Main Menu - Extended Closed Loop - Group - Danfoss VLT AQUA FC 200 Series Programming Manual

2 Parameter Description

2.18 Main Menu - Extended Closed Loop - Group 21

2.18.1 21-** Ext. Closed Loop
2
The 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 interconnected 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
• General Purpose I/O card MCB 101, terminal X30/8: par.6-60
1/2/3
• Analog I/O card MCB 109, terminal X42/7...11: par.26-40
Output
(setting [113]...[115], Ext. Closed Loop 1/2/3
General Purpose I/O card and Analog I/O card are optional cards.
2.18.2 21-0* Extended CL autotuning
The extended PID Closed Loop PID controllers (
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
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
Gain for EXT CL 3 and Integral Time, par.21-22
Integral Time for EXT CL 3 are calculated. PID Differentiation Time, par.21-23
Time for EXT CL 2 and par.21-63
Control
for EXT CL 1, par.21-40
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
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.
170
Terminal 42 Output (setting [113]...[115] or [149]...[151], Ext. Closed Loop 1/2/3
par. 21-**, Ext. Closed Loop
PID Autotuning
puts the relevant PID controller into PID autotuning mode. The LCP then directs the user with on-screen
Ext. 1 Proportional Gain
for EXT CL 1, par.21-41
Ext. 1 Integral Time
Ext. 3 Differentation Time for EXT CL 3 are set to value 0 (zero). Normal / Inverse, par.21-20
Ext. 2 Normal/Inverse Control
for EXT CL 2 and par.21-60
MG.20.O4.02 - VLT
Terminal X30/8 Output
, (setting [113]...[115] or [149]...[151], Ext. Closed Loop
Terminal X42/7 Output Terminal X42/9 Output
, par.26-50
) can each be auto-tuned, simplifying and saving time during commissioning,
Ext. 2 Proportional Gain
for EXT CL 1, par.21-42 Ext. 2 Integral Time
Ext. 1 Differentation Time
Ext. 3 Normal/Inverse Control
PID Autotuning
. Depending on the system being controlled the time required
®
is a registered Danfoss trademark
®
VLT AQUA Drive Programming Guide
Terminal X42/11
, par.26-60
Ext. 3 Proportional
for EXT CL 2 and par.21-61
for EXT CL 2 and par.21-62
for EXT CL 1, par.21-43 Ext. 2 Differentation
Ext. 1 Normal/Inverse
for EXT CL 3 are determined
Ext. 3