Rockwell Automation 8520-ARM2 9/Series CNC AMP Reference Manual Documentation Set - Manual (Page 177)

Servo Parameters
Chapter 7
7-31
Function
This parameter places an upper limit on following error for a servo. When
the magnitude of the following error exceeds the value entered here, the
control goes into E-Stop. The error message EXCESS FOLLOWING
ERROR appears on the message line of the control.
ATTENTION: This parameter plays a significant role in
machine safety, as it can prevent damage and injury resulting
from mechanical or electrical failure of a servo.
The smaller the value for this parameter, the sooner the control detects a
servo problem and goes into E-Stop. However, too small a value here
interferes with normal axis motion.
Important: To avoid a Warning: ”SERVO AMP FE LIMITS
CORRECTED”: Inposition Band < Gain Break Point < Feedrate
Suppression Point £ Excess Error
Axis Parameter
Number
Axis Parameter
Number
(1) [1750] (9) [9750]
(2) [2750] (10) [10750]
(3) [3750] (11) [11750]
(4) [4750] (12) [12750]
(5) [5750] (13) [13750]
(6) [6750] (14) [14750]
(7) [7750] (15) [15750]
(8) [8750]
Range
0 to 214.10000 mm or 0 to 8.42913 in. (linear axes)
0 to 1440.0000 degrees (closed--loop spindles)
0 to 214.00000 degrees (rotary axes)
Notes
This parameter must be set independently for each servo.
A typical value is 110% of the maximum following error expected during
operation of an axis. This can be determined by the following equation:
(maximum rapid speed) (1.1)
Min. Excess Error = ------------------------------------------
(Initial Gain) (1000) (Gain Break Ratio)
On closed--loop spindle applications, this parameter is only applied to the
servo while the spindle is orienting or tapping.
7.2.4
Excess Error