Scaling Of References And Feedback; Dead Band Around Zero - Danfoss FC 300 Design Manual

FC 300 Design Guide

Scaling of References and Feedback

References and feedback are scaled from analog and pulse inputs in the same way. The only difference
is that a reference above or below the specified minimum and maximum "endpoints" (P1 and P2 in the
graph below) are clamped whereas a feedback above or below is not.
The endpoints P1 and P2 are defined by the following parameters depending on which analog or pulse
input is used
P1 = (Minimum input value, Minimum reference value)
Minimum reference value
Minimum input value
P2 = (Maximum input value, Maximum reference value)
Maximum reference value
Maximum input value

Dead Band Around Zero

In some cases the reference (in rare cases also the feedback) should have a Dead Band around zero
(i.e. to make sure the machine is stopped when the reference is "near zero"). To make the dead band
active and to set the amount of dead band, the following settings must be done:
• Either Minimum Reference Value (see table above for relevant parameter) or Maximum Reference
Value must be zero. In other words; Either P1 or P2 must be on the X-axis in the graph below.
• And both points defining the scaling graph are in the same quadrant.
The size of the Dead Band is defined by either P1 or P2 as shown in the graph below.
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Introduction to FC 300
Analog 53 Analog 53
S201=OFF S201=ON
Par. 6-14 Par. 6-14
Par. 6-10 [V] Par. 6-12 [mA]
Par. 6-15 Par. 6-15
Par. 6-11 [V] Par. 6-13 [mA]
MG.33.B7.02 - VLT is a registered Danfoss trademark
Analog 54 Analog 54
S202=OFF S202=ON
Par. 6-24 Par. 6-24
Par. 6-20 [V] Par. 6-22 [mA]
Par. 6-25 Par. 6-25
Par. 6-21 [V] Par. 6-23 [mA]
Pulse Input 29 Pulse Input 33
Par. 5-52 Par. 5-57
Par. 5-50 [Hz] Par. 5-55 [Hz]
Par. 5-53 Par. 5-58
Par. 5-51 [Hz] Par. 5-56 [Hz]