Fagor CNC 8055i FL EN - Page 318

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Installation manual
CNC 8055
CNC 8055i
7.
CONCEPTS
SOFT: V02.2X
Feedback systems
Example 2:
Resolution in "mm" with sinusoidal signal encoder
We would like to obtain a 2µm resolution by using a 250-line sinusoidal encoder mounted on 5 mm-
pitch ballscrew.
We must calculate the multiplying factor "SINMAGNI" to be applied by the CNC to the pulses
provided by the encoder in order to obtain the desired resolution.
SINMAGNI = ballscrew pitch / (Nr pulses x Resolution)
SINMAGNI = 5000 µm / (250 x 2 µm) = 10
Therefore:
The feedback frequency of Fagor rotary encoders is limited to 200 KHz.
The 8055 CNC's maximum sinusoidal feedback input frequency is 50 KHz which means that
the maximum feedrate for this axis will be:
Max. Feed = 50,000 pulses/s. / 250 pulses./turn) x 5 mm/turn
Max. feedrate = 1,000 mm/s = 60 m/min.
The 8055i CNC's maximum sinusoidal feedback input frequency is 250 KHz which means that
the maximum feedrate for this axis will be:
Max. Feed = 200,000 pulses/s. / 250 pulses./turn) x 5 mm/turn
Max. feedrate = 4,000 mm/s = 240 m/min.
Example 3:
Resolution in "mm" with squarewave linear encoder
Since the CNC applies a x4 multiplying factor to squarewave signals, we must select a linear encoder
whose grading pitch is 4 times the desired resolution.
FAGOR linear encoders use a grading pitch of either 20 µm or 100 µm. Therefore, the resolution
that can be obtained with them are: 5 µm (20/4) or 25 µm (100/4).
Therefore:
The CNC's maximum squarewave feedback input frequency is 400 kHz which means that the
maximum feedrate obtainable with a 20 µm pitch linear encoder is:
Max. Feed = 20 µm/pulse x 400.000 pulses/s.
Max. feedrate = 8000 mm/s = 480 m/min.
When using Fagor linear encoders, the maximum feedrate is limited by their own characteristics to
60 m/min.
Example 4:
Resolution in "mm" with sinusoidal signal linear encoder
We have a sinusoidal linear encoder with a 20 µm pitch and we would like to obtain 1 µm resolution.
We must calculate the multiplying factor "SINMAGNI" to be applied by the CNC to the pulses
provided by the linear encoder in order to obtain the desired resolution.
SINMAGNI = linear encoder pitch / resolution = 20 µm / 1 µm = 20
Therefore:
The 8055 CNC's maximum sinusoidal feedback input frequency is 50 KHz which means that the
maximum feedrate for this axis will be:
Max. Feed = 20 µm/pulse x 50.000 pulses/s.
Max. feedrate = 1,000 mm/s = 60 m/min.
INCHES = 0 PITCH=5.0000 NPULSES = 250 SINMAGNI=10
INCHES = 0 PITCH=0.0200
PITCH=0.1000
NPULSES = 0 SINMAGNI=0
INCHES = 0 PITCH=0.0200 NPULSES = 0 SINMAGNI=20