Case 2: Positive reference with dead band, digital input to trigger reverse. Clamping rules.
Illustration 2.11 shows how reference input with limits outside -Max to +Max limits clamps to the inputs low and high limits
before addition to external reference. And how the external reference is clamped to -Max to +Max by the Reference
algorithm.
+
30 Hz
1
10
20 Hz
1
10
130BD433.10
-20 Hz
V
V
Analog input 53
Low reference 0 Hz
High reference 20 Hz
Low voltage 1 V
High voltage 10 V
Ext. source 1
Range:
0.0% (0 Hz)
150.0% (30 Hz)
150.0% (30 Hz)
Ext. reference
Range:
0.0% (0 Hz)
30 Hz 10 V
Ext. Reference
Absolute
0 Hz 1 V
Reference
algorithm
Reference
100.0% (20 Hz)
0.0% (0 Hz)
Range:
Limited to:
-100%- +100%
(-20 Hz- +20 Hz)
Limited to: -200%- +200%
(-40 Hz- +40 Hz)
Reference is scaled
according to
max reference giving a
speed.!!!
Scale to
speed
+20 Hz
-20 Hz
Range:
Speed
setpoint
Motor
control
Range:
-8 Hz
+8 Hz
Motor
Digital input 19
Low No reversing
High Reversing
Limits Speed Setpoint
according to min max speed.!!!
Motor PID
Dead band
Digital input
General Reference
parameters:
Reference Range: -Max - Max
Minimum Reference: Don't care
Maximum Reference: 20 Hz (100.0%)
General Motor
parameters:
Motor speed direction: Both directions
Motor speed Low limit: 0 Hz
Motor speed high limit: 10 Hz
Illustration 2.11 Clamping of Reference Input with Limits outside -Min to +Max
Product Overview
VLT
®
AutomationDrive FC 360 Design Guide
MG06B202 - VLT
®
is a registered Danfoss trademark 23
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