Rockwell Automation 8520 9/Series Hardware TAB 5 - Manual (Page 101)

Section 5B
9/440HR CNC/Drive System
5B-27
Maximum Axis Speed Use the following equation to determine the maximum axis speed. Note that this equation does not take
into consideration any mechanical deficiencies in the encoder or motor. It is only concerned with the
9/Series capability of receiving feedback. Refer to the manufactures specs for encoder and motor
hardware RPM limitations.
(ECF x 60)
---------------- = Maximum Axis Speed
(E) (N) (P)
Where:
Max Axis Speed = Maximum Axis Speed based on encoder feedback (inches or millimeters per minute)
ECF = Maximum encoder channel frequency the control may receive in units of cycles/sec.
E = the number of encoder lines between markers for your encoder
E = 1024 sin/cos cycles per revolution for HR Single–turn Absolute (SinCoder)
E = 512 sin/cos cycles per revolution for HR Multiturn Absolute (SinCos)
N = the ratio of encoder turns to ballscrew turns
P = the ballscrew pitch (turns per inch or turns per millimeter. For rotary axes, substitute the appropriate
gear ration for N and P in the equation above to solve for a max RPM in revolutions per minute.
If the maximum axis speed resulting from this equation is less than you would like, you may need to
sacrifice some axis resolution by selecting an encoder with fewer lines between markers.
Input Signal Encoder feedback must be differential format with 5V–compatible (9.7V for HIPERFACE feedback devices)
output signals, single-ended open-collector outputs are not supported, i.e., channels A, B, and Z must
have source and sink current capability, 8830 line driver outputs or equivalent.
Current Drawn from Encoder by
Servo Module 20 mA maximum; 50 mA peak/differential output 1
Marker Channel Narrow (gated), Wide (ungated), and Distance–coded type markers are supported.
Encoder Cable Length Refer to chapter 7 for details on cabling.
1 Applies to A quad B feedback ports (J9 – J12) only. Current drawn is rated for each channel (A and B) output.