Rockwell Automation 8520-ARM2 9/Series CNC AMP Reference Manual Documentation Set User Manual
Page 314

Acc/Dec Parameters
Chapter 10
10-18
The value entered here indicates the number of “coarse iterations” that
make up an Acc/Dec time constant. A coarse iteration is one of the
control’s software timing cycles and is equal to one system scan time. The
Acc/Dec time constant represents the amount of time required to accelerate
or decelerate 63% of the way to the commanded speed (refer to
Figure 10.1).
For all practical purposes, acceleration or deceleration is completed after
five time constants. Therefore, the total acceleration or deceleration time
can be determined by multiplying the value entered here first by the system
scan time, and then by 5.
Refer to the notes for the parameter Manual Delay Constant for more
application information and examples. The equations provided there can
be applied here if the variable Manual Delay Constant is replaced with
Programmed Delay Constant.
This is not a per axis parameter. The delay constant selected here is
applied to all axes.
Axis
Parameter Number
Single Process
Process 1
Process 2
All
[8]
[20008]
[21008]
Range
1 to 100
Notes
This is a global parameter. The value set here applies to all axes.
For Dual Processing controls, this is a per process parameter. The value set
in the parameters applies to all of the axes assigned to that process.