Rockwell Automation 8720MC Drives Integration Manual - Manual (Page 140)

Publication 8720MC-IN002A-EN-P — December 2002
C-28 Programming Parameters
Name: Modulo_Value Data Display: Integer R/W
Parameter No.
103
File:
Control
Group:
Position Description: Modulo value. In the SERCOS configuration if the modulo format is selected in the position scaling
parameter (parameter 76), the modulo value defines the range that the drive & control must implement. This
value determines the roll over point of a modulo axis. In the analog configuration the position data scaling type is
always rotary axis. For example, if a 360 degree roll over point is desired, 3600 must be entered into parameter
103, assuming parameter 79 is set up for a resolution of 3600 counts per revolution. In this configuration the
motor will move from o to 359.9 and roll over to zero in one motor revolution when rotating in the positive
clockwise direction and viewing from the shaft end of the motor. As another example a 7200 count modulo rotary
axis can be set up by entering 7200 in parameter 103 and 7200 in parameter 79. In this case the position
feedback display will rollover after 7200 feedback counts of the motor. As yet another example, a 30,000 count
modulo rotary axis can be set up by entering 30,000 in parameter 103 and 30,000 in parameter 79. In this case
the position feedback will accumulate from 0 to 29999 and rollover back to 0 after 1 revolution of the motor and
the resolution will be one in 30,000. It is always a good practice for applications using orient to set the value of
parameter 103 to the same value as parameter 79, “Rotary Position Resolution”. This assures that an orient from
stand still will take one revolution.
Default:
3600 counts Length
2 bytes Minimum/Maximum
Min.
≥ +1
Max. ≤ +65535
Scaling Resolution
1 = 1 count as determined by parameter 79 Units
param 79
in counts
Default: Length
4 bytes SERCOS/DPI Min/Max
Minimum Input: > 1
Maximum Input:
≤ 2 31
-1
SERCOS/DPI Scaling Resolution
Scaling type parameter 76
Scaling factor parameter 77
Scaling exponent parameter 78
Rotational position resolution parameter 79
Preferred scaling:
–rotational = 1x10-4 degrees
–linear = 1x10-7 m or 1x10-6 in Units
parameter
76
Name: Pos_Loop_Gain_0 Data Display: Decimal R/W
Parameter No.
104
File:
Servo Loop
Group:
group 0 Description: Position loop KV -factor. The KV-factor determines the gain of the position loop regulator throughout
the entire velocity range. Increasing this parameter produces faster position loop dynamic response with higher
risk of instability. It will also reduce the dynamic position error. Decreasing this parameter will soften the
dynamic response, increase the dynamic position error and reduce the position loop instability.
Default:
60 Length
2 bytes Minimum/Maximum
Min. > 0
Max.
≤ 30,000
Scaling Resolution
1 = .01 m/min/mm or .01 in/min/.001 in Units
(m/min)/
mm
Name: Pos_Int_Time_0 Data Display: Decimal R/W
Parameter No.
105
File:
Servo Loop:
Group:
group 0 Description: Position loop integral action time. Increasing this parameter will increase the integration time and
thus reduce the dynamic response. Decreasing this parameter will decrease the integration time and thus
increase the dynamic response.
Default:
6553.5 Length
2 bytes Minimum/Maximum
Min. > .1
Max.
≤ 6553.5
Scaling Resolution
1 = .1 msec Units
msec