Current limiting – ElmoMC SimplIQ Digital Servo Drives-Bell Command Reference User Manual

Page 232

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Command Description

IL[N]

Input logic. Defines digital inputs as stop and limit switches.

LC

Limit current indication that indicates whether peak limit is active.

LL[N]

Protection low limits for position and speed feedback.

MF

States reason for a motor automatic shutdown.

OL[N]

Output logic. Programs digital outputs as brake activation or as
drive ready indication.

PL[N]

Peak current limit.

PS

Program status.

SR

Status register. Gives

SimplIQ

drive status, including if motor is shut

down by exception or if a Stop switch has been hit.

VH[N]

Command high limits for position and speed reference.

VL[N]

Command low limits for position and speed reference.

Figure 5-1: Commands Relevant to Limits, Protection and Diagnosis

CANopen offers an additional protection level: emergency objects issued in cases

of errors or applied protections (refer to the Elmo CANopen Implementation Manual).

5.1. Current

Limiting

The drive protects the motor from over-current using a two-stage method. The motor
maximum peak current (given by PL[1]) is available for the peak duration time (specified
by PL[2]), while for longer periods, the current is limited to its continuous limit (CL[1]).

The current limiting process is dynamic: If the current has been close to its continuous
limit, the time allowed for the peak current is reduced.

The following block diagram shows the current limiting mechanism:

SimplIQ for Steppers Application Note

Commutation and Pole Identification

MAN-STECR (Ver. 1.1)

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