Advanced Pid Control; Internal Current Control In Vvc Plus Mode; Local (Hand On) And Remote (Auto On) Control - Danfoss VLT AutomationDrive FC 301 Series Design Manual

Basic Operating Principles
Parameter
5-54 Pulse Filter Time Constant #29 (Pulse
term. 29),
5-59 Pulse Filter Time Constant #33 (Pulse
term. 33),
6-16 Terminal 53 Filter Time Constant (Analog
term 53),
6-26 Terminal 54 Filter Time Constant (Analog
term. 54)
6-36 Term. X30/11 Filter Time Constant
6-46 Term. X30/12 Filter Time Constant
35-46 Term. X48/2 Filter Time Constant
Table 3.5 Relevant Parameters for Process Control

3.6.6.4 Advanced PID Control

®
Consult the VLT AutomationDrive FC 301/FC 302 Programming Guide for advanced PID control parameters
3.6.7 Internal Current Control in VVC
When the motor current/torque exceed the torque limits set in 4-16 Torque Limit Motor Mode, 4-17 Torque Limit Generator
Mode and 4-18 Current Limit, the integral current limit control is activated.
When the adjustable frequency drive is at the current limit during motor operation or regenerative operation, it tries to get
below the preset torque limits as quickly as possible without losing control of the motor.

3.6.8 Local (Hand On) and Remote (Auto On) Control

The adjustable frequency drive can be operated manually via the local control panel (LCP), or remotely via analog and
digital inputs and serial bus. If allowed in 0-40 [Hand on] Key on LCP, 0-41 [Off] Key on LCP, 0-42 [Auto on] Key on LCP, and
0-43 [Reset] Key on LCP, it is possible to start and stop the adjustable frequency drive via the LCP pressing [Hand On] and
[Off]. Alarms can be reset via [Reset]. After pressing [Hand On], the adjustable frequency drive goes into Hand mode and
follows (as default) the local reference that can be set using the navigation keys on the LCP.
After pressing [Auto On], the adjustable frequency drive enters Auto mode and follows (as default) the remote reference. In
this mode, it is possible to control the adjustable frequency drive via the digital inputs and various serial interfaces (RS-485,
USB, or an optional serial communication bus). See more about starting, stopping, changing ramps and parameter set-ups,
etc. in parameter group 5-1* Digital Inputs or parameter group 8-5* Serial communication.
Hand
O
on
Figure 3.10 Operation Keys
MG33BF22
Design Guide
Description of function
If there are oscillations of the current/voltage feedback signal, these can be dampened by
means of a low-pass filter. This time constant represents the speed limit of the ripples
occurring on the feedback signal.
Example: If the low-pass filter has been set to 0.1s, the limit speed is 10 RAD/s (the
reciprocal of 0.1 s), corresponding to (10/(2 x π)) = 1.6 Hz. This means that all currents/
voltages that vary by more than 1.6 oscillations per second are damped by the filter. The
control is only carried out on a feedback signal that varies by a frequency (speed) of less
than 1.6 Hz.
The low-pass filter improves steady state performance, but selecting a filter time that is
too long causes the dynamic performance of the Process PID Control to deteriorate.
plus
Mode
Auto
Reset
on
Rev. 2014-04-04 All rights reserved.
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