# Axis identification

Axis name (PCS)
Description | Name of the logical axis used for the current reference in the current automatic program / manual block (e.g. X, Y, Z). This may be changed by default when the channel (SDA-MDS list) is programmed or dynamically in the NC program by means of a swap command.
Signal flow | CNC → PLC
ST path | gpCh[channel_idx]^.bahn_state.coord_r[axis_idx].axis_name_r.zeichen(HLI_ACHS_NAME_LAENGE)
Data type | STRING(HLI_ACHS_NAME_LAENGE)
Access | PLC reads

Axis number (PCS)
Description | Logical axis number which is unique system-wide for the axis which is currently traversed on the channel. The logical axis number is defined arbitrarily in the axis parameter list and is required to identify the axis in case of an axis swap, among other things (e.g. #CALL AX [X, 1, 1, 0]).
Signal flow | CNC → PLC
ST path | gpCh[channel_idx]^.bahn_state.coord_r[axis_idx].log_achs_nr_r gpAx[axis_idx]^.ipo_state.log_achs_nr_r
Data type | UINT
Value range | [1, MAX_UNS16] In TwinCAT normally [1, gNrAX]
Access | PLC reads

Axis spindle (ACS)
Description | Indicates whether the axis is currently interpolated by the path interpolator (e.g. thread drilling, tapping) or the BF spindle.
Signal flow | CNC → PLC
ST path | gpAx[axis_idx]^.ipo_state.spindle_axis_r
Data type | BOOL
Value range | [TRUE = the axis is traversed by the BF spindle, FALSE]
Access | PLC reads

Axis type (PCS)
Description | Type of axis
Signal flow | CNC → PLC
ST path | gpCh[channel_idx]^.bahn_state.coord_r[axis_idx].axis_type_r gpAx[axis_idx]^.ipo_state.type_r
Data type | UINT
Value range | 1 = Translator, 2 = Rotator, 4 = Spindel
Access | PLC reads

Channel number of the axis
Description | Number of the channel by which the axis is currently commanded. == 0: Axis is currently not on a channel or spindle is not processing any channel command. != 0: Axis belongs to a channel or spindle is executing a channel command.
Signal flow | CNC → PLC
ST path | gpAx[axis_idx]^.lr_state.cnc_channel_r gpAx[axis_idx]^.ipo_state.cnc_channel_r
Data type | UINT
Value range | [1, HLI_SYS_CHNMAX]
Access | PLC reads