VLT
®
6000 HVAC Series
■ Reference type
The example shows how the resulting reference is
calculated when Preset references are used together
with Sum and Relative in parameter 210 Reference
type. See Calculation of resulting reference.See
also the drawing in Reference handling.
The following parameters have been set:
Par. 204 Minimum reference: 10 Hz
Par. 205 Maximum reference: 50 Hz
Par. 211 Preset reference: 15%
Par. 308 Terminal 53, analog input: Reference [1]
Par. 309 Terminal 53, min. scaling: 0V
Par. 310 Terminal 53, max. scaling: 10 V
When parameter 210 Reference type is set to Sum
[0], one of the adjusted Preset references (par. 211-
214) will be added to the external referenc
es as a
percentage of the reference range. If terminal 53
is energized by an analog input voltage of 4 V, the
resulting reference will be as f
ollows:
Par. 210 Reference type =Sum[0]
Par. 204 Minimum reference = 10.0 Hz
Reference contribution at 4 V = 16.0 Hz
P
ar. 211Preset reference = 6.0 Hz
Resulting reference = 32.0 Hz
If parameter 210 Reference type is set to Relative
[1], one of the adjusted Preset references (par.
211-214) will be totaled as a percentage of the sum
of the present external references. If terminal 53
is energized by an analog input voltage of 4 V, the
resulting reference will be as follows:
Par. 210 Reference type = Relative [1]
Par. 204 Minimum reference = 10.0 Hz
Reference contribution at 4 V = 16.0 Hz
P
ar. 211Preset reference = 2.4 Hz
Resulting reference = 28.4 Hz
The graph in the next column shows the
resulting reference in relation to the external
reference varied from 0-10 V.
Parameter 210 Reference type has been programmed
for Sum [0] and Relative [1], respectively. In addition,
a graph is shown in which parameter 211 Preset
reference 1 is programmed for 0%.
210 Reference type
(REF. FUNCTION)
Value:
✭Sum (SUM)
[0]
Relative (RELATIVE)
[1]
External/preset (EXTERNAL/PRESET)
[2]
Function:
It is possible to define how the preset references
are to be added to the other references. For
this purpose, Sum or Relative is used. It is also
possible - by using the External/preset function - to
select whether a shift between external references
and preset references is wanted.
See Reference handling.
Description of choice:
If Sum [0] is selected, one of the adjusted preset
references (parameters 211-214 Preset reference)is
added to the other external references as a percentage
of the reference range (Ref
MIN
-Ref
MAX
).
If Relative [1] is selected, one of the adjusted
preset references (parameters 211-214 Preset
reference ) is totaled as a percentage of the sum
of the present external references.
If External/preset [2] is selected, it is possible to shift
between external references and preset references via
terminal 16, 17, 29, 32 or 33 (parameter 300, 301,
305, 306 or 307 Digital inputs). Preset references will
beapercentagevalueofthereferencerange.
External reference is the sum of the analog
references, pulse references and any references
from serial communication.
✭
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.61.A5.02 - VLT is a registered Danfoss trademark
96
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