Rockwell Automation 1756-DMF30 ControlLogix Drive Module User Manual
Page 175
Publication 1756-UM522B-EN-P - February 2003
1756-DMD30 Specific Information B-95
765
Posit Actl Load
Holds the accumulated output of the Load Gear Ratio as a 32
bit integer and forms the primary feedback for the position
regulator integral channel. It is very important that the load
gear ratio be precisely set such that the delta pulse count of
one motor revolution equals the delta pulse count of this
parameter. When the position regulator is not enabled, this
parameter is initialized to parameter 762 [Mtr Posit Fdbk] or to
the selected position reference as determined by parameter
740 [Position Control] bit 6.
Default:
Min:
Max:
Type:
File:
Group:
0
-2147483648
2147483648
Non-Linkable, Read Only, 32-bit Integer
Position Control
Interp/Direct
766
Posit FB EGR Mul
A 32 bit integer in the numerator of the load Electronic Gear
Ratio function. It is multiplied by parameter 764 [Posit Load
Fdbk] and divided by parameter 767 [Posit FB EGR Div] to
reflect the load pulse count to the motor (effectively removing
the gear box ratio). The accumulated position values
parameter 763 [Act Motor Posit] and parameter 764 [Posit Actl
Load] will be equal if the ratio is set properly. There may be
some difference due to lost motion in the gear train, but there
should not be an accumulated difference. It is often
necessary to count gear teeth as gear box manufacturers often
approximate exact ratios with decimal numbers. Enter a
negative value in the numerator to account for reversed motor
rotation.
Default:
Min:
Max:
Type:
File:
Group:
1
-2147483648
2147483648
Linkable, Read-Write, 32-bit Integer
Position Control
Interp/Direct
767
Posit FB EGR Div
This is a 32 bit integer that forms the denominator of the load
Electronic Gear Ratio function.
Default:
Min:
Max:
Type:
File:
Group:
1
1
2147483648
Non-Linkable, Read-Write, 32-bit Integer
Position Control
Interp/Direct
768
PositReg P Gain
Sets position regulator gain as measured from position error to
speed reference. The gain number is identically equal to
position regulator bandwidth in rad/sec. For example: A gain
of 10 means that a per unit position error of 0.1 sec. will effect
a 1.0 pu speed change (1 per unit position error is the distance
traveled in 1 sec. at base motor speed). The maximum value of
this parameter is typically 1/3 of the speed bandwidth
(rad/sec) but may be set considerably higher with careful
tuning of the speed regulator output lead/lag filter.
Units:
Default:
Min:
Max:
Type:
File:
Group:
R/S
4
0
200
Linkable, Read-Write, Floating Point
Position Control, Position Control
Interp/Direct, Point to Point
769
Position Error
Actual position error in motor pulse counts. When the position
regulator is not enabled, this 32 bit integer register is
initialized to zero. When the position regulator is enabled, this
parameter contains the running value of position error, often
referred to as “following error”.
Default:
Min:
Max:
Type:
File:
Group:
0
-2147483648
2147483648
Non-Linkable, Read Only, 32-bit Integer
Position Control, Position Control, Position
Control
Interp/Direct, Point to Point, Posit Detection
No.
Name
Description
Values