Rockwell Automation 1771-QC , D17716.5.25 SER/B SERVO POS - Manual (Page 48)

Hardware Description
Chapter 5
5Ć11
Because this feature adjusts the position register to the closest even
multiple of the number of feedback increments per revolution, it is
essential that the axis move less than half an encoder revolution per servo
sample period (2.4ms). Therefore, to avoid a programming error, you
must limit the axis speed to conform to this formula:
programmed
axis speed
<
12,500
1.28
x FR x FM x EL
Where:
FR = feedback resolution
FM = feedback multiplier (1, 2, or 4)
EL = encoder lines per revolution
Here is a list of specifications for the servo positioning assembly.
Servo Output Voltage
+10V dc maximum (isolated)
D/A Converter (DAC)
Signed 12 bit resolution
Encoder Input
High: 1.6V
Low: 1.0V sinking lmA
Encoder Input Rate
Differential: 250k Hz maximum
Single-ended: 20k Hz maximum
Jumper selection of differential or single ended input
Encoder Multiplier
x1, x2, or x 4,programmable
Tachometer Input (For loss-of-feedback detection)
Full scale voltage: 3V dc minimum, 50V dc maximum
Input impedance: 20k ohmss
Discrete Inputs
Specifications