Rockwell Automation 8720MC Drives Integration Manual - Manual (Page 127)

Publication 8720MC-IN002A-EN-P — December 2002
Programming Parameters C-15
Name: -Vel_Limit_0 Data Display: Signed Decimal R/W
Parameter No.
39
File:
Servo Loop
Group:
Group 0 Description: Negative velocity limit value. This parameter describes the maximum allowable velocity in the
negative direction. If the velocity limit value is exceeded, the drive responds by setting the status 'ncommand >
nlimit' in C3D (see parameter 13) as well as parameter 335 “Vel_Above_Limit”. This parameter appears in 8 sets
of servo loop parameters. Parameter 39 appears in Group 0. See Parameter Files, Groups, and Elements (Group
Listing) in this chapter. The commanded negative RPM will be limited to this value. If for any reason the actual
motor velocity exceeds - Vel_Limit_0 by 50% an overspeed fault will disable the drive.
Default:
-6000 Length
2 bytes SCANport Min/Max
Min.
≥ -30,000
Max. ≤ 0
SCANport Scaling Resolution
1 = 1RPM Units
RPM
Default:
-6000 Length
4 bytes SERCOS/DPI Min/Max
Min.
≥ -2 31
Max.
≤ 0
SERCOS/DPI Scaling Resolution
Scaling type: parameter 44
Scaling factor: parameter 45
Scaling exponent: parameter 46 Units
parameter
44
Name: Velocity_Fback Data Display: Decimal R, Link
Parameter No.
40
File:
Control
Group:
Velocity Description: The velocity feedback value. In the SERCOS configuration the velocity feedback value is transferred
from the drive to the control unit in each AT cyclic telegram in order to allow the control unit to have access to the
actual velocity. In both the analog and SERCOS configurations the motor encoder supplied velocity feedback is
used to close the velocity loop. With the suggested feedback and motor wiring a positive velocity reference
produces clockwise rotation when viewed from the shaft end of the motor.
Default:
0 Length
2 bytes SCANport Min/Max
Min.
≥ -30,000
Max.
≤ 30,000
SCANport Scaling Resolution
1 = 1RPM Units
RPM
Default:
0 Length
4 bytes SERCOS/DPI Min/Max
Min.
≥ -2 31
Max.
≤ +2 31
- 1
SERCOS/DPI Scaling Resolution
Scaling type: parameter 44
Scaling factor: parameter 45
Scaling exponent: parameter 46 Units
parameter
44