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Installation manual
CNC 8055
CNC 8055i
7.
CONCEPTS
SOFT: V02.2X
Gear ratio management on axes and spindle
With linear encoder:
•PP115 (drive) = bit 0 = 1 (direct external linear feedback).
•NP117 (drive) = glass/tape graduation pitch of the linear encoder = 20.
•NP118 (drive) = actual (real) counting pitch of the linear encoder = 4. If there is no multiplier
circuit (EXE) incorporated into the feedback, the value is the same as NP117.
•NP165 (drive) = 1001 (see table of the drive manual).
•NP166 (drive) = 1000 (see table of the drive manual).
2. External feedback connected to the CNC
Axis parameter DRIBUSLE (P63) = 0.
Parameters involved in the calculation of the velocity command:
Axis parameter G00FEED (P38) = Maximum feedrate of the axis = 20000.
Axis parameter PITCHB (P86) = Leadscrew pitch = 20.
Motor gear ratio:
axis parameter INPREV (P87) = Input revolutions =3.
axis parameter OUTPREV (P88) = Output revolutions = 1.
NP121 (drive) = it automatically loads the value of axis parameter INPREV (P87) of the CNC.
NP122 (drive) = it automatically loads the value of axis parameter OUTPREV (P88) of the
CNC.
NP123 (drive) = it automatically loads the value of axis parameter PITCHB (P86) of the CNC.
Parameters involved in the calculation of the position feedback.
With rotary encoder:
•axis parameter NPULSES (P8) = number of pulses per turn of the encoder = 18000.
•axis parameter SINMAGNI (P10) = Multiplying factor if the encoder is sinusoidal = 200.
•axis parameter EXTMULT (P57) = Multiplying factor of the feedback = 1.
•Axis parameter PITCHB (P86) = Leadscrew pitch = 20.
With linear encoder:
•axis parameter PITCH (P7) = linear encoder pitch = 20.
•axis parameter NPULSES (P8) = 0.
•axis parameter SINMAGNI (P10) = Multiplying factor if the encoder is sinusoidal = 0.
•Axis parameter EXTMULT (P57) = Multiplying factor of the feedback = 20/4 = 5.
Calculation of the velocity command for a feedrate of G00FEED:
Command = (G00FEED x INPREV) / (PITCHB x OUTPREV) = (20000 x 3) / (20 x 1) = 3000 rpm.
Calculation of the resulting resolution:
TTL encoder: Resolution = PITCHB / (4 x NPULSES)
Sinusoidal encoder: Resolution = PITCHB / (SINMAGNI x NPULSES)
TTL linear encoder: Resolution = PITCH / 4
Sinusoidal linear encoder:Resolution = PITCH / SINMAGNI
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