Reading Or Setting The Field Angle Via The Plc - HEIDENHAIN iTNC 530 HSCI Technical Manual

7.9.4 Reading or setting the field angle via the PLC

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For axes without encoders with Z1 tracks, which cannot be moved when
switched off (e.g. due to Hirth coupling), or if it has been ensured that they
cannot moved when switched off, Module 9149 can be used to read out the
field angle after positioning. This axis-specific field angle must be stored via
the PLC in non-volatile memory.
It is also important that the saved field angle is cleared (set to 0) before each
positioning, so that the axis (motor) is not started with an incorrect field angle
after a power failure. This way an incorrect writing of the field angle is
prevented if a power failure occurs.
The nonvolatile field angle must be set via Module 9149 before the drives of
the affected axis are switched on. This means that it is not necessary to
determine the field angle again.
Danger
Please note the following items when setting/reading the field angle via the
PLC:
An incorrectly set field angle can lead to undesirable reactions of the

motor, including uncontrollability. It might even move in the wrong
direction!
If the axis position is moved again after the field angle has been read,

then the determined field angle may no longer be used.
The commutation angle may be set only after you have ensured that the

stored commutation angle corresponds to the current position (e.g. due
to Hirth coupling).
The module is suitable only for synchronous, torque, or linear motors in

conjunction with nonaligned encoders without EnDat interface.
The module responds with a value only if the reference mark has been

traversed.
The commutation angle for an axis can be set only once after the control

is switched on and before the drives are first switched on.
HEIDENHAIN Technical Manual iTNC 530 HSCI