PD4-EB EtherCAT Online Manual

Limitation of the range of motion

The digital inputs can be used as limit switches, as is described in chapter Digital inputs, if you activate this function for the inputs. The controller also supports software limit switches.

Behavior upon reaching the limit switch

If a limit switch is triggered, the limit switch position is stored internally, bit 7 (Warning) in 6041h (statusword) is set and the action stored in object 3701h is executed (see following table).

Value in object 3701h Description
-2 No reaction, discard the limit switch position
-1 (factory settings) No reaction (e. g., to execute a homing operation) except noting the limit switch position
0 Switch off driver without deceleration ramp; drive function blocked – motor can turn freely (Switch on disabled state)
1 Braking with slow down ramp (deceleration ramp depending on operating mode) and subsequent state change to Switch on disabled
2 Braking with quick stop ramp and subsequent state change to Switch on disabled
5 Braking with slow down ramp (deceleration ramp depending on operating mode) and subsequent state change to Quick stop active; control does not switch off and the motor remains energized. You can switch back to the Operation enabled state.
6 Braking with quick stop ramp and subsequent state change to Quick Stop Active; control does not switch off and the motor remains energized. You can switch back to the Operation enabled state.

Continued travel behind the limit switch position is prevented provided the value in 3701h is not "-1" or "-2". In any case, it is possible to move in the opposite direction.

If the value "-2" is used, bit 7 in 6041h (Warning) is deleted as soon as the limit switches no longer trigger. Otherwise, it is not deleted until the internally noted limit switch position has been returned to.

Note: To avoid automatically returning from the Quick stop active state to Operation enabled when using options "5" or "6" — the quick-stop bit (bit 2) in 6040h is not used upon triggering of the limit switches — a change of the quick-stop bit from "0" to "1" is expected in order to changed back to the Operation enabled state.

Discarding the limit switch position

Note: It is necessary to discard the limit switch positions if both limit switches were actuated simultaneously or the movement range is dynamically limited by a shifting of the limit switches.

To delete internally stored limit switch positions in the event of triggering and to release or clear the limit switches, briefly set object 3701h to "-2".

If, when using the values "5" or "6" in 3701h, the state of the State Machine is Quick stop active and the motor is to remain energized, proceed as follows to avoid an automatic change to the Switch on disabled state:

  1. Use a rising edge of bit 2 (quick stop) in 6040h to switch back to the Operation enabled state without, however, starting a movement (set bit 4 in 6040h to 0 or target speed or target torque to "0").
  2. Set 3701h to "-2" .
  3. Release the limit switch again.
  4. Reset 3701h back to "5" or "6".

Software limit switches

The controller takes into account software limit switches (607Dh (Software Position Limit)). Target positions (607Ah) are limited by 607Dh; the absolute target position may not be larger than the limits in 607Dh. If the motor is located outside of the permissible range when setting up the limit switches, only travel commands in the direction of the permissible range are accepted.

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