PowerFlex Digital DC Drive User Manual -
Publication 20P-UM001C-EN-P - July 2008
Application Notes
C-23
Speed Draw Function
The Speed Draw function can be used to apply a configurable speed ratio
(set in Par 1017 [Speed Ratio]) to the main speed reference of the drive.
This function is useful in a multi-drive system where a proportional speed
increase between the motors is required. The range of parameter 1017
[Speed Ratio] can be set between 0 and 32767 if written in digital form, or
can be set from 0 to 20000 (0 to +10V) if assigned via an analog input. The
resulting speed value can be viewed in Par 1018 [Speed Draw Out] via an
analog output.
Figure C.4 Speed Draw Example
Speed Draw Example Configuration
Drive A:
•
Set parameter 70 [Anlg In1 Sel] to 4 “Trim Speed”
Drive B:
•
Set parameter 70 [Anlg In1 Sel] to 4 “Trim Speed”
•
Set parameter 75 [Anlg In2 Sel] to 22 “Speed Ratio”
•
Set parameter 1017 [Speed Ratio] to 10500
Drive C:
•
Set parameter 70 [Anlg In1 Sel] to 4 “Trim Speed”
•
Set parameter 75 [Anlg In2 Sel] to 22 “Speed Ratio”
•
Set parameter 1017 [Speed Ratio] to 11000
M
Drive A
Master = 1000 RPM
1050 RPM
1100 RPM
+
Line Speed
M
Drive B
M
Drive C
+
+
Line Speed
ratio 1 = +5%
Anlg Input
1
Anlg Input
1 2
Anlg Input
1 2
Speed Ratio = 5.25V
(10500 count)
Line Speed
ratio 2 = +10%
Speed Ratio = 5.5V
(11000 count)
