3.1.4 Reference Handling
Details for Open Loop and Closed Loop operation.
Speed open
loop
Configuration
mode
Input command:
freeze reference
Process
control
Scale to
Hz
Scale to
process
unit
Remote
reference/
setpoint
±200%
Feedback
handling
Remote
reference in %
maxRefPCT
minRefPct
min-max ref
Freeze
reference &
increase/
decrease
reference
±100%
Input commands:
Speed up/speed down
±200%
Relative
reference
=
X+X*Y/100
±200%
External reference in %
±200%
Parameter choise:
Reference resource 1,2,3
±100%
Preset reference
Input command:
preset ref bit0, bit1, bit2
+
+
Relative scalling reference
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 %
Y
X
130BB900.13
Illustration 3.2 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 two can be selected to be the
active reference. Finally, this reference can by be scaled using
3-14 Preset Relative Reference
.
The scaled reference is calculated as follows:
Reference = X + X ×
(
Y
100
)
Where X is the external reference, the preset reference or the sum of these and Y is
3-14 Preset Relative Reference
in [%].
If Y,
3-14 Preset Relative Reference
is set to 0%, the reference will not be affected by the scaling.
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VLT Micro Drive Design Guide
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