FR2568029A1 - DATA TRANSMISSION INSTALLATION, IN PARTICULAR FOR DISTRIBUTION OF TIME, TRANSMITTER AND RECEIVER FOR THIS INSTALLATION - Google Patents

Abstract

1. Installation for the transmission of data from a transmitter (100) to a plurality of receivers (200) having an analog mechanism for the display of these data, in which installation the transmitter periodically sends a message representative of a pre-defined date and the receiver comprises a gear-train (R) set in movement by a motor (M), and driving a display device (A), an angular pickup (C) cooperating with an output shaft of the gear-train, a first counter (230) supplied by the angular pick-up and a second counter (220) able to determine and memorise the pre-defined date from the message received from the transmitter, a comparator (240) of the contents of the two counters, able to supply a control signal (CM) for supplying the motor when the contents (C1) of the first counter differ from the contents (C2) of the second counter and for inhibiting operation when the contents of the first counter reach the value contained in the second counter, characterised in that the motor (M) operates continuously, with the exclusion of stepping motors operating synchronously.

Description

The present invention relates to an installation

  transmission of data from a single transmitter to a plurality of receivers

the display of these data.

  One of the possible applications is the distribution of the time: in the installations of this

  type, a plurality of receiver clocks are

  together by linking to a single common clock, periodically sending

  order on a specialized line or not.

  Thus, distribution facilities are known

  the time limit applied to the clock control

  operating receivers and digital signage, is it

  to say clocks composed exclusively of circuits

  receiving coded signals from the clock-

  and, where appropriate, resetting the displayed time with respect to the periodically received coded signals. On the contrary, the invention applies to

  data transmission facilities for reception of

  Analogue mechanism, that is to say the display device is set in motion by an electromagnetic motor, usually coupled to a reduction gear train. The electromechanical movement drives a display device that can be either purely analog (dial and hands), or digital (pallet display for example); in the latter case, although the time is displayed in digital form, it is in the presence of an analog mechanism within the meaning of the invention, since only the display

  is digital, the movement being an electro-

  mechanical. Until now, to distribute the time to receivers with an analog mechanism, the most common technique consisted in equipping the receivers with a rotating permanent magnet stepping motor rotating with a polar pitch at each pulse received. of the transmitter (for example the mother clock which periodically sends a pulse), this magnet advancing the hands (or other display mode) through a

appropriate gear train.

  In this way, the hands of the clock

  receiver progressively advance at each impulse.

  It is possible to provide cumulative memory systems that allow automatic retrofitting of

  the time in case of power failure.

  Other comparable systems have also been

  proposed, using underwire movements

  polarized, oscillating coil, synchronized balance, ...

  In all cases, the difficulty lies in the design of the drive motor, which must be designed to be powered by pulses alone,

  very brief, received from the mother clock.

  On the contrary, it will be seen that the invention allows the use of a conventional continuous type motor, which can be selected from the range of micromotors to high torque motors, the choice being made only according to the size and nature of the display device to be driven. "Continuous motor" means a motor whose movement is continuous and extends as long as the power supply is maintained at its terminals, as opposed to stepper motors in all their forms (rotating magnet, with oscillating coil, .....)

  whose operation results only from the impulse

  of their diet. The "continuous-running motors" can thus comprise conventional rotary motors with direct or alternating current, whether synchronous or not. For this purpose, according to the invention:

  the transmitter periodically sends a message representing

  The mechanism of each receiver comprises: a gear train, set in motion by a continuous-running motor, and driving a display device; an angular sensor cooperating with an output shaft of the engine; gear train, * a first counter fed by the angular sensor, * a second counter, able to determine and store the predefined date from the message received from the transmitter, * a comparator of the contents of the two counters, suitable for supplying a control signal to supply the motor when the content of the first counter is different from that of the second counter, and to inhibit its operation when the content of the first counter reaches the value contained in

the second counter.

  In a first embodiment, the angular sensor is an incremental sensor able to advance the first counter by one step when the output shaft has

  rotated by a predetermined value of angular displacement.

  In a second embodiment, the angular sensor is an absolute angular encoder capable of delivering a digitized signal representative of the absolute angular position of the output shaft, this digitized signal being

  periodically loaded and stored in the first counter.

  Advantageously, an automatic counter reset circuit is provided at the time of connection of the power source of the

  each receiver clock. In the case of an incremental

  mental, this circuit also ensures the reset

of the display device.

  In the case of application to the

  time, the transmitter is a mother clock, the receivers are receiver clocks and the date is a time calendar representative of the time to be displayed, the message being issued periodically by

the master clock.

  Advantageously, the mechanism is then a self-powered mechanism powered by an internal clock, and there are provided means for substituting the control signal for the signal delivered by the internal clock after receiving and taking into account a message, in order to ensure that each message sent is reset by the time displayed on the hour

transmitted by the mother clock.

  Other features and benefits

  will appear on reading the description below,

  with reference to the attached figure, schematically showing a distribution installation of

the time according to the invention.

  This application is however in no way

  the transmission system according to the invention.

  may be used for other purposes, such as the chrono-

  recording or display of data such as departure and arrival times or other similar information. In the figure, the reference 100 designates a mother clock capable of driving a plurality

  200 receiving clocks, only one of which was

  sented. The master clock, which is of a type specially designed for the installation according to the invention, comprises a pulse generator circuit 110 supplying a circuit 120 for transmitting these pulses on a line common to all receiving clocks. This line may be a dedicated line with two conductors, or the power supply line of the clocks, the pulses being transmitted and superimposed

  at the mains frequency by a known method.

  The pulses forming the message can also be superimposed on those allowing the control of the stepper motors of the systems of the prior art; the same specialized line thus jointly conveys both types of signals, which ensures total compatibility of the system for types

different receiving clocks.

  If necessary, the master clock can be radio-controlled or radiosynchronized by a receiver device 130 of time signals transmitted by

  terrestrial or satellite broadcasting stations.

  The signal issued periodically by the clock-

  mother consists of a train of pulses representative of a predefined temporal calendar. For example, the mother clock emits every minute a train of n pulses corresponding to the number of minutes elapsed since zero hours (or from zero hours or twelve hours for a clock display: at 8 hours 14 minutes,

  thus emitted (8 X 60) + 14 = 494 pulses.

  It is also possible to envisage the transmission of a complete time signal, in binary coded form (DCB coding or other). The decoder circuit of each receiver will then determine the corresponding date

from the content of the message.

  This message is sent every minute or several times a minute when you want a

  confirmation in the meantime. Depending on the

  desired, other predetermined time calendars

  may, of course, be chosen according to the same

principle (half-minute for example).

  Preferably, this pulse train corresponds to

  to the digitized value of the selected time calendar is preceded by a reset order of the corresponding counter of the receiving clock (described below) and an order of inhibition of the operation of the motor of the same receiving clock until completion of the pulse train transmission by the master clock. In other words, these additional pulses of the message are intended to inhibit the time registration system during the time interval corresponding to the transmission of the pulse train, the latter being taken

  after completion of the signal transmission.

  Each receiver clock 200 comprises a receiver 210 and decoder circuit of the message transmitted by the mother clock, two pulse counters 220 and 230,

  a comparator 240 and a control circuit 250 of the

  M As shown above, the motor M is a continuous motor running a gear train R whose output shafts cause the

  the hands of the display device (or any other system

  analogue or digital display system).

  On an output shaft, or a cogwheel

  intermediate, there is provided an angular sensor C which delivers information representative of the actual position of the

  needles as they appear to the observer.

  This information, as a numerical value C1,

is loaded in the counter 230.

  In a first embodiment, the angular sensor is an incremental sensor capable of advancing a step counter 230 when the shaft

  of output has turned a predetermined value of

  angular cement, for example by delivering a pulse each time the needles, driven by the motor and the gear train, have advanced on the dial by one minute. This impulse increases by one step the

counter 230.

  In a second embodiment, the

  angular sensor C is an absolute angular encoder deli-

  providing a complete digitized signal representative of the position of the hands. This sensor can for example

  include a coded disc integral with the axis of the

  guille minutes and a coded disc integral with the axis of the hour hand, the signals corresponding to

  these two disks being associated to determine in -

  absolute coding the exact date of the displayed minute.

  It is also possible to provide a single coded disc integral with the hour axis, with a sufficiently fine resolution to take account of the displacements.

  of the hour hand during one minute.

  The counter 230 is then periodically loaded by the value C1 representative of the date displayed, independently of the previous content previously stored. Furthermore, the receiver circuit 210 decodes the message sent by the mother clock and loads the counter 220 with the value C2 representative of the number

pulses of the message.

  In this way, the counter 220 contains a value representative of the actual date C2, and the counter 230 represents a value representative of the date

displayed C1.

  These two values are compared in the comparator 240, which delivers a control signal CM allowing the circuit 250 to transmit the power supply (from the mains, a rechargeable battery or a dry cell) to the motor M as long as C1 remains different from C2, that is to say as long as

  the displayed time will be different from the actual time.

  When the comparator detects the equality of the two counters, that is to say when the time displayed will be reset to the real time, the control signal will inhibit the power supply of the motor M. At the next minute, the mother clock will issue

  a new message corresponding to an incremental

  (eg a new train of impulses

  one more impulse). The comparator output will then change level and the M motor will again

  actuated, driving the needles and the angular

  until the latter comes to increase the

  230 meter contents of a unit.

  An electromagnetic stop brake, of a type known per se, is provided so as to immobilize the needles exactly at the position

  desired, without exceeding due to the mechanical inertia

the device.

  The installation also has, preferably,

  the following characteristics: At the beginning of the message, there is provided a reset command RZ2 of the counter 220, as well as an inhibition command I of the motor supply during the time interval corresponding to the transmission of the message. This prevents the engine from being switched on as long as the value of the meter is not exceeded.

  has not stabilized at its final value.

  There is provided an additional circuit 260 for resetting both counters (as well as the mechanism, in the case of an incremental encoder) at the time of connection of the power supply. This device avoids any erratic operation of the system before

  reception of the first message following the connection.

  In the case where the angular sensor is an incremental sensor, it is necessary, in addition to resetting the counter 230, to set the hands to the position corresponding to this zero value (zero hours or twelve hours). This setting of the needles can be done automatically by the mechanism of the receiving clock at the time of connection or the

cut off the power supply.

  In addition, it is not necessary that the message be issued periodically, or whenever the date progresses by one unit. In particular: 25. in the case of the distribution of the hour, the system

  according to the invention may be only a subsystem

  used only for the registration (periodical or on order) of the clocks. The latter are then provided with an autonomous internal clock 280 (or simply synchronized to the sector) and a switching circuit 270 allowing, at the time of sending the reset message, to neutralize it and to replace it the decoded information received from the mother clock. In the case of timing, it may be considered to temporarily suspend the transmission to allow the display of an intermediate time during

  a fixed term. When resuming the trans-

  mission, the needle will "catch up" until

display the real time again.

  In the case of remote display of information (eg departure and arrival times of trains), the message need only be issued when there is

  changing the values to display.

  Many variants of embodiment

  can be considered. The circuit of the clock receiving

  trice, described in wired logic, can also be implemented in the form of microprogrammed logic realizing

  the same function, ie intermittent feeding

  of a continuous-running engine with variation of

  cyclic on / off ratio, to enable the rat-

  page of time and the registration on the true time transmitted

by the mother clock.

Claims (10)

  1. A data transmission facility from a transmitter <(100) to a plurality of analog mechanism receivers (200) for displaying such data, characterized in that: 5. the transmitter periodically sends a Representative message of a predefined date, the mechanism of each receiver comprises: * a gear train (R), set in motion by a motor (M) continuous operation, and driving a device (A) display, * an angular sensor (C) cooperating with an output shaft of the gear train, * a first counter (230) fed by the angular sensor, * a second counter (220), able to determine and store the predefined date from the message received from the transmitter, * a comparator (240) of the contents of the two counters, able to deliver a control signal (CM) for supplying the motor when the content (C1) of the first counter is different from that (C2) of the second counter, and to inhibit its function when the content of the first counter reaches the   value contained in the second counter.   2. An installation according to claim 1, characterized in that the sensor (C) is an incremental sensor capable of advancing the first counter by a step when the output shaft has rotated by one value.   predetermined angular displacement.   3. An installation according to claim 1, characterized in that the angular sensor (C) is an absolute angular encoder capable of delivering a digitized signal representative of the absolute angular position.   of the output shaft, this digitized signal being   loaded and stored in the first counter.   4. An installation according to claim 1, characterized in that there is further provided a circuit (260) for automatically resetting the counters at the time of connection of the power supply source. mechanism of each receiver.   5. An installation according to the claims   2 and 4 in combination, characterized in that the reset circuit also ensures the reset of the display device.   6. An installation according to claim 3, characterized in that the message sent by the transmitter is preceded by a reset order of the second counter, and an order of inhibition of the operation of the engine.   until the message is completed.   7. An installation according to claim 1 applied to the distribution of the time, characterized in that the transmitter is a mother clock, the receivers are receiving clocks and the date is a time calendar representative of the time to be displayed ,   the message being issued periodically by the mother clock.   8. A receiver clock for an installation   The arrangement according to claim 7, characterized in that the mechanism is a self-operating mechanism powered by an internal clock (280), and in that means (270) are provided for substituting the control signal for the signal delivered by the internal clock after reception and taking into account of a message, so as to ensure at each sending of the message the registration of the time   displayed on the time transmitted by the mother clock.   9. Transmitter for an installation according to one of claims 1 to 7.   10. Receiver for installation according to one of claims 1 to 7.