Dead Band Around Zero - Danfoss VLT Midi Drive FC 280 Design Manual

Product Overview
The endpoints P1 and P2 are defined in Table 2.4 depending on the choice of input.
2 2
Input
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 2.4 P1 and P2 Endpoints

2.4.4 Dead Band Around Zero

Sometimes, the reference (in rare cases also the feedback) should have a dead band around 0 to ensure that the machine is
stopped when the reference is near 0.
To make the dead band active and to set the amount of dead band, do the following:
•
Set either the minimum reference value (see Table 2.4 for relevant parameter) or maximum reference value at 0. In
other words, either P1 or P2 must be on the X-axis in Illustration 2.18.
•
Ensure that both points defining the scaling graph are in the same quadrant.
P1 or P2 defines the size of the dead band as shown in Illustration 2.18.
Quadrant 2
High reference/feedback
value
Low reference/feedback
value
Quadrant 3
Illustration 2.18 Size of Dead Band
Case 1: Positive reference with dead band, digital input to trigger reverse, part I
Illustration 2.19 shows how reference input with limits inside minimum to maximum limits clamps.
24
VLT
Analog 53
voltage mode
Parameter 6-14 Te
rminal 53 Low
Ref./Feedb. Value
Parameter 6-10 Te
rminal 53 Low
Voltage [V]
Parameter 6-15 Te
rminal 53 High
Ref./Feedb. Value
Parameter 6-11 Te
rminal 53 High
Voltage [V]
Resource output
Quadrant 1
[Hz] or "No unit"
50
P2
forward
P1
0
1 16
Terminal X high
Terminal low
-50
reverse
Quadrant 4
Danfoss A/S © 03/2016 All rights reserved.
®
Midi Drive FC 280
Analog 54 Analog 54
voltage mode current mode
Parameter 6-24 Te Parameter 6-24 Ter
rminal 54 Low minal 54 Low Ref./
Ref./Feedb. Value Feedb. Value
Parameter 6-20 Te Parameter 6-22 Ter
rminal 54 Low minal 54 Low
Voltage [V] Current [mA]
Parameter 6-25 Te Parameter 6-25 Ter
rminal 54 High minal 54 High Ref./
Ref./Feedb. Value Feedb. Value
Parameter 6-21 Te Parameter 6-23 Ter
rminal 54 High minal 54 High
Voltage [V] Current [mA]
Resource input
[mA]
20
Pulse Input 29 Pulse Input 33
Parameter 5-52 Ter Parameter 5-57 Term. 33
m. 29 Low Ref./ Low Ref./Feedb. Value
Feedb. Value
Parameter 5-50 Ter Parameter 5-55 Term. 33
m. 29 Low Low Frequency [Hz]
Frequency [Hz]
Parameter 5-53 Ter Parameter 5-58 Term. 33
m. 29 High Ref./ High Ref./Feedb. Value
Feedb. Value
Parameter 5-51 Ter Parameter 5-56 Term. 33
m. 29 High High Frequency [Hz]
Frequency [Hz]
MG07B102