# External axis commanding

Activating external position or velocity command values, axis
Description | Specifying velocity or position command values by the SPS effective in addition to the interpolator. No monitoring takes place of transferred values for compliance with the dynamic axis limits. To activate this interface, set the parameter P-AXIS-00732 to 1.
Data type | MC_CONTROL_ADD_CMD_VALUE_UNIT, see description of Control Unit
Special features | When this interface is used, the axis positions in the interpolator and decoder are permanently offset. A repeated synchronisation of axis positions is executed, e.g. at program start, after homing, after measuring or by the NC command #CHANNEL INIT or #SET DEC LR SOLL (old syntax).

The command position value is accepted as the start value in m_add_pos_value on a rising edge at the enable input. There is no axis motion here. All further position command changes lead to an axis motion when the control unit is activated. Therefore, always specify a position command value before activating the control unit. If synchronisation should not take place (the offset remains as static offset), set the parameter P-AXIS-00322 to the value 1. In this case no start value is set on the rising edge of the enable input.

Caution:
With gantry axes, no automatic duplication of the additive command value or the master axis occurs on the slave axes. The same additive command value must be applied simultaneously to the master and slave axes in order to achieve a synchronous movement of a gantry axis configuration.

Access | PLC writes command_w + enable_w
ST path | gpAx[axis_idx]^.lr_mc_control.add_cmd_values
Commanded values
ST element | .command_w
Data type | HLI_ADD_CMD_VALUE
Activation
ST element | .enable_w

External command value, axis
Description | Transferring additional position or velocity command values. On activation both values are effective at the same time.
Data type | HLI_ADD_CMD_VALUE
ST path | gpAx[axis_idx]^.lr_mc_control.add_cmd_values.command_w
Data structure elements
ST element | .m_add_pos_value
Special features | Absolute value
Data type | DINT
Unit | 0,1 µm
Access | PLC writes
ST element | .m_add_speed_value
Data type | DINT
Unit | 1 µm/s
Access | PLC writes