Siemens SINAMICS G120XA, Operating Instructions Manual

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Note
Bits 0 ... 2 only have an influence for sensorless vector control, bit 2 is pre-assigned depending on p0500.
For bit 2 = 1:
The sensorless vector control is effective down to zero frequency. A change is not made into the open-loop speed
controlled mode.
This operating mode is possible for passive loads. These include applications where the load itself does not generate
any active torque and therefore only acts reactively to the drive torque of the induction motor.
If bit 2 = 1, then bit 3 is automatically set to 1. Manual de-selection is possible and may be sensible if the saturation
characteristic (p1960) was not measured for third-party motors. Generally, for standard SIEMENS motors, the already
pre-assigned (default value) saturation characteristic is adequate.
When the bit is set, the selection of bits 0 and 1 is ignored.
For bit 2 = 0:
Bit 3 is also automatically deactivated.
For bit 6 = 1:
The following applies for sensorless vector control of induction motors:
For a blocked motor (see p2175, p2177) the time condition in p1758 is bypassed and a change is not made into open-
loop controlled operation.
For bit 7 = 1:
The following applies for sensorless vector control of induction motors:
If the changeover limits are parameterized too low (p1755, p1756), then they are automatically increased to rugged
values by the absolute amount p1749 * p1755.
The effective time condition for changing over into open-controlled operation is obtained from the minimum value of
p1758 and 0.5 * r0384.
Is recommended that bit 7 is activated for applications that demand a high torque at low frequencies, and at the same
time require low speed gradients..
Adequate parameterization of the current setpoint must be ensured (p1610, p1611).
For bit 8 = 1: no influence on the functionality of bits 0, 1, 2
The following applies for sensorless vector control of induction motors:
Changeover into open-loop speed controlled operation is no longer dependent on the speed setpoint (except for
OFF3), but instead is essentially dependent on time condition p1758. As a consequence, a drive can be started or
reversed in closed-loop speed controlled operation with setpoints from an external control system, if these briefly lie in
the open-loop speed control range.
p1755[0...n] Motor model changeover speed encoderless operation / MotMod n_chgSnsorl
Access level: 3 Calculated: CALC_MOD_REG Data type: FloatingPoint32
Can be changed: T, U Scaling: - Dynamic index: DDS, p0180
Unit group: 3_1 Unit selection: p0505 Function diagram: -
Min:
0.00 [rpm] Max:
210000.00 [rpm] Factory setting:
210000.00 [rpm]
Description: Sets the speed to change over the motor model to encoderless operation.
Dependency: See also: p1756
NOTICE
The changeover speed represents the steady-state minimum speed up to which the motor model can be used in
sensorless steady-state operation.
If the stability is not adequate close to the changeover speed, it may make sense to increase the parameter value. On
the other hand, very low changeover speeds can negatively impact the stability.
Note
The changeover speed applies for the changeover between open-loop and closed-loop control mode.
Parameters
7.3 Parameters
SINAMICS G120XA converter
Operating Instructions, 03/2019, FW V1.0, A5E44751205B AB
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