● A limit switch has responded.
Consequence:
– Braking at maximum deceleration
In MAN mode, operation of the limit switch is direction-dependent. In all other modes, it
operates independently of the direction of travel.
– Error message E7 (Invalid mode at the limit switch, trolley) in the SAM and POS modes
● An error has occurred.
Note
Travel should be aborted in the PLC in response to all errors that can result in further travel
being impossible, or in response to higher-level errors. These include overload, drive fault,
emergency stop, position sensing errors.
6.8
Acceleration and deceleration behavior
The load sway on container cranes and ship unloaders can be eliminated by influencing the
acceleration and deceleration of the trolley in a targeted manner.
The acceleration and deceleration behavior of the sway control system is set by means of
acceleration values.
The ramp applied in the case of acceleration without sway control / minimum acceleration (P7)
is generally the same ramp-up or ramp-down time required by the drive when sway control is
completely deactivated. The minimum acceleration rate acts as a limit if one of the following
conditions is fulfilled:
● Prelimit switches have been activated
● Velocity reduction due to change in external override
● Sway control is deactivated (control bit SC_ON = 0)
The minimum acceleration is not operative in the normal travel range and when the override
does not change. The sway control system can then decelerate more slowly to compensate any
load sway.
The maximum acceleration (P5) represents a limit in the opposite direction. The sway control
system will never accelerate or decelerate faster than the required ramp-up or ramp-down time.
It should ideally be set to the maximum possible physical value.
The set acceleration (P6) provides the basis for calculating the output velocity of the sway
control. However, in order to compensate for any load sway, the sway control system does not
rigidly adhere to this ramp-up or ramp-down time.
The following settings are recommended:
● P5: The maximum possible acceleration rate of the drive
● P6: 90% of P5
● P7: The following condition applies: P7 < P6 < P5. The specific value is determined by the
position of the prelimit switches relative to the limit switches. The optimum values must then
be determined experimentally on the crane.
Sway Control function description
6.8 Acceleration and deceleration behavior
SC integrated STS, GSU
Operating Instructions, 07/2019, A5E48271265B AA
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