Typewriting machines – Miscellaneous
Reexamination Certificate
1998-12-15
2001-04-03
Hilten, John S. (Department: 2854)
Typewriting machines
Miscellaneous
C347S019000
Reexamination Certificate
active
06210056
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a circuit arrangement for level conversion of binary signals in a control system for a printing-technology machine, in particular, a printing press. In order to control operating procedures of a machine in the field of printing technology, a multiplicity of actuators and sensors are provided which interact with one or more control circuits. If binary signals are transmitted line-bound between the actuators or sensors and a control circuit, then the binary signals are expressed by DC voltage values which are generated by electronic components of a driver circuit. On account of the unavoidable component tolerances and a desired interference immunity, a low level or L level and a high level or H level are defined as the binary signal values (0; 1), the H level lying in a range above an upper threshold value and the L level lying in a range below a lower threshold value. The range between upper and lower threshold values corresponds to no binary signal value (0; 1). Driver circuits and receiver circuits operate either according to the principle of so-called positive logic, in which case the binary signal value (1) is defined by the H level, or according to the principle of negative logic, in which case the binary signal value (1) is defined by the L level. In order to ensure the interaction of the actuators or sensors with the control circuit, the binary signal values (0; 1) must correspond to the desired levels. In order to increase the flexibility in the controllers and the connected actuators or sensors, it has been known heretofore to provide additionally inverted inputs and outputs, respectively, for inputs and outputs, with the result that it is optionally possible to operate in positive or negative logic. Faulty circuits cannot be precluded in this case, in particular when an element is to be renewed on the control circuit side or on the actuator/sensor side. In order to reduce the probability of faulty circuits, it is possible to resort to compatible elements of one and the same property, which have to be available in stock and should, as much as possible, originate from the same manufacturer. At the output, driver circuits have an electrical switching element which, when it is driven, generates an H or L level at the output. In this regard, embodiments are possible wherein the switching element establishes a low-impedance connection to a positive operating voltage source or to the zero potential of the operating voltage source. In further different embodiments, the switching elements are connected to resistors. In the case of push-pull output stages, two electrical switching elements act at the output, the switching elements being able to connect the output in a low-impedance manner both with respect to the positive operating voltage source and with respect to the zero potential or a negative operating voltage source. In addition to the switching elements described hereinbefore, which, at the output, set DC voltage values corresponding to the binary signal values (0; 1), driver circuits are known which have switchable current sources in addition to the output stage.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a circuit arrangement for level conversion of binary signals for a control system for printing-technology machines wherein the compatibility of a control circuit thereof and of actuators or sensors of the machine connected thereto is improved.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a circuit arrangement for the level conversion of binary signals in a control system of a printing-technology machine, comprising a component for transmitting a signal and a component for receiving the signal, the signal-transmitting component having an element for generating a binary level value, and a window discriminator provided between the signal-transmitting component and the signal-receiving component, the window discriminator having a lower threshold value and an upper threshold value corresponding to binary level values, the window discriminator further having a signal input and a signal output, the signal input being connected to an output of the signal-transmitting component, the signal output of the window discriminator being connected to an input of the signal-receiving component, the signal input being at a level lying between the lower and the upper threshold values when the element of the signal-transmitting component, for generating a binary level value, is not driven.
In accordance with another feature of the invention, the binary level lying between the threshold values corresponds to an average value of the upper and the lower threshold values.
In accordance with a further feature of the invention, the signal input is additionally connected to a tap of a voltage divider, the voltage divider being connected to voltage sources having levels which are below the lower threshold value and above the upper threshold value.
In accordance with a concomitant feature of the invention, the voltage divider is formed of two series-connected resistors.
Irrespective of whether the driver output stage of a component transmitting a binary signal is formed as a voltage source or as a voltage source with an additional current source, or operates according to the principle of positive or negative logic, a binary signal
0
or
1
is always generated when an activated driver output stage is at the output of the circuit arrangement, the binary signal serving to characterize the state of activation of the driver output stage in accordance with the agreed definition.
It is expedient to integrate the circuit arrangement in the actuators or sensors. The actuators and sensors, respectively, are thereby enabled to operate on any desired controls. The level conversion proceeds virtually with no time delay. The components which are used are commercially available, reliable and cost-effective. The configuration of the signal-outputting components of a control system of a printing-technology machine is simplified because, in order to generate a binary control signal
0
or
1
, the outputting components merely have to be brought into an activated state.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a circuit arrangement for level conversion of binary signals in a control system of a printing-technology machine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein:
REFERENCES:
patent: 4083042 (1978-04-01), Kushin et al.
patent: 4847865 (1989-07-01), Larson
patent: 4865075 (1989-09-01), Smith
patent: 5041795 (1991-08-01), Bowers
patent: 5359238 (1994-10-01), Lesko
patent: 5533054 (1996-07-01), DeAndrea et al.
patent: 5757394 (1998-05-01), Gibson et al.
Chau Minh H.
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Hilten John S.
Lerner Herbert L.
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