Using "Homing" (hm) mode of operation

A reference travel process will be performed on the axis as set out in the reference travel type (homing method).

The reference travel type (see Supported modes of operation) can be set:

  • Via the PDO interface
  • Via SDO parameter services
  • To do this, write the corresponding value from the assignment table to index 24728.0 dec (0x6098/0x7098) (see Object list)
  • During startup via the MOVISUITE® engineering software
  • When you start a reference travel in manual mode of MOVISUITE®, the currently parameterized reference travel type is performed.

INFORMATION

The reference travel type that you set in the PDO interface overwrites the value of the reference travel type that was set in the MOVISUITE® engineering software or written via the SDO parameter service.

The following table shows the CiA402 objects which are required or recommended for the mode of operation. The objects do not absolutely have to be located in the cyclic PDO image.

Note the maximum number of 8 entries in the cyclic PDO image (see Adapting the PDO image).

Control

Feedback

Mode of operation

Mode of operation display

Control word

Status word

Homing method

 

Homing speeds

 

Homing acceleration

Home offset

Setting the mode of operation via the PDO interface is described below.

Proceed as follows:

  • You have successfully started up the motor.
  • You have integrated the inverter into the TwinCAT project via network scan or offline from the device catalog, linked it to a motion axis (see Motion axis: Integrating inverters) and transferred the corresponding process data object to the PDO image (Adapting the PDO image).
  1. Set hm in the "Modes of operation" process data object. Enter the value "6" in the editor window.
    • The "Modes of operation display" process data object reports back the value "6".
    • The value "11" is displayed on the display element of the inverter.
  2. Set the reference travel type in the "Homing method" process data object. The operating principle of the reference travel types corresponds to the operating principle of the reference travel types that you can select in MOVISUITE® via the "FCB 12 Reference travel" drive function.
    • The reference travel no longer has to be started separately, since the corresponding bit in the control word ("Control word" process data object) is already set.

    INFORMATION

    If the inverter is operated in an interpolated mode of operation (csp, csv, cst), a lag error builds up in the motion axis during the reference travel. Before you can start the travel process again, the motion axis must be reset. Note that reducing the lag error can lead to an error in speed monitoring.
    The lag error does not occur with the pp and pv modes of operation where the closed loop system on the inverter is closed.
    • If homing has been performed successfully, the "Homing attained" bit is reported in the status word ("Status word" process data object).
Additional information