Instrument reference system
AssigneeAustralian Arrow Pty Ltd
InventorDavid McIntyre Fyfe
Life of this patent
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Abstract
A method and system for calibrating a motor-driven instrument pointer (8) against a stop (5) without using feedback includes, in a first power state, driving the pointer (8) at full torque against the stop (5), then driving the pointer (8) against the stop at a reduced torque for a predetermined radial distance so at the pointer (8) is caused to be held against the stop (5). A third driving step, at reduced torque for a further predetermined radial distance, may be used in a second power state to move the pointer (8) against the stop (5).
Claims20
A method of calibrating an electronically controlled, electric motor driven instrument, comprising the steps of:
- (a) connecting electrical power to the instrument,
- (b) driving the motor at full torque for a first predetermined radial distance whereby the motor or a pointer driven thereby contacts a stop,
- (c) driving the motor at a reduced torque for a second predetermined radial distance whereby the motor or pointer is caused to be held against the stop.
A method according to any one of the preceding claims, wherein the second predetermined radial distance is between 1° and 90°.
A system for calibrating an instrument or equipment operated by an electric motor, such as a stepper motor, comprising:
- a pointer means engageable with said electric motor and adapted to be driven thereby,
- a stop means positioned at a desired reference point wherein,
- in a first powered state, the motor is accelerated at a maximum torque for a first predetermined radial distance to move said pointer towards a position whereat said stop is engaged,
- thereafter, said motor is re-accelerated at a reduced torque for a second predetermined radial distance whereby the pointer is caused to be moved and held against said stop.
Dependencies are inferred from the claim text.