# Index of fixed rotation axis (P-CHAN-00178)

P-CHAN-00178 | Index of fixed rotary axis to program Euler angles
Description | This parameter is only used for point-vector programming in combination with 6-axis kinematics (robots). The tool's direction vector is defined via the three vector components (e.g. "VECTOR_ABC"). These vector components result in two Euler rotation angles.

If the orientation can be defined by more than two angles (e.g. robots), the free third Euler angle must be specified by this parameter for use of vector representation.

This index results from considering the sequence of axes which define the position and manual orientation of the machine (e.g. robot).

Parameter | ori.fixed_axis_index
Data type | UNS32
Data range | 0 ... MAX(UNS32)
Dimension | ----
Default value | 0
Remarks | This parameter may only be used exclusively with P-CHAN-00436 .

Example: Kinematic structure with 3 main axes X, Y, Z and 3 rotary axes A, B, C (robot):

The rotation convention is: A about Z -> B about Y -> C about X

Axis name | index | Axis type
: A B C | : 3 4 5 | : 1. rotary axis 2. rotary axis 3rd rotary axis

According to the rotation convention above, the last axis (C) rotates about the X axis. If this axis is simultaneously the tool axis, a rotation about this axis only produces a change in the position of the manual coordinate system.

For example, if the rotation axis (C) is to be the fixed axis, the value 5 must be assigned to 'fixed_axis_index'.