METHOD AND APPARATUS FOR DETECTING ABSOLUTE POSITION

WIPO Patent Application WO/1988/006277

A1

A method and an apparatus for detecting an absolute position wherein the position of an object of measurement is accurately detected by interpolation between feedback pulses generated with its movement, and the command movement amount when the power source is turned on is accurately calculated the method and apparatus, consuming small power. A value stored in an absolute counter (2) which indicates an approximated absolute position of the object of measurement is updated at each feedback pulse from a feedback pulse generating circuit (1), and the updated value is retained in the counter even after the power source is turned off. As the object moves, furthermore, a counted value of interpolating pulses is temporarily stored in a correction counter (5), the interpolating pulses being generated from when the power source is on again to when a feedback pulse is generated for the first time. The absolute position of the object is calculated by a numerical controller (20) at a moment when the power source circuit is turned on depending the stored values, counted values and the moving direction designated by a movement instruction that is produced when the power source circuit is turned on. The apparatus further calculates a command movement amount based upon the absolute value that is calculated and the desired position that is instructed.

SAKAMOTO KEIJI (JP)
NAKAYAMA AKIHITO (JP)

PCT/JP1988/000177

August 25, 1988

February 19, 1988

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FANUC LTD (JP)

G01B21/00; G01D5/244; H03M1/20; H03M1/30; (IPC1-7): G01D5/245

JPS5325448A	1978-03-09
JPS4849543A	1973-07-12

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