ElmoMC SimplIQ Digital Servo Drives-Bell Command Reference - Manual (Page 235)

The controller filter is poorly tuned. In this case, the motor torque may oscillate wildly at
high frequency, but the motor will barely move.
Indications of such situations include:
High average motor torque
Stationary or hardly moving motor
A stationary motor responding to a high torque command does not always indicate an
error. In certain applications, such as thread fastening, it is perfectly legitimate for the
motor to reach a mechanical motion limit.
The drive user should define whether a high-torque stopped motor is a fault or not. If the
parameter CL[2] is less than 2, a high torque that does not lead to motion is not
considered a fault. If the parameter CL[2] is 2 or more, a high-torque stopped motor,
detected for at least 3 continuous seconds, is considered a fault. The motor is set to off
(MO=0) and the fault is MF=0x200,000. The time constant of 3 seconds is used because
almost every motion system applies high torques for short acceleration periods while the
speed is slow.
CL[2] defines the tested torque level as a percentage of the continuous current limit
CL[1]. CL[3] states the absolute threshold main sensor speed under which the motor is
considered not moving. CL[3] should not be set to a very small number because when a
motor is stuck, a vibration may develop so there will be non-zero speed-reading. When
an encoder wire is damaged, the encoder readout is vibrating + bit. This also creates
speed-reading.
Example:
If
CL[2]=50
and
CL[3]=500
, the drive will abort (automatic MO=0) if the torque level is
kept at at least 50% of the continuous current, while the shaft speed did not exceed 500
counts/second for a continuous 3 seconds.
5.2.2 Commutation Faults
5.2.2.1 Matching the Hall Sensors with an
Incremental Position Sensor
If both an incremental sensor and digital Hall sensor are available for commutation
(CA[17]=1), then
SimplIQ will continuously check that both the sensors are consistent.
The Hall sensors provide a rough, but direct, estimate of the commutation angle. The
encoder provides high-resolution data, but it may accumulate errors if the drive setup
data is set incorrectly or if it is faulty.
If the commutation angle derived from the encoder is more than 15 electrical degrees out
of the range of Hall sensor reading
7 , SimplIQ increments an error counter. If the readings
match, the error counter is reduced.
7 Digital Hall sensors resolution is only 60 electrical degrees.
SimplIQ for Steppers Application Note Commutation and Pole Identification
MAN-STECR (Ver. 1.1)
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