Rockwell Automation 8720MC Drives Integration Manual - Manual (Page 131)

Publication 8720MC-IN002A-EN-P — December 2002
Programming Parameters C-19
Name: Motor_Posn_Fback Data Display: Resolution Units R
Parameter No.
51
File:
Control
Group:
Position Description: Position feedback value 1 (motor feedback). In the analog spindle and power servo configurations
the feedback is always scaled for rotary feedback with modulo format using parameter scaling. This means that
the resolution of the feedback as displayed in parameter 51 is defined by parameter 79 and the feedback is
modulo in that it ranges from 0 to parameter 103 counts absolute and rolls over to zero. In the analog spindle and
power servo configurations the absolute zero of the rotary axis feedback can be shifted clockwise or
counter-clockwise via parameter 150, “Motor Marker Offset”. The HIM display of parameter 51 in the analog
configurations will be the absolute accumulation of the modulo axis feedback after it is modified by parameter
150. This is true after the first orient regardless of whether the feedback type is incremental or single turn
absolute. In the analog version the display is in rotary resolution units as defined in parameter 79. It’s range will
be 0 to parameter 103, the modulo rotary axis value.
Default:
N/A Length
2 bytes SCANport Min/Max
Min.
≥ -32768
Max.
≤ +32767
SCANport Scaling Resolution
360/parameter 79 = rotary position increment in
deg. Units
parameter
79
Default:
N/A Length
4 bytes SERCOS/DPI Min/Max
Min.
≥ -2 31
Max.
≤ +2 31
- 1
SERCOS/DPI Scaling Resolution
Scaling type: parameter 76
Scaling factor: parameter 77
Scaling exponent: parameter 78
Rotational position resolution: parameter 79 Units
parameter
76
Name: Aux_Posn_Fback Data Display: Decimal R
Parameter No.
53
File:
Control
Group:
Position Description: Position feedback value 2 (auxiliary feedback). It is used for slide or spindle mounted feedback
devices such as linear scales or toothed wheel spindle encoders. This parameter is not available for analog
configurations.
Default:
N/A Length
4 bytes SERCOS/DPI Min/Max
Min.
≥ -2 31
Max. ≤ +2 31
- 1
SERCOS/DPI Scaling Resolution
Scaling type: parameter 76
Scaling factor: parameter 77
Scaling exponent: parameter 78
Rotational position resolution: parameter 79 Units
parameter
76