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

Introduction to FC 300
3.2.7 Internal Current Control in VVC
Mode
The frequency converter features an integral current limit
control which is activated when the motor current, and
3 3
thus the torque, is higher than the torque limits set in
4-16 Torque Limit Motor Mode, 4-17 Torque Limit Generator
Mode and 4-18 Current Limit.
When the frequency converter is at the current limit during
motor operation or regenerative operation, the frequency
converter will try to get below the preset torque limits as
quickly as possible without losing control of the motor.
3.2.8 Local (Hand On) and Remote (Auto
On) Control
The frequency converter 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
frequency converter via the LCP using the [Hand ON] and
[Off] keys. Alarms can be reset via the [RESET] key. After
pressing the [Hand ON] key, the frequency converter goes
into Hand mode and follows (as default) the Local
reference that can be set using arrow key on the LCP.
After pressing the [Auto On] key, the frequency converter
goes into Auto mode and follows (as default) the Remote
reference. In this mode, it is possible to control the
frequency converter via the digital inputs and various serial
interfaces (RS-485, USB, or an optional fieldbus). 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
on
Active Reference and Configuration Mode
The active reference can be either the local reference or
the remote reference.
In 3-13 Reference Site the local reference can be
permanently selected by selecting Local [2].
To permanently select the remote reference select Remote
[1]. By selecting Linked to Hand/Auto [0] (default) the
reference site will depend on which mode is active. (Hand
Mode or Auto Mode).
22
FC 300 Design Guide
Auto
O Reset
on
MG.33.BD.02 - VLT
plus
Remote
reference
Auto mode
Hand mode
Local
reference
P 1-05
Local
con guration
mode
Local
reference
Hand OnAutoLCP Keys
Hand
Hand -> Off
Auto
Auto -> Off
All keys
All keys
Table 3.1 Conditions for Local/Remote Reference Activation.
1-00 Configuration Mode determines what kind of
application control principle (i.e. Speed, Torque or Process
Control) is used when the remote reference is active.
1-05 Local Mode Configuration determines the kind of
application control principle that is used when the local
reference is active. One of them is always active, but both
can not be active at the same time.
®
is a registered Danfoss trademark
Remote
Linked to hand/auto
Local
P 3-13
LCP Hand on,
Reference site
o and auto
on keys
P 1-00
Con guration
mode
Speed open/
closed loop
Scale to
RPM or
Hz
Torque
Scale to
Nm
Scale to
process
unit
Process
closed loop
3-13 Reference Site Active Reference
Linked to Hand / Local
Auto
Linked to Hand / Local
Auto
Linked to Hand / Remote
Auto
Linked to Hand / Remote
Auto
Local Local
Remote Remote
Reference
Local
ref.