Dead Band Around Zero - Danfoss VLT AutomationDrive FC 300 Design Manual

Product Introduction
The endpoints P1 and P2 are defined by the following parameters, depending on which analog or pulse input is used
Analog 53
S201=OFF
P1=(Minimum input value, Minimum reference value)
Minimum reference value 6-14 Terminal
53 Low Ref./
Feedb. Value
Minimum input value 6-10 Terminal
53 Low
Voltage [V]
P2 =(Maximum input value, Maximum reference value)
Maximum reference value 6-15 Terminal
53 High Ref./
Feedb. Value
Maximum input value 6-11 Terminal
53 High
Voltage [V]
Table 3.5 P1 and P2 Parameters

3.3.4 Dead Band around Zero

In some cases, the reference and, in rare instances, the feedback needs a dead band around zero. This is used to ensure the
machine is stopped when the reference is "near zero".
To make the dead band active and to set the amount of dead band, apply the following settings:
•
Minimum reference value (see Table 3.5 for relevant parameter) or maximum reference value must be zero. In
other words, Either P1 or P2 must be on the X-axis in Figure 3.16.
•
Both points defining the scaling graph must be in the same quadrant.
The size of the dead band is defined by either P1 or P2 as shown in Figure 3.16.
Quadrant 2 Resource output
(RPM)
High reference/feedback
1500
value
Low reference/feedback
0 P1
value
-10 -6 -1 1
Terminal X
low
-1500
Quadrant 3
Figure 3.16 Dead Band
Thus a reference endpoint of P1=(0 V,
0 RPM) does not result in any dead band, but a reference endpoint of P1=(1 V, 0 RPM), results in a -1 V to +1 V dead band
provided that the end point P2 is placed in either Quadrant 1 or Quadrant 4.
MG34S222
Design Guide
Analog 53 Analog 54
S201=ON S202=OFF
6-14 Terminal 53 6-24 Terminal
Low Ref./Feedb. 54 Low Ref./
Value Feedb. Value
6-12 Terminal 53 6-20 Terminal
Low Current 54 Low
[mA] Voltage [V]
6-15 Terminal 53 6-25 Terminal
High Ref./Feedb. 54 High Ref./
Value Feedb. Value
6-13 Terminal 53 6-21 Terminal
High Current 54 High
[mA] Voltage [V]
Quadrant 1
P2
Resource
input
(V)
6 10
Terminal X
high
Quadrant 4
Danfoss A/S © Rev. 2014-02-10 All rights reserved.
Analog 54 Pulse input 29
S202=ON
6-24 Terminal 54 5-52 Term. 29
Low Ref./Feedb. Low Ref./Feedb.
Value Value
6-22 Terminal 54 5-50 Term. 29
Low Current Low Frequency
[mA] [Hz]
6-25 Terminal 54 5-53 Term. 29
High Ref./Feedb. High Ref./
Value Feedb. Value
6-23 Terminal 54 5-51 Term. 29
High Current High Frequency
[mA] [Hz]
Quadrant 2 Resource output
(RPM)
1500
Low reference/feedback
P1
value
High reference/feedback
P2 0
value
-10 -6 -1 1
Terminal X Terminal X
low high
-1500
Quadrant 3
Figure 3.17 Reverse Dead Band
Pulse input 33
3
5-57 Term. 33 Low
Ref./Feedb. Value
5-55 Term. 33 Low
Frequency [Hz]
5-58 Term. 33 High
Ref./Feedb. Value
5-56 Term. 33 High
Frequency [Hz]
Quadrant 1
Resource
input
(V)
6 10
Quadrant 4
33
3