Rockwell Automation 8720MC Drives Integration Manual - Manual (Page 132)

Publication 8720MC-IN002A-EN-P — December 2002
C-20 Programming Parameters
Name: Posn_Polarity Data Display: Bit Pattern R/W
Parameter No.
55
File:
Control
Group:
Position Description: Position polarity parameters. This parameter is used to switch polarities of reported position data for
specific applications. Polarities are switched outside (i.e. on the input and output) of a closed loop system. The
motor shaft turns clockwise (when viewed from the output shaft) when there is a positive position command
difference and no inversion is programmed.
Enumerations:
Structure of the Position polarity parameter:
Bit 0 Position command value
0 = Non-inverted
1 = Inverted
Bit 1 Additive position command value
0 = Non-inverted
1 = Inverted
Bit 2 Position feedback value 1
0 = Non-inverted
1 = Inverted
Bit 3 Position feedback value 2
0 = Non-inverted
1 = Inverted
Bit 4 Position limit values
0 – disabled
1 – enabled
Bit 5: Underflow / Overflow threshold (parameter 280, 281)
0 – disabled
1 – enabled Bits 15-6 (reserved)
This parameter is available with the 8720MC SERCOS interface.
Default:
0 Length
2 bytes SERCOS/DPI Min/Max
N/A SERCOS/DPI Scaling Resolution
N/A Units
N/A
Name: IN_Posn_Value Data Display: Decimal, nnn.nn R/W
Parameter No.
57
File:
Status/Fault
Group:
Setup Description: Position window. When the difference between the accumulated position command value and the
position feedback value is within the range of the position window, then the drive sets the status “in position”
(parameter 336). When needed, the status 'in position' is assigned to a real-time status bit within the drive status
and then transferred to the control unit (see parameter 305).
Default:
10 counts Length
2 bytes SCANport Minimum/
Maximum
Min.
≥ 0
Max.
≤ +30,000
SCANport Scaling Resolution
1 = 1 count/rev as determined by parameter 79,
with parameter 79 set at 3,600 then each count will
equal. 1 degree
e.g. with parameter 79 set for 3600, 2 = .2 degree Units
parameter 79
counts/rev
Default: Length
4 bytes SERCOS/DPI Min/Max
Min.
≥ 0
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