Parker AC890PX Series, Engineering Reference

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D-174
A p p e n d i x D : P r o g r a m m i n g
AC890PX AC Drive
ZERO SPEED
SETUP::MOTOR CONTROL::ZERO SPEED
This function block detects when the motor speed is at or close to zero. HYSTERESIS and THRESHOLD are user-definable.
Parameter Descriptions
HYSTERISIS PREF: 85.01 Default: 0.10 % Range: 0.00 to 300.00 %
Provides a hysteresis band about which the outputs are stable.
IF the hysteresis value is >= to the Threshold
THEN the level is set to 2 x the hysteresis value and the Off level is set to zero,
ELSE the On level = Thr Hysteresis and the Off level = Threshold - Hysteresis.
THRESHOLD PREF: 85.02 Default: 0.50 % Range: 0.00 to 300.00 %
The nominal level below which the outputs are set.
AT ZERO SPD FBK PREF: 85.03 Default: TRUE Range: FALSE / TRUE
Speed feedback. TRUE when at zero speed feedback, as defined by THRESHOLD and HYSTERESIS.
IF (abs(speed feedback)) > On Level at zero speed = FALSE
ELSE if (abs(speed feedback)) <= Off Level at zero speed = TRUE
ELSE at zero speed is unchanged
AT ZERO SPD DMD PREF: 85.04 Default: TRUE Range: FALSE / TRUE
Speed demand. TRUE when at zero speed demand, as defined by THRESHOLD and HYSTERESIS.
AT STANDSTILL PREF: 85.05 Default: TRUE Range: FALSE / TRUE
TRUE when both AT ZERO SPD FBK and AT ZERO SPD DMD are TRUE.