JPS581438B2 - 7 segment - Google Patents

Abstract

1473828 Lamp failure alarms DRESSER EUROPE SA 3 May 1974 [3 May 1973] 21139/73 Heading G4N In a seven-segment display device of the type having a common anode 2 and a cathode 3 for each segment with a cathode driver 4 connected to each cathode, or vice versa, a respective circuit connection 6 including a series diode 7 is connected to each cathode (or anode) and a detector 8 is connected to each connection so as to draw current through the respective diode from the respective cathode driver (or anode driver) in the event of a segment failure, the output from the detector being arranged to give a warning indication. This indication may be given by a visible and/or audible warning device 10 and/or by causing all the cathodes to be energized. In the arrangement described with reference to Fig. 2 (not shown), thirteen display devices are provided respective cathodes being connected in common to the cathode drivers and to the circuit connections 6. This arrangement is activated in a time-division multiplex manner. The display device arrangement may be provided on the dispensing nozzle of a fuel pump as described with reference to Figs. 3 and 4 (not shown).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seven segment electronic display, and more particularly to an apparatus for detecting failures in a seven segment display.

The present invention further relates to a liquid fuel dispensing pump using a seven segment electronic display.

A seven segment display device can be a solid state device having seven segments, each segment having an anode and emitting light when a current is passed between the anode and the cathode.

For convenience, the anodes or cathodes of all segments are connected to a common terminal, and selective light emission of each segment can be achieved by selectively applying a cathode voltage to each cathode or applying an anode voltage to each anode, depending on the case. It is carried out by

Hereinafter, explanations will be made with reference to devices that have a common anode, but
The present invention is equally applicable to devices in which the cathode is common;
It should be understood that references to "anode" and "cathode" may be interchanged as appropriate.

It may not be immediately apparent to a supervisor when one or more of the segments of a seven segment device fails.

That's because the device simply gives an incorrect numerical output.

For some applications, particularly retail labeling, it is important, and as much as possible legally required, that false labeling should not go undetected.

SUMMARY OF THE INVENTION The present invention provides a device for detecting failures in seven segment devices.

According to the present invention a seven segment display having a common anode and cathode for each segment, a cathode drive connected to each cathode for supplying cathode current to the appropriate segment when activated, and a cathode drive connected to each cathode. circuit connections containing series diodes, a detection circuit connected to the circuit connections to draw current through each diode from each cathode driver in the event of a device segment failure, and an alarm when current is received through the diodes. A seven segment display is provided that includes an output from a connected detection circuit for providing an indication.

The output from the detection circuit may simply be connected to a visual and/or audible alarm device.

However, alternatively or preferably in addition, the output is connected to activate the all-cathode drive when sensing the current through the diode.

In this way the indication given by the device is kept as a fixed number which should be "8" for the faulty segment.

A preferred embodiment of the invention includes a plurality of seven segment devices, each cathode commonly connected to a cathode drive and circuit connections.

With this device, activation of all cathode drives provides an "8" index on all devices except for the failed device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device for operating a seven segment multiple numeric display in a time division multiplexed manner.

For this purpose, each display device has a respective anode drive, which are activated in sequence and periodically.

Therefore, only one device is activated at a time.

A set of common cathode drivers is provided, each connected to each cathode of the display.

The pattern of potentials applied by the common cathode drive is varied sequentially in synchronization with the cycles of the anode drive, so that when each set of common cathodes of the device is energized, the cathodes of that device are energized. , the cathode of the device is energized to give the appropriate numerical display.

Furthermore, the cathode pattern can be established by the output from a binary register/decoder being set for each digit by a series of binary pulses.

In this way the entire display device can be remotely controlled with only four control wires.

One additional wire is required for the alarm signal from the fault detection device.

The invention is particularly useful in providing signs for liquid fuel dispensing pumps, for example in gas stations.

According to the invention, therefore, it is provided to indicate fuel sales information such as fuel capacity, fuel cost and/or fuel unit price by means of a series of seven segment devices having a segment failure device as described above.

The display for each fuel pump may be located in the pump body, but is preferably also dually visible in the central control unit where the cashier is located to receive the disbursements.

The time-sharing multiplexing device described above connects the time-sharing (
It is particularly useful for conveying information to be displayed in a time-sharing manner.

The present invention also contemplates an improved display device for a liquid fuel distribution pump.

According to another aspect of the invention, a display device for displaying sales information on a liquid fuel dispensing pump includes a series of seven segment electronic displays including one segment for each digit of the information to be displayed. One device is provided, and a series of devices is mounted on the handle of the fuel pump nozzle.

With this device, the display can be easily observed by the operator when dispensing.

The display can be duplicated in the pump body and/or in the central control unit by the same series of seven segment devices.

Due to the importance of safety, the display on the nozzle handle:
Preferably, the entire display is enclosed within a block having at least a transparent surface so that the display can be viewed.

The display is preferably controlled in a time division multiplexed manner by four wires in the manner described above.

Preferably, the segment failure detection device is provided as described above.

The present invention will be explained below with reference to the drawings.

In FIG. 1 there is shown an arrangement of a display device comprising a seven segment display device 1 whose segments have a common anode 2. In FIG.

The segment has a respective cathode 3 driven by a respective cathode drive in a drive unit 4.

The drive unit 4 receives input signals at four input terminals 5 which determine the output voltage pattern applied to the cathode 3, including a decoder.

The illuminated segment and therefore the displayed numerical value is determined by the input at terminal 5.

Each cathode is connected to a respective circuit connection as shown at 6, each circuit connection including a series diode as shown at 7.

The diode is connected to the input of the detection circuit 8.

If one segment of the device 1 fails, this means that when a cathode voltage is applied to each cathode 3, no current is drawn through the device via that cathode.

Under such circumstances, the cathode current is drawn through one diode 7 connected to its cathode 3 and detected by a detection circuit 8.

When receiving such current, the detection circuit energizes an output 9 which is connected to an alarm 10 to provide an audible and/or visual alarm.

FIG. 2 shows a display device that is an advanced version of the display device shown in FIG.
(However, only three of them are shown).

A common cathode drive unit and decoder 4 is provided in all display devices 1, each cathode being connected to each member of the set of lines 11 energized by the unit 4.

Line 11 is the same as circuit connection 6 in FIG. 1, and diode 7 is provided as described above and connected to the input of detection device 8.

When any one of the segments of the seven segment device 1 fails, current is drawn through the diode 7 and detected by the circuit 8.

As a result, the output signal is provided over line 12 to an alarm unit (not shown).

The output signal is also supplied to the drive unit 4 in such a way that the entire output of the drive unit is supplied with a cathode voltage.

This means that all lines 11 receive the cathode voltage and each display device shows the number 8 except for the failed device.

The device of FIG. 2 is specifically designed for use as an indicator array in the nozzle handle of a liquid fuel distribution pump.

The display is to indicate the volume of fuel dispensed, the cost of the fuel when the fuel is dispensed, and the unit price of the selected fuel.

There are therefore 13 display digits and therefore 13 display units 1.

To reduce the number of control lines required to display the 13 digits, a time division multiplex display is used.

To this end, each display device 1 receives an anode voltage from a selection circuit 13, which is controlled by a latch 14 and four bit counters 15, so that the display devices can be operated by sequentially applying anode voltages in a periodic sequence. I am forced to do it.

In order to display the appropriate numerical value in each display, the drive unit 4 is controlled by a latch 17 which is set by four bit registers 18 in synchronization with the periodic display sequence.

In this way, when an individual display device receives an energizing anode voltage, the cathode voltage pattern applied to the cathode of the device is adapted to provide the required display.

Control signals for the numerical values are supplied via line 19 in the form of a series of binary digital signals.

The latch signal is provided via input line 20 and the display select signal is provided via input 21.

Input line 22 is for clearing counter 15.

In addition to the fault signal line 12, there are only four input lines for controlling the thirteen display devices.

This is advantageous in this particular arrangement, because
This is because the number of input lines should be kept to a minimum for safety and to minimize the available space for input lines.

FIG. 3 shows the general arrangement of a gasoline filling station with a gasoline pump having the display device of FIG.

Although there are many gasoline pumps at the gas station, only one is shown as 23 for convenience.

All of the pumps are connected by a common data transmission link 24 to a central control unit 25 where a cashier is located to collect cash at the end of each transaction.

Pump 23 has a display 26 mounted on the pump body, which is the thirteen displays described with reference to FIG.

However, an additional display device may be added on the pump nozzle handle.

The display devices are also shown identically in the central control unit 25,
Again, 13 numbers are shown that are appropriate for the current dispensing operation.

This information is carried over the common data transfer link 24 in a time division multiplexed manner by a series of binary digital signals.

Each pump is interrogated in turn by the central controller and transmits the necessary information as a result of the interrogation.

This series of information is processed by central controller 25 in the same manner as described in connection with FIG. 2 to provide the necessary display.

FIG. 4 shows the nozzle of the pump 23 of FIG.

The nozzle has a handle with a seven segment display on it.

This device is entirely enclosed in a transparent epoxy resin block 27.

The display shows the current volume of fuel as it is dispensed,
Shows the total price as dispensed and the price per unit volume of the selected fuel.

A heat sink (not shown) is incorporated into block 27 to dissipate the heat generated by the seven segment display.

The five lines necessary for display and alarm signals are contained in a cable (not shown) attached along the pump hose.

[Brief explanation of drawings]

1 is a circuit diagram of a display device according to the present invention, FIG. 2 is a circuit diagram of another display device according to the present invention when used in a liquid fuel dispensing device, and FIG. 3 is a circuit diagram of a display device according to the present invention. 4 is a schematic diagram of the apparatus, and FIG. 4 is a perspective view of a nozzle of a distribution pump embodying the invention. 1 is a 7-segment display device, 2 is a common anode, 3 is a cathode,
4 is a drive unit, 5 is a terminal, 6 is a connection circuit, 7 is a diode, 8 is a detection circuit, and 9 is an output.

Claims (1)

[Claims] 1 A seven-segment display with a common anode and cathode for each segment, including a cathode driver connected to each cathode to supply cathode current to the appropriate segment when energized, and a series diode connected to each cathode. circuit connection,
A detection circuit connected to the circuit connections to draw current through each diode from each cathode drive in the event of a device segment failure, and an output connected to provide an alarm indication when current is received through the diodes. 7 segment display including.