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Using AKD in a Vertical Axis

Note: For firmware versions 1-06 and later.

The drive should be configured to execute a controlled stop action in the event of a disable command (DRV.DISMODE = 2 or 3). This allows the motor to stop and the brake to be applied before the drive stops holding up the axis and removes power. With a vertical axis application where the motor is equipped with a brake that is controlled by AKD, it is recommended to set up the axis to immediately apply the brake in the event of the power stage disabling for any reason. By setting MOTOR.BRAKEIMM = 1 (default is 0=off) the brake will apply immediately when the power stage is disabled.

The power stage can disable as a result of:

  • Hardware Enable removed
  • Software Enable removed
  • Safe Torque Off (STO) activated
  • Fault Condition
  • Controlled Stop Input – any input configured as (DINx.MODE = 13 controlled stop)

If the vertical axis is stationary and disabled, toggling the brake with MOTOR.BRAKERLS will not reapply the brake until controlled stop conditions are met (the axis actual velocity has been less than CS.VTHRESH for CS.TO milliseconds). In order for the brake to reapply immediately when commanding MOTOR.BRAKERLS, set CS.VTHRESH to a value greater than the velocity possible by the free falling axis and set CS.TO to 1 millisecond (its minimum value) prior to making the command.

Note: For a digital input initiated controlled stop (A fault that results in controlled stop. See Fault and Warning Messages), or a software disable that is configured for a controlled stop (see DRV.DISMODE), the brake will be applied at the end of the controlled stop when the power stage disables.

It is still important to setup the brake delays. This can be done in the brake screen under the settings section in WorkBench. These brake delays are used to delay the disabling of the power stage when motion is stopped and the drive is disabled. This is only pertinent for Controlled Stop and Software Disable of the drive. This prevents a slight drop of the load between the disable and the brake engagement. In other cases, (Fault, Hardware Enable, STO) hardware disconnection prevents the AKD from delaying the disable.

There is an advanced setting for the Hardware Disable. A programmable delay is available on the HW Enable input so the drive can hold the load before the disable. With a vertical load some movement could occur when the drive is disabled with a hardware input because the power stage was disabled immediately, before the brake could apply. DRV.HWENDELAY is available which will delay the disabling of the power stage. During this delay time, the drive will apply the brake immediately and simultaneously attempt to follow normal disable procedures. The value is limited to a maximum of 167 ms. During this time, the drive will attempt to bring the load velocity to 0 RPM. If DRV.HWENDELAY = 0, the feature is off (this is default).

Vertical Application Desired Response Customer Disable Condition Configuration Needed Parameter Settings Needed
Controlled stop when possible. If not possible, apply motor brake immediately. Normal disable Command CS using input. Do not disable power stage or command other disables until CS completes. DRV.DISMODE = 2. Controlled stop then disable. Set: DRV.DISTO CS.VTHRESH CS.DEC CS.TO .
E-stop, or safety condition
Fault CS Do not disable power stage or command other disables until CS completes.
Fault Dynamic Brake N/A N/A
Fault Power stage disable None MOTOR.BRAKEIMM = 1
Controlled stop when possible. If not possible, dynamic brake. Normal disable Command CS using input. Do not disable power stage or command other disables until CS completes. DRV.DISMODE = 3. Controlled stop, then dynamic brake. Set: DRV.DISTO CS.VTHRESH CS.DEC CS.TO .
E-stop, or safety condition
Fault CS Do not disable power stage or command other disables until CS completes.
Fault Dynamic Brake N/A N/A
Fault Power stage disable None MOTOR.BRAKEIMM = 1

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Frank Peifer's picture
Frank Peifer
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