JVL MIS23 Series, User Manual

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JVL Industri Elektronik A/S - User Manual - Integrated Stepper Motors MIS23x, 34x, 43x 71
5.2 Auto Correction
5.2.1 Auto correction
Auto Correction is used in motors with a built-in encoder only. It is only used in position
mode to re-try a movement if the decoder position is too far from the target after the
pulse generator has stopped moving the motor – this will happen for instance if the
movement was physically blocked, the torque of the motor was insufficient, or a bad val-
ue for start velocity or acceleration were used. It might also be used to handle occasional
mechanical oscillations.
The AutoCorrection system will first wait (unconditionally) for a certain time to allow the
initial movement to settle mechanically before testing for the target position. It will then
attempt a normal movement, using the same values for velocities and acceleration as the
movement that failed. It will continue until the encoder position is within the target win-
dow, or the selected number of retries has expired.
Note that AutoCorrection will only start after the value of the P_SOLL register is
changed. In other words, changing P_SOLL (not just writing the same value again) will
reload the maximum number of retries and set the Auto Correction Active status bit.
The Auto Correction Active status bit will remain set until either the position is within
the target window or the max number of retries has been exhausted.
Also note that if the motor is used to control other motors by sending out the pulse and
direction signals on digital outputs, any extra movements caused by AutoCorrection will
send out additional steps to the other motors.
Registers affected:
• Register 33, IN_POSITION_WINDOW, specifies how many steps from the target
position the encoder must report before AutoCorrection is attempted.
• Register 34, IN_POSITION_COUNT, specifies the maximum number of retries. A
value of 0 (zero) effectively disables AutoCorrection.
• Register 110, SETTLING_TIME, specifies the number of milli-seconds to wait after a
movement before testing the encoder position against IN_POSITION_WINDOW.
In the present firmware versions, SETTLING_TIME will be used in AutoCorrection
mode only.
• Register 25, STATUSBITS, will still set bit 4 after the pulse generator has output all
the pulses to reach the target position (a theoretical In-Position). In AutoCorrection
mode, bit 2 will be set to reflect if the internal encoder position is /-
IN_POSITION_WINDOW steps from the target position P_SOLL (a physical In-Po-
sition). Also bit 1 will be set when AutoCorrection is active. Higher layer software
can
use this bit to detect when AutoCorrection has either completed or given up.
• Register 124, SetupBits, bit 1 can be set to have the firmware maintain the InPhysi-
cal Position bit 1 in register 25 all the time, also during a movement. If this bit is not
set, the InPhysicalPosition bit will only be maintained after the motor has stopped
moving.
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Only MISxxx--- H2 ---