3.18.4 20-6* Sensorless
Parameters for Sensorless. See also
18-50 Sensorless Readout [unit]
and
NOTE
Sensorless unit and Sensorless Information requires set up by
MCT10 with sensorless specific plug in.
20-60 Sensorless Unit
Option:
Function:
Select the unit to be used with
.
[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
20-69 Sensorless Information
Range:
Function:
0
*
[0 - 0 ]
3.18.5 20-7* PID autotuning
The frequency converter PID Closed Loop controller
(parameters 20-**, FCDrive Closed Loop) can be auto-tuned,
simplifying and saving time during commissioning, whilst
ensuring accurate PID control adjustment. To use auto-
tuning it is necessary for the frequency converter to be
configured for closed loop in
A Graphical Local Control Panel (LCP) must be used in order
to react on messages during the auto-tuning sequence.
Enabling
, puts the frequency converter
into auto-tuning mode. The LCP then directs the user with
on-screen instructions.
The fan/pump is started by pressing [Auto On] button on the
LCP and applying a start signal. The speed is adjusted
manually by pressing the [
▲
] or [
▼
] navigation keys on the
LCP to a level where the feedback is around the system set-
point.
NOTE
It is not possible to run the motor at maximum or minimum
speed, when manually adjusting the motor speed due to the
need of giving the motor a step in the speed during auto-
tuning.
PID auto-tuning functions by introducing step changes
whilst operating at a steady state and then monitoring the
feedback. From the feedback response, the required values
for
and
are calculated.
20-95 PID Differentiation Time
is set to value 0
(zero).
20-81 PID Normal/ Inverse Control
is determined during
tuning process.
These calculated values are presented on the LCP and the
user can decide whether to accept or reject them. Once
accepted, the values are written to the relevant parameters
and auto-tuning mode is disabled in
.
Depending on the system being controlled the time required
to carry out auto-tuning could be several minutes.
It is advised to set the ramp times in
or
and
according to the
load inertia before carrying out PID autotuning. If PID
autotuning is carried out with slow ramp times, the auto-
tuned parameters will typically result in very slow control.
Excessive feedback sensor noise should be removed using
the input filter (parameter groups 6-**, 5-5* and 26-**,
Terminal 53/54 Filter Time Constant/Pulse Filter Time
Constant #29/33) before activating PID autotuning. In order
to obtain the most accurate controller parameters, it is
advised to carry out PID autotuning, when the application is
running in typical operation, i.e. with a typical load.
Parameter Description
VLT
®
HVAC Drive Programming Guide
MG.11.CB.02 - VLT
®
is a registered Danfoss trademark
129
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