Rockwell Automation 57C422B 2 Axis Servo Module - Manual (Page 47)

PROGRAMMING 4-19
insure that the velocity output is linearly related to the
number computed by the software. Initially, this value should
be set to -1. The "tune dynamics" command in register 66 will
adjust this number if the drive has been configured as a
velocity regulator.
4.27 Registers 34, 35: Feedback Unwind
Constant
Registers 34, 35 contain the unwind constant for the
feedback encoder. Refer to figure 4.26. This parameter is
used in the rotary mode selected in register 0 (Encoder
Setup). This value is read by the module whenever the
"home axis" or "change default setup" commands (register
66) are issued. The unwind constant is equal to the number
of encoder counts per axis revolution. Use the following
equation to determine the unwind constant:
Unwind Constant = encoder counts/rev * encoder revolutions
axis revolution
4.28 Registers 36, 37: Gearing Unwind
Constant
Registers 36, 37 contain the unwind constant for the gearing
encoder. This parameter is used in the rotary mode selected
Figure 4.25 – Positive Linearization Constant Register
Figure 4.26 – Feedback Unwind Constant Registers