DE3701681A1 - METHOD FOR BIDIRECTIONAL EXCHANGE OF SIGNALS BETWEEN A COMPUTER SYSTEM AND AN INQUIRY TERMINAL AND COMPUTER SYSTEM THEREFOR - Google Patents

Abstract

A computer system with one or more computers and an output drive connected with a polling terminal for a bidirectional exchange of signals is faced with the problem of reducing the volume required for the plug-in contacts and connecting lines, and of improving its reliability. This problem is solved in that output signals are alternatively transmitted during a first time to the output driver and from the output driver to a polling terminal through a single line, and that during a second time the output dirver is turned off and input signals are transmitted through the same line from the polling terminal to the computer system. The number of lines required is thus reduced by half, which has a beneficial effect on the necessary volume, and the total probability of failures is reduced through the elimination of additional plug-in contacts and lines that may be a source of disturbance in certain cases.

Description

The invention relates to a method for bidirectional Signal exchange between a computer system and one associated query terminal, in particular for security systems in motor vehicles, e.g. Anti blocking systems, air bags or belt tensioners, whereby the computer system at least one computer and one Output driver includes.

Such computers are used for monitoring, control and control of processes used. An application area is the control of security systems in Motor vehicles, such as anti-lock braking systems or passive Restraint systems, e.g. inflatable gas pillows (air bags),  which auto when the vehicle collides with an obstacle effective matically, or seat belts in the The moment of the impact can be tensioned (belt tensioners).

To display certain operating states and a loading Such computer systems are often used connected to a query terminal. Such an ab question terminal consists of an optical or acus table output signal generator and one mostly mechanical actuatable input signal generator.

An operating state relevant to the display can be a malfunction be in the computer program that blocks the program flow or falsified. Such a disturbance can e.g. by a circuit defect or through external influences, such as radio interference from transmitters, electrical discharges or switching impulses on one Pipeline network. The one with the input operation of the computer system can then consist of verifying a diagnostic routine start or the computer to a predetermined location to set and restart the program.

The connection of the query terminal to the computer follows over lines, which may over several Plug contacts must lead when the query terminal  from the computer due to operational margins conditions is far apart. Connection lines and plug contacts increase the Construction space and contribute to the deterioration of the sturgeon vulnerability to. This increases the installation space causes the distances between the plug must meet certain minimum values and thus stand in the way of any reduction. The susceptibility to failure can increase that Soiling the contact resistance between the Increase contacts, and by thermal or vibration Influencing influences on the conductor track or cable breaks or can open plug contacts.

The invention has for its object a method for bidirectional signal exchange between one Computer system and an associated with it question terminal to create the space of the computer systems and query terminal and increases the reliability of signal exchange.

This task is carried out in a procedure according to the Ober Concept of claim 1 by the in the characterizing Part specified features solved.  

Through the alternate transmission of the signals one and the same line is compared to otherwise usual signal lines a reduction to Half reached. Especially in the course of a reduction of data or control lines by other dimensions Every additional saving brings a percentage growing reduction in lines. This can be done in Borderline cases lead to the use of a more computer system with a corresponding interrogator facilitated and other applications be opened.

The associated with a reduction in the lines Reduction in spatial dimensions also contributes a decrease in mass. With computer systems, the strong mechanical loads in the form of ver are subject to delays or accelerations in this way the security against mechanical Zer disturbances are increased. It also takes the total probability of malfunctions by opening the Plug connections, wire breaks, vibrations, Temperature voltages as well as electromagnetic on run off.

With the reduction in installation space and the reduction of Lines also reduce manufacturing costs  of such computer systems, which is particularly the case with Bulk products cheap on cost calculation affects.

In a practical embodiment of the invention are transferred to the output driver output signals from deviating from a reference potential Potential or potentials formed. Besides, will the output driver when a Be pull potential out and when loaded with a potential deviating from the reference potential switched.

This measure will trigger the output driver by the output signals themselves. This makes a separate control of the Output driver via a control line. The issue drivers can then also be outside of a computer board or a computer case can be arranged without thereby the number of plug connections required increased between the computer and the output driver becomes. This version enables a larger Ge freedom of design in the arrangement of the modules. Also when generating control signals on the part the computer result in circuitry and  program-specific advantages.

For a computer consisting of several computers system, the output signals of the computers are preferred logically linked to the output driver wear and the calculator will refer to the first and second period of time synchronized.

If the operating display is the display a malfunction, the logical Link executed as an OR link. At at their operating states can also be an exclusive or an AND link can be beneficial. The link allowed the same output driver for all existing ones To exploit computers of the computer system. Are there multiple computers within a spatial complex arranged, so can the logical links contribute to line capacities and connector savings.

The input and output signals are preferred formed by static potentials and the first The time span is measured much longer than that second period.  

This configuration enables static signals on the input and output side directly without coding show or enter. This procedural note too times thus simplifies the computer systems including query terminal and thus indirectly an increase in reliability through reduction the number of possibly susceptible modules. The dimensioning of the first period as essential inertia is shorter than the second period against the human senses by the Impression is given that the output signals constantly queue.

In a practical embodiment, the ver ratio of the first to the second period about 100: 1.

This dimensioning ensures that the sub break of the output signal remains unnoticed. Is considered Output signal generator e.g. use an optical display det, this creates the impression of a flicker-free appearance show. In contrast, the short one is enough for one signal input time available, the signal safe entry.

In a practically executed invention  Procedure is the cycle of the first period 100 ms and the second period 1 ms.

This time is measured so that even with one brief actuation of the input signal generator is run through at least once the second period. This is usually sufficient for safe operation out. Only one intentionally extremely briefly featured actuation can cause the case that the Input signaling device only during the first period is activated and therefore no transfer to the Computer system. However, this case can remain considered.

The invention further relates to a query terminal for bidirectional signal exchange connected computer system, the at least one Rech ner and an output driver, especially for Safety devices in motor vehicles, e.g. Anti-lock braking systems, air bags or belt tensioners, where at the output of the computer or outputs of the computer via the output driver and a line with the Ab are connected to the question terminal. In this regard, the Invention based on the task of a query terminal for a bidirectional signal exchange ver  tied computer system to create that opposite previous solutions a reduction in the construction groups reached the total space occupied and at the same time the reliability of the signal exchange elevated.

This task is performed in a computer system according to the Preamble of claim 7 by the in the mark specified features solved.

The invention enables alternate transmission of input and output signals on the same line. Since the output of the output driver is directly related to the input connection of the computer can be omitted Computers where the output driver is on the same Board as the calculator is arranged, the necessary a separate connector for the input signal line. The for the exchange of signals between the computer and the query terminal The number of lines and plug contacts is reduced by half. Accordingly, the construction space of the computer, in particular by the number the plug contacts is specified, reduced.

Also the number of wires in a wire harness for connection  the sub-assemblies serving cables will be there at decreased. In borderline cases, these measures can be taken help with the use of computer systems Ease query terminal and new application areas offer to develop.

The reduction of plug contacts and lines ver also reduces the probability of default by ver dirty or open plug contacts and cables breaks. Based on the consideration that each plug contact and each line the same probability of failure and is subject to such a fault the function of the entire computer system is impaired the probability of failure can be determined by Reduction of these sources of interference can be reduced.

By reducing the spatial dimensions occurs also a decrease in mass. Will the calculator system mechanical stresses, e.g. Ver exposed to delays or accelerations, so ver wrestles through those obtained with the invention Properties also the risk of mechanical Zer disorder.

The one for alternating switching of the output driver  and the input or inputs on the line required switches including the one controlling them Switching signal generator can be both separately physical assemblies as well as through a rake program and that in the computer or computers anyway existing assemblies can be realized. The last Possibility is preferable as it is in line with the demand for a reduction in space requirements stands.

The solution according to the invention is in the same way Computer systems with one and with multiple computers applicable.

In a practical embodiment, the output driver by the queue at the output of the computer Signal or by the at the outputs of the computer standing signals can be switched on and off.

This measure will trigger the output driver by the output signals themselves. A separate control via an additional Control line is unnecessary. Even if the issue driver on the same board as the computer an additional tax port is omitted  of the computer.

The control of the off is particularly easy if the output driver is at Applying a reference potential off and at Applying one from the reference potential switch potential is switched on.

Such an output driver is suitable for control with digital signals in which a potential state the switched-off operating state of the output driver and another potential state when switched on Operating condition corresponds. The connected computer is able to output driver without additional Control coding measures and at the same time and turn off.

In a practical implementation of the invention the output driver with an open collector output (Open Collector).

This type of output circuit enables the output of the output driver regardless of its control to reference potential without causing damage can arise. This will cause any, un  synchronized actuation of the input of the Ab question terminals.

Does the computer system include several computers that are connected to the should communicate with the same query terminal it is expedient to use a lo gian link to the output driver connect and the computers regarding the switching signals synchronize their switching signal generators.

In this way, savings on lines and Switch contacts are made. This is special possible if the computers are spatially adjacent are ordered. For uniform input and output to keep time, the computers are synchronized. The effort on the part of the query terminal is there through reduced.

The computers are preferably in the form of static output trained signal transmitter and input signal receiver.

With this type of signal transmission, a high Transmission security against interference, especially achieved with longer cable routes. Also allowed the signal transmission a direct control of off signaling devices as well as a direct processing of the  Signals from input signal generators.

In a practical embodiment of the invention Computer system, the query terminal includes an off signal light and an input signal switch, with the input signal switch between the line and the reference potential is switched while the Output signal light between the line and one of potential deviating from the reference potential, preferably wise supply voltage potential, is switched.

These output and input signal transmitters are for the An control with static potentials suitable, un complicated and robust in construction, cheap to manufacture position and are characterized by a small space needs out.

In a further development of the invention, the switching ratio of the switching signal generator so that the first Period is much longer than the second. At a practical embodiment is the switching ratio of the first to the second period 100: 1.

This dimensioning ensures that the interruption the output signal goes unnoticed. Used as an expense signal generator uses an optical display, so ent  is the impression of a flicker-free display. The on the other hand, the brevity is sufficient for signal input available time, the signal input perform safely.

The period of the switching signal is preferably generator with approximately 100 ms.

This time is chosen so that even with a short timely actuation of the input signal generator at least once the second period is run through. This is usually sufficient for safe operation.

In a practical computer system, the output driver includes an operational amplifier designed as a comparator. A non-inverting input is fixed by means of a voltage divider formed from resistors 42 and 44 to an H potential that can be output from the logic logic circuit. An inverting input is connected to the output of the logic logic circuit and to a resistor which is at reference potential. An output is finally connected to the common line and a resistance to a supply voltage potential.

The output driver executed in this way combines the proprietary in the performance level to coordinate a Output signaling device with a switch that when over of a given potential abruptly its polarity at the output changes. In this way a defined output signal is obtained, the no uncertainties about the switching status open leaves. Tolerances in the level of the output signal the logic logic circuit can look like this be compared.

Developments of the invention and advantageous Aus management forms result from the claims of further description and the drawing, which is an off management example of the invention illustrated in more detail.

Show in the drawing

Fig. 1 is a block diagram of the OF INVENTION dung,

Fig. 2 shows an embodiment of the invention with an output driver and a query terminal with dis kreten components,

Fig. 3 is a graphical representation of the timing of different operating states of the potential of the line using the example of the embodiment shown in Fig. 2.

In Fig. 1, a query terminal 10 for a mutual signal exchange with a computer system is shown, the computer system comprising two computers A and B , and an output driver 12 . Outputs 14 of the computers A , B are connected via the output driver 12 and a line 16 to the query terminal 10 and the query terminal 10 is connected via the same line 16 to inputs 18 of the computers A and B.

The computers A and B in turn are designed to achieve the object of the invention as switching signal generators 20 and switches 22 , which is indicated by functional blocks inside the computer A , B identifying frames. The actual data processing takes place via a function block called central unit 24 .

The switches 22 are designed so that either the input 16 or the output 14 to the line 16 is switched through. The outputs 14 of the computers A and B are connected to the input of the output driver 12 via a logic logic circuit 28 , which is embodied here in the form of an OR connection implemented with diodes. Alternatively, dashed lines indicate control lines that lead from the switch 22 to the output driver 12 . This is to show that the output driver 12 can be switched on and off by the computers A and B. The control lines are linked like the signal lines by a logic logic circuit 26 in the form of an OR circuit. The control lines indicated by dashed lines are not present in the preferred embodiment since the output driver 12 is switched on and off by the output signals themselves.

A preferred field of application for such an arrangement is security systems in motor vehicles. The computers A and B are used to evaluate measured values, for example acceleration and deceleration values, and to use them to obtain control signals with which actuators are controlled. For your own function control and that of the other computers, computers A and B run test routines from time to time. If a malfunction is determined, this operating state is displayed on the query terminal 10 .

The driver who has become aware of the malfunction now has the option of issuing a diagnostic request by actuating an input signal generator from the query terminal 10 , which causes the computer to determine whether the malfunction can be remedied or not. If the fault can be remedied, the indicator goes out, if it cannot be remedied, the indicator remains and signals the driver to immediately go to the workshop.

In this application, the signal exchange between the computers A and B on the one hand and the output terminal 10 on the other hand takes place in the following manner. As long as there is no disturbance, the outputs 14 are at reference potential. The output driver 12 is switched off and an output signal generator of the interrogation terminal 10 is not in the excited state.

If a fault occurs, one of the outputs 14 of the computers A , B or also both outputs 14 acquires a potential that is different from the reference potential, for example H potential. Regardless of which computer A , B the fault message originates from, the output driver 12 is switched on by the logic circuit 28 from the output signal and the output signal reaches the query terminal 10 via the line 16 . An output signal is then placed in the excited state.

The time period in which the output signal is applied to the output driver is determined by the switching signal generator 20 , which connects the output 14 to the control line 16 only for a first time period by switching on the output driver. In a second period of time, which is of considerably shorter dimensions, line 16 , on the other hand, is switched to input 18 .

In a practical implementation of the invention, the ratio between the first and second time periods is 100: 1 and the cycle of the time periods, which corresponds to the period of the switching signal generator 20 , is 100 ms. This gives the driver the impression that the output signal generator of the query terminal is continuously excited.

If the driver now actuates the input signal generator, nothing happens during the first period. In contrast, a diagnostic routine is started during the second period in which the line 16 is connected to the input 18 of the computers A , B. After their termination, the output signal and thus the display by the output signal generator of the interrogation terminal is either maintained or switched off.

If the input signal transmitter is actuated only during the first time period, then no input signal can reach the input 18 . However, this option is normally excluded, since the short cycles of 100 ms mean that it can be assumed that the second time period will also be run through at least once during the actuation period. An intentionally too short actuation need not be taken into account here.

In the embodiment shown in FIG. 2, computers A and B are only designed as blocks, since their design corresponds to that shown in FIG. 1. The output driver used here is a comparator 38 , the non-inverting input 14 of which, through a voltage divider consisting of resistors 42 and 44, takes on a potential which lies between a reference potential 38 and an H potential of the computers A , B. The inverting input 46 is connected to the output of the logic circuit 26 . An output 50 of the comparator 38 , which leads out as an open collector output, is connected to the line 16 and additionally via a resistor 52 to the supply voltage potential 34 .

The query terminal 10 comprises an output signal lamp 30 as an output signal generator and an input signal switch 32 , which can also be designed as a button, as an input signal generator. The lamp 34 is arranged between the line 16 and the supply voltage potential 34 , while the switch 32 lies between the line 16 and the reference potential 36 .

If the output driver 12 is not driven, its input 46 is pulled through the resistor 48 to reference potential 36 . The potential at input 40 is then higher than that at input 46, and output 50 is pulled to supply voltage potential 34 via resistor 52 due to the lack of activation of the end transistor. This is also the line 16 to Ver supply voltage potential 34 and the lamp 30 is turned off.

In contrast, if the input 46 of the comparator 38 is controlled with an H potential of the logic circuit 28 , the end transistor of the comparator 38 is turned on and pulls the potential at the output 50 to a value between the supply voltage potential 34 and the reference potential 36 . The lamp 30 is switched on.

If the switch 32 is actuated, the potential of the line 16 is in any case drawn to the reference potential 36 . This switching state is evaluated by the latter as a diagnostic request during the second period in which the potential of the line 16 reaches the input 18 of the computers A and B.

An actuation during the first period of time neither influences the computers A , B nor does it impair the function of the comparator 38 . Only the lamp 30 is excited during actuation, since it is placed between the supply voltage potential 34 and the reference potential 36 by the actuation.

The graphical representation of the time sequence of various operating states as potential on line 16 shown in FIG. 3 illustrates several cases. Two cycles of the first and second time period are shown, the time periods being designated by the numbers 1 and 2 .

In Fig. 3a the case is shown in which no fault message has occurred. Accordingly, the potential of line 16 is continuously at supply voltage potential 34 .

In Fig. 3b is a fault. The potential of the line 16 is during the first time period between the power supply potential and the reference potential 34 and 36 during the second period to supply voltage potential 34th In Fig. 3c is again a malfunction. In the course of the first period, the switch 32 is switched on and remains actuated for a time t . This eliminates a previously signaled fault. The potential of the Lei device 16 is before actuation of the switch 32 between the supply voltage potential 34 and the reference potential 36 , during the time t when the switch 23 is actuated to the reference potential 36 and after the switch has been opened and the fault has been rectified to the supply voltage potential 34 .

A fault is also signaled in FIG. 3d. However, this cannot be remedied. In contrast to the illustration in Fig. 3c, after opening the switch 32, the potential of the line 16 between the supply voltage potential 34 and the reference potential 36 remains.

Finally, Fig. 3e shows the case that no fault is signaled, but the switch 32 is still operated. Here is the line 16 before and after actuation of the switch 32 to the supply voltage potential 34 and when the switch 32 is actuated to the reference potential 36 .

Claims (17)

1. A method for bidirectional signal exchange between a computer system and a related ver query terminal, in particular for security devices in motor vehicles, such as anti-lock braking systems, air bags or belt tensioners, the computer system comprising at least one computer and an output driver, characterized in that alternately in a first period of time output signals are transmitted to the output driver and from this terminal via a line to the query and that in a second period the output driver is switched off and input signals are transmitted from the queried terminal to the computer system via the same line. 2. The method according to claim 1, characterized records that those transferred to the output driver Output signals deviate from a reference potential appropriate potential or potentials are formed and that the output driver when loaded with a reference potential and when applied with a Po deviating from the reference potential is switched on. 3. The method according to claim 1 or 2 with a computer system consisting of several computers, because characterized in that the output signals of the Rech logically linked to the output driver and that the computers with respect to the first and the second period are synchronized. 4. Method according to one of the preceding An Proverbs 1-3, characterized in that the one Output and output signals through static potentials are formed and that the first period is essential is longer than the second period. 5. The method according to claim 4, characterized indicates that the ratio of the first to the second  Time period is approximately 100: 1. 6. Method according to one of the preceding An sayings 1-5, characterized in that the cycle the first time span approx. 100 ms and the second time span is approximately 1 ms. 7. Computer system connected to a query terminal ( 10 ) for a bi-directional signal exchange, which comprises at least one computer ( A , B ) and an output driver ( 12 ), in particular for safety devices in motor vehicles, for example anti-lock systems, air bags or belt tensioners, wherein an output ( 14 ) of the computer ( A ) or outputs ( 14 ) of the computer ( A , B ) via the output driver ( 12 ) and a line ( 16 ) with the query terminal ( 10 ) are connected, characterized in that the Query terminal ( 10 ) are connected via the same line ( 16 ) to an input ( 18 ) of the computer ( A ) or inputs ( 18 ) of the computer ( A , B ) and the computer or computers ( A , B ) as a switching signal generator (s ) ( 20 ) and switches ( 22 ) for alternately switching the output driver ( 12 ) during a first period and the input ( 18 ) or the inputs ( 18 ) during a second period of time are formed on the line ( 16 ). 8. Computer system according to claim 7, characterized in that the output driver ( 12 ) by the signal present at the output ( 14 ) of the computer ( A ) or by the signals at the outputs ( 14 ) of the computer ( A , B ) can be switched off and on. 9. Computer system according to claim 8, characterized in that the output driver ( 12 ) off when applied with a reference potential and is turned on at loading with a potential deviating from the reference potential. 10. Computer system according to claim 9, characterized in that the output driver ( 12 ) has an open collector output (open collector). 11. Computer system according to one of the preceding claims 7-10, which comprises several computers ( A , B ), characterized in that the outputs ( 14 ) of the computer ( A , B ) via a logical link ( 28 ) with the output driver ( 12 ) are connected and the computers ( A , B ) are synchronized with regard to the switching signals of their switching signal generators ( 20 ). 12. Computer system according to one of the preceding claims 7-10, characterized in that the computer or computers ( A , B ) are designed as a static (r) output signal transmitter and input signal receiver. 13. Computer system according to claim 12, characterized in that the query terminal ( 10 ) comprises an output signal lamp ( 30 ) and an input signal switch ( 32 ) and that the input signal switch ( 32 ) between the line ( 16 ) and a reference potential ( 36 ) while the output signal lamp ( 30 ) is connected between the line ( 16 ) and a potential ( 34 ) that deviates from the reference potential ( 36 ). 14. Computer system according to one of the preceding claims 7-13, characterized in that the switching ratio of the switching signal generator ( 20 ) is dimensioned such that the first period is significantly longer than the second. 15. Computer system according to claim 14, characterized ge indicates that the duty cycle of the first for the second period is approximately 100: 1. 16. Computer system according to one of the preceding claims 7-15, characterized in that the period of the switching signal generator ( 20 ) is approximately 100 ms. 17. Computer system according to one of the preceding claims 7-16, characterized in that the output driver ( 12 ) comprises an operational amplifier formed as a comparator ( 38 ), the non-inverting input ( 40 ) of which by means of resistors ( 42 ) and ( 44 voltage divider formed) is set to a lying between the reference potential and a dispensable from the logical operation circuit (28) H- potential potential, the inverting input (46) to the output of lo cal logic circuit (28) and a lying to reference potential resistor (48) is connected and the output ( 50 ) is connected to the line ( 16 ) and a resistor lying against a supply voltage potential.