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Failure Indicator for Stepper Circuitry

IP.com Disclosure Number: IPCOM000084603D
Original Publication Date: 1975-Dec-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Beavers, JA: AUTHOR

Abstract

There is shown a useful test system for evaluating the operational condition of a two-phase, four-winding stepper motor and driver configuration. The test circuitry monitors the machine power supply voltages and logic levels. In addition, the two-phase resistors can be checked and tests can be made on the stepper motor drivers of the open-loop system, as well as the stepper motor itself. Included in the circuitry design is a rotary switch which significantly improves the versatility and reliability of the circuit.

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Failure Indicator for Stepper Circuitry

There is shown a useful test system for evaluating the operational condition of a two-phase, four-winding stepper motor and driver configuration. The test circuitry monitors the machine power supply voltages and logic levels. In addition, the two-phase resistors can be checked and tests can be made on the stepper motor drivers of the open-loop system, as well as the stepper motor itself.

Included in the circuitry design is a rotary switch which significantly improves the versatility and reliability of the circuit.

In using the tester, the stepper motor drivers A, A, B and B are disconnected from the motor and the tester inserted in the same connectors. Each stepper motor driver output is tested at separate positions of the rotary switch S. The drivers not being tested are effectively shorted to ground through the common wiper of the switch S.

Previous designs were susceptible to the shunting effects of the commutating capacitors C(c). For example, a voltage transition at driver A would also give a voltage transition at A, giving a potentially false indication of an operating driver at A. In the present circuit, only the switching driver is gated to the single-shot SS which in turn gates light-emitting diode (LED) 1. All other functions are gated out.

The stepper motor coil test is performed by utilizing the concept of approximately equal coil resistances of the stepper motor.

V1 and V2 are voltage drops across the coils and...