2.8.7 Reference Handling
Details for Open Loop and Closed Loop operation.
Illustration 2.17 Block Diagram Showing Remote Reference
The Remote Reference is comprised of:
•
Preset references.
•
External references (analog inputs, pulse
frequency inputs, digital potentiometer inputs
and serial communication bus references).
•
The Preset relative reference.
•
Feedback controlled setpoint.
Up to 8 preset references per set-up (4 set-up= 32) 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
). Digipot is a digital
potentiometer. This is also commonly called a Speed Up/
Speed Down Control or a Floating Point Control. To set it
up, one digital input is programmed to increase the
reference while another digital input is programmed to
decrease the reference. A third digital input can be used to
reset the Digipot reference. All reference resources and the
Introduction
VLT
®
Refrigeration Drive Design Guide
MG16G102 - VLT
®
is a registered Danfoss trademark
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