Reference Handling - Danfoss VLT FC51 Design Manual

Product Overview

3.1.4 Reference Handling

Details for open loop and closed loop operation.
3 3
Intern resource
Preset relative reference
±100%
Preset reference 0 ±100%
Preset reference 1 ±100%
Preset reference 2 ±100%
Preset reference 3 ±100%
Preset reference 4 ±100%
Preset reference 5 ±100%
Preset reference 6 ±100%
Preset reference 7 ±100%
Extern resource 1
No function
Analog reference
±200 %
Local bus reference
±200 %
LCP potmeter 0~100 %
Extern resource 2
No function
Analog reference
±200 %
Local bus reference
±200 %
LCP potmeter 0~100 %
Extern resource 3
No function
Analog reference
±200 %
Local bus reference
±200 %
LCP potmeter 0~100 %
Illustration 3.4 Block Diagram Showing Remote Reference
The remote reference is comprised of:
•
Preset references
•
External references (analog inputs and serial communication bus references)
•
The preset relative reference
•
Feedback controlled setpoint
Up to 8 preset references can be programmed in the frequency converter. The active preset reference can be selected using
digital inputs or the serial communications bus. The reference can also be supplied externally, most commonly from an
analog input. This external source is selected by one of the 3 Reference Source parameters (3-15 Reference 1 Source,
3-16 Reference 2 Source and 3-17 Reference 3 Source). All reference resources and the bus reference are added to produce the
total external reference. The external reference, the preset reference or the sum of the 2 can be selected to be the active
reference. Finally, this reference can by be scaled using 3-14 Preset Relative Reference.
20
VLT
Relative scalling reference
Input command:
preset ref bit0, bit1, bit2
Preset reference
±100%
Y
X
+
Parameter choise:
Reference resource 1,2,3
±200%
+
±200%
External reference in %
®
Micro Drive FC 51 Design Guide
Input command:
freeze reference
maxRefPCT
Relative
reference
=
±200%
X+X*Y/100
minRefPct
min-max ref
±100%
Freeze
reference &
increase/
decrease
reference
Input commands:
Speed up/speed down
MG02K302 - Rev. 2013-12-03
Speed open
loop
Configuration
Scale to
mode
Hz
Remote
reference/
setpoint
Process
control
Scale to
process
unit
±200%
Feedback
handling
Remote
reference in %