KEB COMBIVERT F5-A Applications Manual page 397

Bit Meaning
0 1: LA stop
2: Deceleration
1
stop U-abh.
4: deceleration
2
stop I-dep.
In the operating modes positioning or synchronous running, this function is not active. If a ramp time is entered
in Pn.60 for abnormal stopping, the deceleration stop is active.
7.13.7.1 Current-dependent ramp stop
In v/f-characteristic operation, overcurrent errors can occur due to short ramps.
Therefore, a current limit can be programmed with Pn.24 "ramp stop current level" that is frozen on exceeding
the ramp generator output value(ru.02).
In closed-loop operation the current is limited in software via the control-internal current and torque limits.
Therefore the functions acceleration stop (LA-Stop) and current-dependent deceleration stop (LD-Stop (I)) are
useless.
Value Explanation
0 .. 200% Current level at which the ramp is stopped
If the acceleration stop in speed-controlled operation is active in order to use the interruption of the ramp via
digital input, the current level in Pn.25 must be set to 200% to avoid negative effects.
7.13.7.2 DC link voltage-dependent ramp stop
The LD-Stop (U) function can be used to prevent overvoltage errors during deceleration.
During deceleration energy is refeed into the frequency inverter, which causes a rise of the DC-link voltage.
If too much energy is recovered, the inverter can switch to overvoltage (OP) error.
If the LD-Stop (U) function is activated with Pn.22, the DEC-ramp is stopped when the current DC link voltage
(ru.18) exceeds the adjusted LD voltage (Pn.25).
Value
200V...1200V DC-link voltage level at which the ramp is stopped
Overvoltage errors cannot always be securely prevented with this protection function, because after setting
the ramps and the speed controller, further deceleration can occur despite stopping the ramp. If the drive
decelerates, e.g., at the torque limit, and can therefore not follow the ramp, it does not help to stop this ramp.
An undershoot of the speed controller due to a sudden termination of the ramp can also lead to further energy
recovery in the DC link.
Generally, the deceleration process is slowed down by this protection function. The use of a braking resistor is
necessary for a dynamic deceleration.
© KEB, 2012-10 COMBIVERT F5-A, -E, -H
Pn.22: Ramp stop activation
Explanation
The acceleration ramp is stopped if Pn.24 "LAD load level" is exceeded or if the
input programmed in Pn.23 "LAD stop input selection" is set
The acceleration ramp is stopped if Pn.25 "LD voltage" is exceeded or if the input
programmed in Pn.23 "LAD stop input selection" is set
The deceleration ramp is stopped if Pn.24 "LAD load level" is exceeded or if the
input programmed in Pn.23 "LAD stop input selection" is set
Explanation
Protective functions
Pn.25: LAD load level
Pn.25: LD voltage
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