View information about the
sensorless data.
▲
] or [
▼
] to a level
M0010001