Reference Limits - Danfoss VLT AutomationDrive FC 300 Design Manual

Introduction
The Remote Reference is calculated once every scan
interval and initially consists of two types of reference
inputs:
1. X (the actual reference): A sum (see
3-04 Reference Function) of up to four externally
selected references, comprising any combination
3 3
(determined by the setting of 3-15 Reference
Resource 1, 3-16 Reference Resource 2 and
3-17 Reference Resource 3) of a fixed preset
reference (3-10 Preset Reference), variable analog
references, variable digital pulse references, and
various serial bus references in whatever unit the
frequency converter is controlled ([Hz], [RPM],
[Nm] etc.).
2. Y- (the relative reference): A sum of one fixed
preset reference (3-14 Preset Relative Reference)
and one variable analog reference (3-18 Relative
Scaling Reference Resource) in [%].
The two types of reference inputs are combined in the
following formula: Remote reference = X + X * Y/100%. If
relative reference is not used 3-18 Relative Scaling Reference
Resource must be set to [0] No function and 3-14 Preset
Relative Reference to 0%. The catch up/slow down function
and the freeze reference function can both be activated by
digital inputs on the frequency converter. The functions
and parameters are described in the Programming Guide.
The scaling of analog references are described in
parameter groups 6-1* Analog Input 1 and 6-2* Analog
Input 2, and the scaling of digital pulse references are
described in parameter group 5-5* Pulse Input.
Reference limits and ranges are set in parameter group

3-0* Reference Limits.

3.3.1 Reference Limits
3-00 Reference Range, 3-02 Minimum Reference and
3-03 Maximum Reference define the allowed range of the
sum of all references. The sum of all references are
clamped when necessary. The relation between the
resulting reference (after clamping) and the sum of all
references is shown in Illustration 3.10.
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VLT AutomationDrive FC 300 Design Guide, 0.25-75 kW
P 3-00 Reference Range= [0] Min-Max
P 3-03
P 3-02
-P 3-02
-P 3-03
Illustration 3.10 Relation between Resulting Reference and the
sum of all References
P 3-03
-P 3-03
Illustration 3.11 Resulting Reference
The value of 3-02 Minimum Reference can not be set to less
than 0, unless 1-00 Configuration Mode is set to [3] Process.
In that case the following relations between the resulting
reference (after clamping) and the sum of all references is
as shown in Illustration 3.12.
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Resulting reference
Forward
Reverse
P 3-00 Reference Range =[1]-Max-Max
Resulting reference
Sum of all
references
Sum of all
references