Dead Band Around Zero - Danfoss VLT Decentral Drive FCD 302 Design Manual

Product Overview
2 2 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
Table 2.6 Input and Reference Endpoint Values

2.3.4 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 2.6 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 Illustration 2.15.
Quadrant 2
High reference/feedback
value
Low reference/feedback
value
-10 -6
Quadrant 3
Illustration 2.15 Dead Band
20
®
VLT
Analog 53 Analog 53
S201=OFF S201=ON
6-14 Terminal 6-14 Terminal 53
53 Low Ref./ Low Ref./Feedb.
Feedb. Value Value
6-10 Terminal 6-12 Terminal 53
53 Low Voltage Low Current
[V] [mA]
6-15 Terminal 6-15 Terminal 53
53 High Ref./ High Ref./Feedb.
Feedb. Value Value
6-11 Terminal 6-13 Terminal 53
53 High High Current
Voltage [V] [mA]
Resource output Quadrant 1
(RPM)
P2
1500
Resource
input
0 P1
(V)
-1 1 6 10
Terminal X Terminal X
low high
-1500
Quadrant 4
MG04H102 - VLT
Decentral Drive FCD 302
Analog 54 Analog 54
S202=OFF S202=ON
6-24 Terminal 6-24 Terminal 54
54 Low Ref./ Low Ref./Feedb.
Feedb. Value Value
6-20 Terminal 6-22 Terminal 54
54 Low Voltage Low Current
[V] [mA]
6-25 Terminal 6-25 Terminal 54
54 High Ref./ High Ref./Feedb.
Feedb. Value Value
6-21 Terminal 6-23 Terminal 54
54 High High Current[mA]
Voltage[V]
Quadrant 2
High reference/feedback
value
-10 -6
Terminal X
low
Quadrant 3
Illustration 2.16 Reverse Dead Band
Thus a reference endpoint of P1=(0 V, 0 RPM) will not
result in any dead band, but a reference endpoint of e.g.
P1=(1 V, 0 RPM) will result in a -1V to +1V dead band in
this case provided that the end point P2 is placed in either
Quadrant 1 or Quadrant 4.
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is a registered Danfoss trademark
Pulse Input 29 Pulse Input 33
5-52 Term. 29 5-57 Term. 33 Low
Low Ref./Feedb. Ref./Feedb. Value
Value
5-50 Term. 29 5-55 Term. 33 Low
Low Frequency Frequency [Hz]
[Hz]
5-53 Term. 29 5-58 Term. 33 High
High Ref./Feedb. Ref./Feedb. Value
Value
5-51 Term. 29 5-56 Term. 33 High
High Frequency Frequency [Hz]
[Hz]
Resource output Quadrant 1
(RPM)
1500
Low reference/feedback
P1
value
Resource
P2 0
input
-1 1 6 10
Terminal X
high
-1500
Quadrant 4
(V)