3.19 Parameters: 21-** Main Menu -
Extended Closed Loop
The FC 102 offers 3 extended closed-loop PID controllers in
addition to the PID controller. These can be configured
independently to control either external actuators (valves,
dampers and so on.) or be used 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 (for example 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:
(setting [113]...[115] or [149]...[151], Ext.
Closed Loop 1/2/3
•
General purpose I/O card MCB 101, terminal
X30/8:
Parameter 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.
3.19.1 21-0* Extended CL Autotuning
The extended closed-loop PID controllers can each be
autotuned, simplifying and saving time during commis-
sioning, while ensuring accurate PID control adjustment.
To use PID auto tuning, configure for the relevant
extended PID controller for the application.
Use a graphical LCP to react on messages during the auto-
tuning sequence.
Enabling auto tuning,
parameter 21-09 PID Autotuning
puts
the relevant PID controller into PID autotuning mode. The
LCP then provides on-screen instructions.
PID auto tuning functions by introducing step changes and
then monitoring the feedback. Based on the feedback
response, the following required values are calculated:
•
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.
-
Parameter 21-61 Ext. 3 Proportional Gain
for EXT CL 3.
•
Integral time.
-
Parameter 21-22 Ext. 1 Integral Time
for
EXT CL 1.
-
Parameter 21-42 Ext. 2 Integral Time
for
EXT CL 2.
-
Parameter 21-62 Ext. 3 Integral Time
for
EXT CL 3 are calculated.
The PID differentiation time is set to 0 in the following
parameters:
•
Parameter 21-23 Ext. 1 Differentation Time
for EXT
CL 1.
•
Parameter 21-43 Ext. 2 Differentation Time
for EXT
CL 2 .
•
Parameter 21-63 Ext. 3 Differentation Time
for EXT
CL 3 are set to value 0 (zero).
•
Parameter 21-20 Ext. 1 Normal/Inverse Control
for
EXT CL 1.
•
Parameter 21-40 Ext. 2 Normal/Inverse Control
for
EXT CL 2.
•
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 can
either be accepted or rejected. Once accepted, the values
are written to the relevant parameters and PID autotuning
mode is disabled in
parameter 21-09 PID Autotuning
.
Depending on the system being controlled, the time
required to carry out PID auto tuning could be several
minutes.
Before activating the PID auto tuning, remove excessive
feedback sensor noise 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.
Parameter Descriptions
Programming Guide
MG11CE02
Danfoss A/S © 03/2015 All rights reserved.
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