Reference Limits - Danfoss VLT AutomationDrive FC 300 Design Manual

Product Introduction
The remote reference is calculated once every scan
interval and initially consists of the following reference
inputs:
•
X (External): A sum (see 3-04 Reference Function)
of up to four externally selected references,
comprising any combination 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
adjustable frequency drive is controlled ([Hz],
[RPM], [Nm], etc). The combination is determined
by the setting of 3-15 Reference Resource 1,
3-16 Reference Resource 2 and 3-17 Reference
Resource 3.
•
Y (Relative): 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 the
relative reference is not used, 3-18 Relative Scaling
Reference Resource must be set to 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 adjustable frequency
drive. The functions and parameters are described in the
Programming Guide.
The scaling of analog references is described in parameter
groups 6-1* Analog Input 1 and 6-2* Analog Input 2, and
the scaling of digital pulse references is described in
parameter group 5-5* Pulse Input 2.
Reference limits and ranges are set in parameter group

3-0* Reference Limits.

MG34S222
Design Guide
3.3.1 Reference Limits
3-00 Reference Range, 3-02 Minimum Reference, and
3-03 Maximum Reference together define the range of the
sum of all references. The sum of all references is clamped
when necessary. The relation between the resulting
reference (after clamping) and the sum of all references is
shown in Figure 3.11 and Figure 3.12.
Figure 3.11 Relation between Resulting Reference and the
Sum of All References
Figure 3.12 Resulting Reference
Danfoss A/S © Rev. 2014-02-10 All rights reserved.
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