Pl[n] - peak duration and limit – ElmoMC SimplIQ Digital Servo Drives-Bell Command Reference User Manual

Page 135

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PL[N] - Peak Duration and Limit

Purpose:

PL[1] defines the motor maximum peak current, in amperes.
PL[2] defines the motor maximum peak duration, in seconds.

This parameter is used to protect the motor (or the drive) from over-current, and to
protect the load from excessive torque. The motor current (torque) command is normally
limited to its peak limit, as defined by PL[1]. After a short period of torque demand
higher than C[1], the torque command limit is decreased to CL[1]. If the current
command has been raised to PL[1] from zero, after the time specified for peak duration
(PL[2], in seconds), the motor current command will be limited to CL[1]. The motor
current command remains limited to CL[1] until enough time has passed for the average
requested torque command to fall below 90% of CL[1].

The LC flag indicates that the current is limited to its continuous limit.

Torque limits PL[N] and CL[N] may be changed dynamically while the motor is on.

Attributes:

Type: Parameter,

Real

Source:

Program, RS-232, CANopen

Restrictions: None
Default values:

PL[1]=0, PL[2]=3 (RS), Non-volatile

Range: PL[1]:

[0…MC]

PL[2]:

[1…3]

Index range: [1,

2]

Unit modes: All
Activation: Immediate
SimplIQ: Modified

Notes:

Always specify a PL[1] value that can be reached. Placing an unreachable PL[1]

can cause the anti-windup mechanism not to work properly, causing large
position overshoots when the drive saturates.

Allowed peak current may be saturated at a level lower than the PL[1] value

when the PWM frequency is increased with the XP[2] command. The actual peak
saturated value in amperes can be retrieved with the WS[33] command. The
option applies only to drives that have the ability to increase the PWM rate.

If CL[1] > PL[1], PL[1] will be the torque limit in effect at all times, and PL[2] will

be ignored.

The minimum current limit is MC/128. If PL[1] < MC/128, the PL[1] value will

be accepted, but the actual current value will be limited to MC/128.

PL[1] is used to determine the maximum and minimum limits for the PWM

generator used for current reference in 50% and 100% PWM mode.

SimplIQ for Steppers Command Reference Manual

Alphabetical Listing

MAN-STECR (Ver. 1.1)

127

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