Firmware ≤ 05.00 - DMS 4.2 EN - 02/2010 L 447
8400 HighLine | Parameter setting & configuration
Basic drive functions (MCK)
Holding brake control
8.12.2.6 Ramp times for approaching the setpoint speed
For the "Speed follower
" operating mode, a ramp time can be set in C02610/1 if the
setpoint is already out of reach while the holding brake is initiating the feedforward
control process.
Example:
A setpoint of 90 % is selected via the ramp function generator while the brake is applied
(controller is inhibited).
1. At the set ramp (in most cases C00012
), the ramp function generator ramps up to 90 %.
2. The brake identifies the setpoint selection of 5 % (release switching threshold). The
feedforward control of the brake provides 3 % of the setpoint and will not report the
release of the brake after approx. 1 s has expired.
Conclusion:
90 % of the selected setpoint is already ramped up while the brake is only
providing 3 % of the setpoint via the feedforward control.
Since at this point a step change from 3 % to 90 % may cause mechanical jerks, the setpoint
is ramped up from 3 % to 90 %, using the ramp time set in C02610/1
(Lenze setting: 2 s).
Our example is based on the V/f characteristic control (VFCplus) operating mode since the
servo control (SC) operating mode does not use the switching threshold for the application
of the holding brake for speed feedforward control. However, ramping up to a setpoint
that is out of reach is carried out for all motor control operating modes because there is
always a mechanical/electric delay when controlling a holding brake.
This delay is due to:
Motor magnetisation (in case of servo control only)
Mechanical delay of all switching elements connected upstream to the holding brake
Mechanical delay of the holding brake itself
Generation of the holding torque by the motor
Note!
The "Homing", "Manual jog", and "Positioning" operating modes are based on a
different control/release process of the holding brake. In these operating modes,
the C02610/1
setting parameter does not have any effect!
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