Technical data

Drive functions
7.1 Servo control
Function Manual
150 Function Manual, 06/2012, 6SL3097-4AB10-0BP4
Behavior once pulses have been canceled
Once the pulses have been canceled in operation without an encoder, the current actual
speed value of the motor can no longer be calculated. Once the pulses are enabled again,
the system must search for the actual speed value.
p1400.11 can be used to parameterize whether the search is to begin with the speed
setpoint (p1400.11 = 1) or with speed = 0.0 (p1400.11 = 0). Under normal circumstances,
p1400.11 = 0 because the motor is usually started from standstill. If the motor is rotating
faster than the changeover speed p1755 when the pulses are enabled, p1400.11 = 1 must
be set.
If the motor is rotating and the start value for the search is that of the setpoint (p1400.11 =
1), the speed setpoint must be in the same direction as the actual speed before the pulses
can be enabled. A large discrepancy between the actual and setpoint speed can cause a
malfunction.
WARNING
Once the pulses have been canceled, no information about the motor speed is available.
The computed actual speed value is then set to zero, which means that all actual speed
value messages and output signals are irrelevant.
Switchover between closed-loop/open-loop operation and operation with/without encoder
Operation without an encoder is activated via parameter setting p1300 = 20. If p1300 = 20 or
p1404 = 0, operation without an encoder is active across the entire speed range. If the
speed value is less than the changeover speed p1755, the motor is operated in accordance
with the current/frequency.
During operation with an encoder, a switchover can be made to operation without an
encoder when the speed threshold p1404 is exceeded. If p1404 > 0 and p1404 < p1755, a
switchover to operation without an encoder is not made until the speed exceeds p1755.
Operation without an encoder is displayed in parameter r1407.1.