Parameters 21-** Extended Closed Loop - Danfoss VLT AQUA Drive FC 202 Programming Manual

Parameter Description
3.18 Parameters 21-** Extended Closed
Loop
The FC 202 offers 3 extended closed loop PID controllers
in addition to the PID controller. These can be configured
independently to control either external actuators (valves,
3 3
dampers etc.) or be used together with the internal PID
controller to improve the dynamic responses to setpoint
changes or load disturbances.
The extended closed loop PID controllers may be intercon-
nected or connected to the PID closed loop controller to
form a dual loop configuration.
To control a modulating device (e.g. a valve motor), this
device must be a positioning servo motor with built-in
electronics accepting either a 0-10 V (signal from Analog
I/O card MCB 109) or a 0/4-20 mA (signal from Control
Card and/or General Purpose I/O card MCB 101) control
signal.
The output function can be programmed in the following
parameters:
•
Control Card, terminal 42: Parameter 6-50 Terminal
42 Output (setting [113]...[115] or [149]...[151], Ext.
Closed Loop 1/2/3
•
General Purpose I/O card MCB 101, terminal
X30/8: 6-60 Terminal X30/8 Output, (setting [113]...
[115] or [149]...[151], Ext. Closed Loop 1/2/3
•
Analog I/O card MCB 109, terminal X42/7...11:
Parameter 26-40 Terminal X42/7 Output,
parameter 26-50 Terminal X42/9 Output,
parameter 26-60 Terminal X42/11 Output (setting
[113]...[115], Ext. Closed Loop 1/2/3
General Purpose I/O card and Analog I/O card are optional
cards.
3.18.1 21-0* Extended CL Autotuning
The extended PID closed loop PID controllers can each be
auto-tuned, simplifying and saving time during commis-
sioning, whilst ensuring accurate PID control adjustment.
To use PID autotuning it is necessary for the relevant
extended PID controller to have been configured for the
application.
A graphical LCP must be used to react on messages during
the autotuning sequence.
Enabling autotuning, parameter 21-09 PID Auto Tuning puts
the relevant PID controller into PID autotuning mode. The
LCP then directs the user with on-screen instructions.
142
Programming Guide
PID autotuning functions by introducing step changes and
then monitoring the feedback. From the feedback
response, the required values for PID Proportional Gain,
parameter 21-21 Ext. 1 Proportional Gain for EXT CL 1,
parameter 21-41 Ext. 2 Proportional Gain for EXT CL 2 and
parameter 21-61 Ext. 3 Proportional Gain for EXT CL 3 and
Integral Time, parameter 21-22 Ext. 1 Integral Time for EXT
CL 1, parameter 21-42 Ext. 2 Integral Time for EXT CL 2 and
parameter 21-62 Ext. 3 Integral Time for EXT CL 3 are
calculated. PID Differentiation Time, parameter 21-23 Ext. 1
Differentation Time for EXT CL 1, parameter 21-43 Ext. 2
Differentation Time for EXT CL 2 and parameter 21-63 Ext. 3
Differentation Time for EXT CL 3 are set to value 0 (zero).
Normal/Inverse, parameter 21-20 Ext. 1 Normal/Inverse
Control for EXT CL 1, parameter 21-40 Ext. 2 Normal/Inverse
Control for EXT CL 2 and parameter 21-60 Ext. 3 Normal/
Inverse Control for EXT CL 3 are determined during the
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 PID autotuning mode is disabled in
parameter 21-09 PID Auto Tuning. Depending on the system
being controlled, the time required to carry out PID
autotuning could be several minutes.
Excessive feedback sensor noise should be removed using
the input filter (parameter groups 5-5* Pulse Input, 6-**
Analog In/Out, and 26-** Analog I/O Option MCB 109,
Terminal 53/54 Filter Time Constant/Pulse Filter Time
Constant #29/33) before activating PID autotuning.
[0] Auto
[1] Fast Pressure
[2] Slow Pressure
[3] Fast Temperature
[4] Slow
Danfoss A/S © Rev. 2014-01-21 All rights reserved.
21-00 Closed Loop Type
Option: Function:
This parameter defines the application
response. The default mode should be
sufficient for most applications. If the
relative application speed is known, it can
be selected here. This decreases the time
needed for carrying out PID Autotuning.
The setting has no impact on the value of
the tuned parameters and is used only for
the PID auto-tuning sequence.
Temperature
MG20O702