Rockwell Automation 57C422B 2 Axis Servo Module - Manual (Page 41)

PROGRAMMING 4-13
4.17 Registers 19, 20: Command Velocity
Registers 19, 20 contain the command velocity. This value is
read by the module whenever the following commands are
issued: "index/move", "home axis", "tune dynamics", "tune
feedforward", or "change velocity" in R66; or "velocity
control" in R65. The command velocity units are:
(encoder counts/sec)*65.536
The maximum speed that can be programmed is 65,536,000
counts/sec.
4.18 Registers 21, 22: Command
Acceleration
Registers 21, 22 contain the command acceleration. This
value is read by the module whenever the following
commands are issued: “index/move", "home axis", "tune
dynamics", or "tune feedforward" in R66; or "velocity control"
in R65. The command acceleration is calculated as follows:
acceleration = (eng units/sec/sec)*(encoder counts/eng units)*.065536
The maximum programmed value is 3.28 x 10 10 encoder
counts/sec/sec. The acceleration rate and deceleration rate
(R23, 24) do not need to be equal. However, the deceleration
rate must not be less than one-fifth the acceleration rate.
Figure 4.16 – Command Velocity Registers