Rockwell Automation 57C422B 2 Axis Servo Module - Manual (Page 48)

4-20 2-Axis Servo Module M/N 57C422B
in register 0 (Encoder Setup). This value is read by the
module whenever the "home axis" or "change default setup"
commands in register 66 are issued. The unwind constant is
equal to the number of encoder counts per axis revolution.
Use the same formula in the gearing unwind constant and
the feedback unwind constant. See section 4.27 above for
the formula.
4.29 Register 38: Gearing Modes, Ratio
Format, Ramp Velocity
Control
Register 38 is used to determine gearing mode if bit 9 in
register 65 is not set (0), to select the gear ratio format, and
to enable ramp velocity control. Note that changes to
registers 38
will be ignored while gearing mode is enabled in
register 65 . See figure 4.28.
Figure 4.27 – Gearing Unwind Constant Registers
Figure 4.28 – Gearing Mode, Ratio Format, and Ramp Velocity Control Register