ElmoMC SimplIQ Software Manual - Manual (Page 207)

SimplIQ Software Manual Limits, Protections, Faults and Diagnosis
MAN-SIMSW (Ver. 1.4)
13-12
13.10 Sensor Faults
13.10.1 Motor Cannot Move
When the motor is unable to complete a command to move, the reasons may be:
ƒ
The motion sensor is faulty: The motor moves but motion is not detected. In this case,
AC motors will generally stop, because the stator field will remain stationary.
ƒ The motor is faulty or another mechanical failure is preventing the motor from
moving.
ƒ 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:
ƒ
High average motor torque
ƒ Stationary motor or very slow motor movement
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 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 that will induce speed-reading. When an encoder
wire is damaged, the motor will run away with the encoder readout vibrating + bit. This
also creates speed-reading.
Example:
If CL[2]=50 and CL[3]=500, the drive will abort (reset to MO=0) if the torque level is kept
at at least 50% of the continuous current, while the shaft speed does not exceed 500
counts/second for a continuous 3 seconds.