HEIDENHAIN MANUALPLUS 620 - Page 651

January 2012 6.4 Encoders 651
The controller unit assumes that the motor encoder has only one line per
revolution. Set the following:
 MP_posEncoderDist:: For each axis, enter the traverse distance per motor
revolution.
 MP_posEncoderIncr:: Enter the value "1".
 MP_distPerMotorTurn: For each axis, enter the traverse distance per
motor revolution.
 CfgServoMotor - MP_motStr (401313): Enter the value "1" for the line
count of the motor encoder.
Examples:
 ERN 1387 – Only motor encoder (no linear encoder):
Incremental rotary encoder for servo drives. 2048 lines per 360°. The axis
moves 10 mm per motor revolution.
MP_posEncoderDist = 10
MP_posEncoderIncr = 2048
MP_distPerMotorTurn = 10
MP_posEncoderType = CC_MOTOR_ENCODER
 RON 785C on rotary table with direct drive:
Incremental angle encoder with integral bearing and distance-coded
reference marks. 18 000 lines per 360°. 36 reference marks. Nominal
increment between reference marks is 20°.
MP_posEncoderDist = 360
MP_posEncoderIncr = 18000
MP_distPerMotorTurn = 360
MP_posEncoderRefDist = =1000 [signal periods]
MP_posEncoderType = CC_DISTANCE_CODED
 RCN 729 with gear transmission on rotary table:
Absolute angle encoder with EnDat 2.1 interface and integral bearing. 32
768 lines per 360°. Gear transmission ratio: 17:1
MP_posEncoderDist = 360
MP_posEncoderIncr = 32768
MP_distPerMotorTurn = = 21.17647059
MP_posEncoderType = CC_EXTERN_ENDAT
Note
HEIDENHAIN recommends:
The optimum manufacturing precision can only be attained with linear
encoders. A control without linear encoders finds the axis position through
the pitch of the ball screw. The problem is, the ball screw gets hot during
machining and expands. And the result is a position measurement that
deviates from the actual position, causing error. With linear encoders, the
control always determines the correct slide position. This means that your
machine positions its axes with constantly high precision.
More information is available on the Internet at:
http://www.heidenhain-shows-the-way.com
20
360
18000
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÷
360
17
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