Operating instructions

3.19 Main Menu - Extended Closed
Loop - Group 21
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 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.
In order 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 0-10V (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: Par. 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:
Par. 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:
Par. 26-40 Terminal X42/7 Output, par. 26-50 Terminal
X42/9 Output, par. 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 PID Closed Loop PID controllers (parameter
group 21-**, Ext. Closed Loop) can each be auto-tuned, simpli-
fying and saving time during commissioning, 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 Local Control Panel (LCP) must be used in order to
react on messages during the autotuning sequence.
Enabling autotuning par. 21-09 PID Autotuning puts the
relevant PID controller into PID autotuning mode. The LCP
then directs the user with on-screen instructions.
PID autotuning functions by introducing step changes and
then monitoring the feedback. From the feedback response,
the required values for PID Proportional Gain, par. 21-21 Ext. 1
Proportional Gain for EXT CL 1, par. 21-41 Ext. 2 Proportional
Gain for EXT CL 2 and par. 21-61 Ext. 3 Proportional Gain for
EXT CL 3 and Integral Time, par. 21-22 Ext. 1 Integral Time for
EXT CL 1, par. 21-42 Ext. 2 Integral Time for EXT CL 2 and
par. 21-62 Ext. 3 Integral Time for EXT CL 3 are calculated. PID
Differentiation Time, par. 21-23 Ext. 1 Differentation Time for
EXT CL 1, par. 21-43 Ext. 2 Differentation Time for EXT CL 2 and
par. 21-63 Ext. 3 Differentation Time for EXT CL 3 are set to
value 0 (zero). Normal / Inverse, par. 21-20 Ext. 1 Normal/
Inverse Control for EXT CL 1, par. 21-40 Ext. 2 Normal/Inverse
Control for EXT CL 2 and par. 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 par. 21-09 PID Autotuning.
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 6-**,5-5* and 26-**, Terminal
53/54 Filter Time Constant/Pulse Filter Time Constant #29/33)
before activating PID autotuning.
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 will decrease 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.
[0]
* Auto
[1] Fast Pressure
[2] Slow Pressure
[3] Fast Tempera-
ture
[4] Slow Temper-
ature
21-01 PID Performance
Option: Function:
[0] * Normal Normal setting of this parameter will be suitable for
pressure control in fan systems.
[1] Fast Fast setting would generally be used in pumping
systems, where a faster control response is desirable.
Parameter Description
VLT
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HVAC Drive Programming Guide
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