Reference Handling - Danfoss VLT AQUA Drive FC 202 Design Manual

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2.4.4 Reference Handling

Reference handling is applicable in both open and closed
loop operation.
Internal and external references
Up to 8 internal preset references can be programmed into
the frequency converter. The active internal preset
reference can be selected externally through digital control
inputs or the serial communications bus.
External references can also be supplied to the converter,
most commonly through an analog control input. All
reference sources and the bus reference are added to
produce the total external reference. The external
reference, the preset reference, the setpoint, or the sum of
all 3 can be selected as the active reference. This reference
can be scaled.
The scaled reference is calculated as follows:
Y
Reference = X + X ×
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 scaling
does not affect the reference.
Remote reference
A remote reference is comprised of the following (see
Illustration 2.15).
•
Preset references
•
External references (analog inputs, pulse
frequency inputs, digital potentiometer inputs,
and serial communication bus references)
•
A preset relative reference
•
A feedback controlled setpoint
MG20N602
Design Guide
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