Tilting solution

Application

A defined spatial angle can be reached by performing various rotary axes movements.

In order to achieve a certain solution, for example to avoid collisions, you can pre-position the rotary axes or program SYM (SEQ).

Difference between spatial angles and axis angles

Description of function

In the optional machine parameter prohibitSEQ (no. 201209), the machine manufacturer defines whether the control will provide the SEQ option in addition to SYM.

 
Tip

HEIDENHAIN recommends using SYM because this function is suitable for all machine kinematics.

Please note that you must not simply replace SEQ with SYM, because the behavior is different depending on the machine kinematics.

Option­

Meaning

SYM

With SYM, you select a tilting solution relative to the symmetry point of the primary rotary axis.

The symmetry point lies at the center of the rotary axis.

The primary rotary axis is the first rotary axis, seen from the tool, or the last rotary axis, seen from the table.

Tilting solution SYM

SEQ

With SEQ, you select a tilting solution relative to the basic position of the primary rotary axis.

Using SEQ only makes sense for machine kinematics where the symmetry point of the primary rotary axis lies at 0°.

Tilting solution SEQ

Reference point for SYM: A = –90°

Reference point for SEQ: A = 0°

Entering SYM or SEQ is optional.

If you do not define SYM (SEQ), the control will select the solution variant with the smallest number of rotary axis movements, based on the current rotary axis positions.

If no tilting solution is available within the traverse range of the machine, the control will issue the Entered angle not permitted error message. This happens regardless of whether you have defined SYM (SEQ) or not.

Tilting solution SYM

Using the SYM function, you select a solution option relative to the symmetry point of the primary rotary axis:

  • SYM+ positions the axis in the positive half-space
  • SYM- positions the axis in the negative half-space

As opposed to SEQ, SYM uses the symmetry point of the primary rotary axis as the reference point. Every rotary axis has two symmetry positions, which are spaced by 180°. In some cases, only one symmetry position is within the traverse range of the machine.

 
Tip

Determine the symmetry point as follows:

  1. Perform PLANE SPATIAL with any spatial angle and SYM+
  2. Save the axis angle of the primary rotary axis in a Q parameter (e.g., –80)
  3. Repeat the PLANE SPATIAL function with SYM-
  4. Save the axis angle of the master axis in a Q parameter (e.g., –100)
  5. Calculate the average value (e.g., –90)
  6. The average value corresponds to the symmetry point.

Tilting solution SEQ

Using the SEQ function, you select one of the solution options relative to the basic position of the primary rotary axis:

  • SEQ+ positions the axis in the positive tilting area
  • SEQ- positions the axis in the negative tilting area

SEQ is based on the basic position 0° of the primary rotary axis. If both solution options are within the positive or negative area, the control will use the tilting solution that requires the smallest number of rotary axis movements, relative to the current position. If you need the second-best solution, then either pre-position the rotary axes (in the area of the second solution) before tilting the working plane, or use SYM.

Examples

Machine with C rotary axis and A tilting table.
Programmed function: PLANE SPATIAL SPA+0 SPB+45 SPC+0

Limit switch

Start position

SYM = SEQ

Resulting axis position

None

A+0, C+0

Not prog.

A+45, C+90

None

A+0, C+0

+

A+45, C+90

None

A+0, C+0

A–45, C–90

None

A+0, C–105

Not prog.

A–45, C–90

None

A+0, C–105

+

A+45, C+90

None

A+0, C–105

A–45, C–90

–90 < A < +10

A+0, C+0

Not prog.

A–45, C–90

–90 < A < +10

A+0, C+0

+

Error message

–90 < A < +10

A+0, C+0

A–45, C–90

Machine with B rotary axis and A tilting table (limit switches: A +180 and –100). Programmed function: PLANE SPATIAL SPA-45 SPB+0 SPC+0

SYM

SEQ

Resulting axis position

Kinematics view

+

A–45, B+0

-

Error message

No solution in limited range

+

Error message

No solution in limited range

-

A–45, B+0

 
Tip

The position of the symmetry point is contingent on the kinematics. If you change the kinematics (such as changing the head), then the position of the symmetry point changes as well.

Depending on the kinematics, the positive direction of rotation of SYM may not correspond to the positive direction of rotation of SEQ. Therefore, ascertain the position of the symmetry point and the direction of rotation of SYM on each machine before programming.