US 4,755,070 AGranted

Circuit for actuating electric motors, especially in an electronic typewriter

AssigneeIng. C. Olivetti & C., S.p.A.

InventorWalter Cerutti

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Abstract

In an electronic typewriter having a printing device of the daisywheel type, the direct current electric motors which control the rotation of the character-carrying element, the movement of the carriage along the various printing positions and the rotation of the platen roller for line spacing are associated with corresponding transducers which detect the angular position thereof, and are actuated by a single integrated circuit connected to a microprocessor by an address and data bus (43). The microprocessor determines, for each of the motors, the angular amplitude of the rotary movement and the time required to cover each of the elementary angular distances, in accordance with a given speed law and addresses with data, including the said time, a plurality of circuit modules (B1, B2, B3) individual to the motors. The modules issue motor command signals (e.g. M11, M21, M31). Checking as between the actual speed and the desired or theoretical speed is effected by the modules of the integrated circuit using the timing signals (e.g. STA 1, STB 1) generated by the transducers connected to the motors. The modules send back interrupt signals (INT 1, INT 2, INT 3) which provide interrupt vectors (46) for the microprocessor, enabling the microprocessor to determine the new data to be sent to the modules.

Claims14

Dependent claims

A circuit for actuating at least an electric motor of an electronic typewriter, wherein the typewriter comprises an electric motor having a shaft performing elementary rotary movements;

transducer means associated with said motor for generating position signals of impulse type which are indicative of each elementary rotary movement effected by said shaft;
a microprocessor for determining a number of said elementary rotary movements to be effected by said shaft in order to attain a given angular displacement;
and a circuit module connected with said microprocessor and with said motor and responsive to each of said position signals for controlling the velocity of said shaft for elementary rotary movement of said shaft;
wherein said microprocessor also comprises microprocessor time memory means permanently storing a plurality of values of theoretical times TR associated with said number of said elementary movements and read-out means actuatable for reading-out in said circuit module one of said theoretical times, wherein said plurality of values of said theoretical times TR being provided for performing said number of said elementary rotary movements according to a predetermined law of movement of said shaft along with said given angular displacement;
and the combination comprising:
said circuit module comprises a circuit module memory means for storing a theoretical time signal TT associated with a value of said plurality of values of theoretical times TR read-out from said microprocessor time memory means;
timing means responsive to said position signals for determining an evolving time signal CNT indicative of the interval of time elasping from a last received position signal along one elementary rotary movement;
comparison menas for comparing said evolving time signal CNT with said theoretical time signal TR and generating an equality signal REF when the evolving time signal CNT is equal with the theoretical time signal TR;
logic means responsive to the position signal and to the equality signal REF for actuating said motor to correct the velocity of said shaft during said one elementary rotary movement;
means for generating a corresponding interrupt signal for the microprocessor, at the end of said one elementary rotary movement;
and
data addressing means for receiving data processed by said microprocessor in said circuit module, wherein the read-out means of said microprocessor respond to said interrupt signal to generate a new value of said plurality of values of theoretical times TR for another elementary rotary movement following said one elementary rotary movement;
and
wherein said logic means accelerates said motor during said one elementary movement independently of any command by said microprocessor if the equality signal REF has been received before said position signal as indicative of the end of said one elementary movement.

11 more elements

An electronic circuit for actuating a plurality of electric motors of an office typewriter comprising a microprocessor which is capable of determining for each of the motors the direction of rotation and the angular amplitude required to attain a given angular position and calculating for each rotary movement a number of elementary rotary movements to be effected in order to attain said given angular position and, for each elementary rotary movement, a theoretical time signal TR for performing said elementary rotary movement;

a plurality of transducers associated with said motors for generating on a plurality of lines position signals which are indicative of the angular position attained by said motors;
and a plurality of circuit modules, wherein each circuit module comprises circuit module memory means for storing the value of said theoretical time signal TR;
timing means connected with one line of said plurality of lines and responsive to said position signals for determining an evolving time signal CNT indicative of the interval of time elapsing from the time of receipt of a last position signal along said elementary rotary movement;
comparison means for comparing the evolving time signal CNT with the theoretical time signal TR;
output means controlled by said comparison means and operative on one of said plurality of electric motors, wherein said comparison means causes said output means to accelerate said one motor independently of any command by the microprocessor if a position signal has not been received in said one line of said plurality of lines before the theoretical time TR;
and means for generating a corresponding interrupt signal associated with said position signal received on said one line of said plurality of lines for causing said microprocessor to read-out on said circuit module said theoretical time signal TR and a control signal for controlling the acceleration and deceleration of said motor.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/795,165Filed 5 Nov 1985
Priority: IT 68096 A/845 Nov 1984
Granted: 5 Jul 1988
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G05B 19/4142
Structure of the control system, e.g. common controller or multiprocessor systems, interface to servo, programmable interface controller:…
B41J 29/38
Details of, or accessories for, typewriters or selective printing mechanisms not otherwise provided for: drives, motors, controls or automatic…
G05B 19/23
Using an incremental digital measuring device: for point-to-point control
G05B 2219/45187
Nc applications: printer