An external torque limitation can be selected via the inputs MCTRL-HI/LO-M-LIM. The maximum value to be entered in HI-M-LIM is 199.99 %. The minimum value to be entered in LO-M-LIM is -199.99 %.
MCTRL-HI-M-LIM defines the upper torque limit of the max. torque indicated under code C0057 in [%]
MCTRL-LO-M-LIM defines the lower torque limit of the max. torque indicated under code C0057 in [%]
Functionality in software version < V6.2:
In software versions < V6.2 the torque limits (HI/LO-M-LIM) are evaluated above the reference point (field weakening range: frated < fact) by using the function 1/fact, i.e. the torque is reduced. This reduction is also carried out if a torque limit < 100 % is entered.
Functionality in software versions ≥ V6.2:
A new code (C0898) has been implemented with software version V6.2:
C0898:'M-LIM switch' Evaluation of the torque limit in the field weakening range
C0898 = 0: 'M-LIM ON' HI/LO-M-LIM is evaluated with 1/fact (Lenze setting) which corresponds to the functionality of the software version < V6.2.
C0898 = 1: 'M-LIM OFF' HI/LO-M-LIM is not evaluated with fact. An internal limit characteristic which corresponds to a max. torque limit of +/-199.99 % is evaluated with 1/fact to avoid a stalling of the motor. => Provided that the drive controller provides enough current and that the motor is stall protected in the requested range the torque remains constant until reaching the limit characteristic.
Applications
Applications which require a constant torque, even when operating in the field weakening range, e.g. extruder
Legend of figure:
a = limit characteristic with HI-M-LIM = 199.99 %
0 = upper torque limit with C0898 = 0 and with HI-M-LIM = 80 %
1 = upper torque limit with C0898 = 1 and with HI-M-LIM = 80 %
