2.6.5 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 2.5 Block Diagram Showing Remote Reference
The remote reference consists 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 1 of the 3 reference source parameters
(
parameter 3-15 Reference 1 Source
,
parameter 3-16 Reference 2 Source
, and
parameter 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
parameter 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
parameter 3-14 Preset Relative
Reference
in [%].
If Y,
parameter 3-14 Preset Relative Reference
, is set to 0%,
the reference is not affected by the scaling.
Product Overview
VLT
®
Compressor Drive CDS 803
14
Danfoss A/S © 12/2015 All rights reserved.
MG18N202
2
2
