GB2325554A - Data display system - Google Patents

Abstract

A data display system (1) has a processor (6) which receives data from sensors (2) in real time. It processes this data in real time by use of a configuration database (8), a real time database (9), and a manual override database (10). The configuration database (8) is used for generation of a simulation display at an administration interface (11) to simulate signs (13). The automatic messaging operations may be overridden by administration personnel via the interface (11). The displayed information may relate to traffic, parking spaces, cinema schedules, or travel.

Description

A Data Display Svste" The invention relates to a data display system for display of data in real time indicating information which relates to such things as traffic, parking spaces, cinema schedules, bus or train station departure and arrival information etc.

There have been many developments in data display technology for providing discreet light sources which can be energised in particular patterns for display of data. For example, GB 220 6435 (A/S Designs) describes a changeable data display assembly and WO 94/07231 (Mobitec) discloses a modular display element. Such elements or assemblies may be easily mounted in a frame for control by driver circuits. US 545 1979 (Adaptive Micro Systems), US 492 9936 (Home Security System), and CA 210 9405 (Banks) all describe various control methodologies at the display sign for display of information.

While developments such as these have been quite significant at improving the versatility of the nature of the data which can be displayed, there is a need for improved integration of sign systems so that there is effective centralised control, irrespective of the size of the system. Such control would allow integration of the system with wider systems which provide data so that the signs may be used more comprehensively and effectively.

The invention is therefore directed towards providing an improved sign display system which provides more effective centralised control, with flexibility.

According to the invention, there is provided a data display system comprising:at least one sign, each comprising a logic circuit and a driver circuit driving light sources, the logic circuit comprising means for receiving serial data bytes, converting the bytes to parallel format, validating messages, converting the messages to serial format and transmitting corresponding display commands to the driver circuit; a central controller comprising: a sensor interface comprising means for communicating with data sensors; a sign interface comprising means for communicating with at least one sign; a configuration database storing sign and sensor configuration data including location and characteristics of the sensors and signs; a real time database for storing real time messaging data; and a processor comprising means for: directing repeated polling of the sensors according to the configuration database, validating received sensor data, processing the sensor data according to the real time database and any received override instructions, transmitting processed data to the signs with start and end of message bytes, and using configuration data to generate sign simulation displays at the central administrative location before real time processing and subsequently using processed data during real time processing.

In one embodiment, the logic circuit of each sign comprises means for monitoring an off time, and means for updating the driver with a previous message if an off time is reached, to avoid sign flicker.

Preferably, the logic circuit comprises means for storing the sign address both in manual switches and in memory updateable via the processor of the central controller.

In one embodiment, the processor comprises means for operating in the following four multi-tasking cycles: detecting any override instructions, updating simulation displays at the administration interface, polling the sensors processing received data, and transmitting processed data to the signs, and logging events.

In a further embodiment, the processor comprises means for updating an override database with override instructions.

In another embodiment, the frequency of monitoring the administration interface is the range 75 ms to 125 ms.

Preferably, the frequency of updating this simulation screen is in the range 100 ms to 1 second.

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which: Fig 1 is a schematic representation of a data display system of the invention; Fig 2 is a flow chart illustrating operation of a central controller of the system; Figs 3 and 4 are block diagrams illustrating logic and driver circuits of a particular sign; and Figs 5, 6 and 7 are flow charts illustrating operation of the logic circuit in communication with the central controller.

Referring initially to Fig 1, there is shown a data display system 1 of the invention. The system 1 is for capture of information from car parks indicating their usage, for processing this information, and for displaying car park availability information on signs at prominent street locations. However, the system of the invention could be applied to any other use in which data is captured, processed, and displayed in a cinema complex.

The system 1 interfaces with a set of sensors 2 which are mounted in car parks and monitor the passage of vehicles into the car parks. The sensors are of the infra-red, type, but could alternatively be located on gates or other barriers. The system 1 comprises a set of modems 3 connected to a central controller 4. The controller 4 has a sensor interface 5 connected to the modems 3, a processor 6, and a sign interface 7. There are three primary databases accessed by the processor 6, namely a configuration database 8, a real time database 9, and a manual override database 10. The processor 6 is also connected to an administration user interface 11.

The sign interface 7 is connected to a set of modems 12 which are programmed to communicate with a number of signs 13. Each sign 13 comprises a logic circuit 14, a driver circuit 15, and display elements 16 which are shown in one illustrative example.

Referring now to Fig 2, operation of the processor 6 is now described in detail. This is an important aspect of the invention as it provides comprehensive central control in a flexible manner. The process is indicated generally by the numeral 20 and in step 21 the processor reads configuration data from the database 8. The configuration data includes the physical location of the sensors 2 and the signs 13, and for each sign it stores the standard text which is displayed, together with characteristic data on the display elements.

Other data includes directional display, finger post display, sensor address, name, location, leased line number, modem number, and configuration status details. In step 22, the processor 6 communicates with the interface 11 to display sign simulations which indicate the sign locations and their standard data. In this way, administrative personnel can see at a glance the exact nature of the signs being controlled. At this stage only standard text and sign characteristic data is displayed during simulation - the data being also displayed at a later stage.

In step 23 of the process, the processor 6 sets up multi-tasking timers for four parallel tasks to provide for comprehensive and flexible control. According to an event timer 24, the processor 6 operates to apparently operate in parallel by performing a number of tasks in series, but at regular intervals so that buffers for all tasks are maintained. In step 25 the processor 6 checks the interface 11 to determine if any manual overrides have been inputted. This check occurs every 100ms, but may be in the range of 75 to 125 ms. In step 26, the processor 6 updates the interface 11, which is displaying the sign simulations. This update involves updating with the data which is being transmitted to the signs via the sign interface 7. The simulation update occurs every 500ms, but may be in the range 100 ms to 1 second.

In step 27, the processor 6 directs the sensor interface 5 to poll the sensors. Upon receipt of data from the sensors, in step 28 the processor 6 validates and processes this data and in step 29 it transmits the processed data to the sign 13. Each cycle takes 30 seconds. The reason for the relatively long cycle for this stage is not only the level of processing which is required, but also the communication delays which may arise. To process the data in step 28, the processor 6 refers to the configuration database 8 to determine the characteristics of transmission of data such as the relevant protocol message sizes, the nature of the end of message and start of message bytes etc. The processor 6 also refers to the real time database 9 to retrieve the current data.

The real time database 9 contains a listing of the messages currently associated with each sensor. A validated communications response message is associated with a particular device and used to update the real time database accordingly. An example of processing is that in the event of a car park reaching its nearly full state, the response information is compared with a nearly full status listing in the configuration database 8. If the capacity is reached for nearly full status, the real time database is updated with a "nearly full" flag.

An important aspect of the processing step 28 is that the processor 6 also refers to the manual override database 10 which may store override data retrieved in step 25. This allows flexible control as users may simply override the automatic operation according to circumstances.

In step 30, the processor stores data and logs events. System status data is logged separately as system events and device faults, together with time and date stamps. Events such as "communications break" and symbol override are examined separately to device faults such as "lamp fault" or "battery back-up failure".

This four-event cycle is terminated according to the timer in step 31, and subsequently in step 32, the processor 6 saves information to disk. The three main types of data saved are: (a) System setup data including sensor names and other parameter values and communications values.

(b) Addresses of remote computers which may provide an input.

(c) Screen display data.

The step 32 involves saving updates to some of these data categories.

The data is transmitted via the processor 6 to the signs 13 in serial format comprising a series of bytes with end of message and start of message bytes to delineate particular messages. This data is received in the logic circuit 14 of the addressed sign 13.

As shown in Figs. 3 and 4, each logic circuit 14 comprises a CPU 40, a power supply 41, a real time clock 42, a reset circuit 43, an EPROM 44, and a RAM 45. In addition, there are dip switches 46 which are depressed to set the address of the particular sign. The modems 12 communicate through an RS 485 convertor 47, which is in turn connected to a serial/digital convertor 48 which is in turn connected to the CPU 40. A display data and timing circuit 49 converts the CPU parallel data to serial format for transmission to the display driver circuit 15, shown in Fig 4. The driver 15 comprises an 85-way shift register 50 connected by a column driver to LED modules 51. In this embodiment, there are five rows and seventeen columns, one LED module being shown as indicated by the numeral 51. The driver 50 comprises a power supply 52.

Referring now to Figs 5 to 7 inclusive, the manner in which the logic circuit 14 operates is now described in detail. The process is indicated generally by the numeral 60 and begins with step 61 when activated. In step 62 the CPU 40 clears the RAM 45 and reads the address switches 46 in step 63. As indicated by the decision step 64, the switches 46 are reset and in step 65 the CPU 40 begins reading the RAM 45 and continues with each location as indicated by the steps 66, 67 and 68 until an address is detected. When detected, a preprogrammed acknowledgement message is transmitted back to the processor 6 in stop 70. Alternatively, a fail message is transmitted as indicated by step 71. This allows versatility as the address may be set in either solid state devices such as the switches 46 or in RAM 45, having been uploaded by the processor 6.

In step 75, the CPU receives the first serial byte and determines if it is a start of message byte and if so clears the serial buffer in the UART convertor 48. If it is not a start of message byte, the CPU 40 simply reads the next byte as indicated by the decision 77. If an off-time has been reached without receipt of a start of message byte the CPU 40 leaves the display sign blank as indicated by step 79.

Once the buffer has been cleared in step 78, the CPU 40 retrieves the next serial byte in step 80 and stores it in a buffer mapped in the RAM 45 in step 82. The steps for storage of bytes are repeated as indicated by the decision step 83 and 82 until an end of message byte is detected. However, if the off-time has been reached, the CPU 40 simply updates the display with a previous message, which is stored in the mapped part of the RAM 45. This is indicated by a step 87.

In the decision step 85, the CPU 40 determines if the message is a synchronisation message, and if so it updates the off-time in step 86 and then continues again from step 75.

If the message is not a synchronisation message, in step 90 the CPU 40 checks the address which is incorporated in the message against its own address and then receives the text message in step 91 from the RAM 45, this having been written byte-by-byte in steps 80 - 82.

In step 92, CPU 40 carries out a cyclic redundancy check (CRC) and if this fails it sends an error message in step 93 to the controller. If the CRC check is positive, in step 94 the controller 40 transmits an acknowledgement signal to the processor 6 and if the reply indicates that the message is to be run in step 97 the CPU generates a message from the stored text and transmits it to the driver.

It will be appreciated that the logic circuit operates to ensure data integrity, while at the same time ensuring that flicker does not arise by continuously monitoring the offtime and updating the display if the offtime is reached. The offtime can be easily updated by use of synchronisation messages, and this also provides for versatility in the system.

It will also be appreciated that the central processor 6 performs very fast real time message control operations while at the same time allowing a large degree of versatility by the way in which it refers to the various databases. It also allows easy and simple user control by use of the supreme simulations.

The invention is not limited to the embodiments hereinbefore described, but may be varied in construction and detail within the scope of the claims.

Claims (8)

1. A data display system comprising: at least one sign, each comprising a logic circuit and a driver circuit driving light sources, the logic circuit comprising means for receiving serial data bytes, converting the bytes to parallel format, validating messages, converting the messages to serial format and transmitting corresponding display commands to the driver circuit; a central controller comprising: a sensor interface comprising means for communicating with data sensors; a sign interface comprising means for communicating with at least one sign; a configuration database storing sign and sensor configuration data including location and characteristics of the sensors and signs; a real time database for storing real time messaging data; and a processor comprising means for: directing repeated polling of the sensors according to the configuration database, validating received sensor data, processing the sensor data according to the real time database and any received override instructions, transmitting processed data to the signs with start and end of message bytes, and using configuration data to generate sign simulation displays at the central administrative location before real time processing and subsequently using processed data during real time processing.

2. A system as claimed in claim 1, wherein the logic circuit of each sign comprises means for monitoring an off time, and means for updating the driver with a previous message if an off time is reached, to avoid sign flicker.

3. A system as claimed in claims 1 or 2, wherein the logic circuit comprises means for storing the sign address both in manual switches and in memory updateable via the processor of the central controller.

4. A system as claimed in any preceding claim, wherein the processor comprises means for operating in the following four multi-tasking cycles: detecting any override instructions, updating simulation displays at the administration interface, polling the sensors processing received data, and transmitting processed data to the signs, and logging events.

5. A system as claimed in any preceding claim, wherein the processor comprises means for updating an override database with override instructions.

6. A system as claimed in any preceding claim, wherein the frequency of monitoring the administration interface is in the range 75 ms to 125 ms.

7. A system as claimed in any preceding claim, wherein the frequency of updating this simulation screen is in the range 100 ms to 1 second.

8. A system substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.