Setpoint channel and closed-loop control
7.4 Vector speed/torque control with/without encoder
Drive converter cabinet units
Operating Instructions, 07/07, A5E00288214A
275
Note
In this case, the speed setpoint upstream of the ramp-function generator must be greater
than (p1755).
Closed-loop operation up to approx. 1 Hz (settable via parameter p1755) and the ability to
start or reverse at 0 Hz directly in closed-loop operation (settable via parameter p1750)
result in the following benefits:
● No switchover required within closed-loop control (smooth operation, no dips in
frequency).
● Stationary speed–torque control up to approx. 1 Hz.
Note
When the motor is started or reversed in closed-loop control mode at 0 Hz, you must
remember that a switchover is made from closed-loop to open-loop control automatically
if the system remains in the 0 Hz range for too long (> 2 s or > p1758).
Permanent-magnet synchronous motors are always started and reversed in open-loop
operation. The changeover speeds are set to 10% or 5% of the rated motor speed.
Changeover is not subject to any time condition (p1758 is not evaluated). Prevailing load
torques (motor or regenerative) are adapted in open-loop operation, facilitating constant-
torque crossover to closed-loop operation even under high static loads. Whenever the pulses
are enabled, the rotor position is identified.
Function diagram
FD 6730 Interface to Motor Module
Parameter
• p0305
Rated motor current
• r0331
Motor magnetizing current/short-circuit current
• p1610
Torque setpoint static (SLVC)
• p1611
Supplementary accelerating torque (SLVC)
• p1750
Motor model configuration
• p1755
Motor model changeover speed encoderless operation
• p1756
Motor model changeover speed hysteresis
• p1758
Motor model changeover delay time, closed/open-loop control
• p1759
Motor model changeover delay time open/closed loop control
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