Siemens SIMATIC S7-300 Manual page 249

Following error Axis standstill
monitoring
A message is output on an axis standstill setpoint or deactivated servo enable
if disturbances cause the axis to move out of position.
26
The standstill zone is located symmetrically around the target approach posi-
tion.
When the tolerance window for idle is exceeded, the FM 354 signals a "Sta-
tionary Range" error (see Troubleshooting, Table 11-5,
Class 1/No. 12).
Axis moving
To monitor following error during movement, the FM 354 calculates the al-
lowable following error for the instantaneous traveling speed from the para-
meterized positioning loop amplification (MD38). Above the parameterized
"Minimum following error (dynamic)," a comparison is performed with the
actual value for the following error.
MD39
∆s – following error
39
When the calculated following-error limit is exceeded, the FM 354 signals a
"Following error too great" error (see Troubleshooting, Table 11-7,
Class 3/No. 66).
Exception:
If an axis standstill occurs above the "minimum dynamic following error",the
error message described under Basic diagnostics "no drive movement" is
output (see Table 11-7, Class 3/No. 65).
FM 354 Servo Drive Positioning Module
MD Designation
Stationary range 0...1 000 000
Approach position
Stationary range
Calculated curve of following
error (∆s
∆s
Dynamic
monitoring in
effect
Actual curve of following error
v – speed
MD Designation
Minimum following error (dy-
namic)
Description of Functions
Value/Meaning
[MSR]
)
calc
(Idealized) curve of following
error
v (MD23)
max
Value/Meaning
0 = no monitoring
0...100,000
Unit
v
Unit
[MSR]
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