July 2013 6.12 Spindle 945
6.12.1 Position encoder of the spindle
Analog and digital spindles can be driven in a closed control loop. In this case
the spindle needs its own position encoder:
Define the position encoder input in MP111.x.
• If you have a digital spindle and would like to use the speed encoder also
as a position encoder, then you must set MP111.x = 0.
Enter in MP3142 the line count of the encoder to be used. 1 V
PP
signals
undergo 1024-fold subdivision
Enter in MP3142 how the position encoder is mounted on the spindle. Due
to the higher required accuracy, the position encoder must be mounted
directly on the spindle: MP3143 = 0
If design considerations make this impossible:
Define the encoder-to-spindle transmission ratio in MP3450.x and
MP3451.x for each gear stage.
In this case there will be several reference pulses per revolution. For example,
with a transmission of 4:1 (motor to spindle), you will receive four reference
pulses (every 90°) per spindle revolution.
Evaluate the reference mark with Module 9220. “Renewed traversing of the
reference marks" on page 804.
If MP3143 = 1, then X9 pin 14b is evaluated as the reference signal. If MP3143
= 3, then the second signal at X9 pin 14b is evaluated as the reference signal.
This can be necessary if the spindle is located shortly before the switch for the
reference signal. This might not be detected, and so only the next signal can
be evaluated. If MP3143 = 3, the spindle performs two revolutions, and
therefore the second signal at X9 pin 14b is used as the reference signal.
In both cases the reference mark of the position and speed encoder is not
evaluated.In this case the reference signal is generated externally and must
be evaluated with Module 9220, see "Renewed traversing of the reference
marks" on page 804.
During referencing of the spindle (with PLC Module 9220, special sequence
with external sensor X9 pin 14b), as of software version 606 42x-02 the
specified spindle braking ramp is used for braking when the reference mark or
the external switch is reached. Up to now the spindle used to be stopped on
the emergency stop ramp. The ramp gradient of the spindle with M03 and
M04 for gear ranges 1 to 8 is defined in MP3411.0-7.
Due to its low accuracy, this solution is not recommended.
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