EP2900539B1 - Circuit arrangement for revealing light signal errors - Google Patents

Description

The invention relates to a circuit arrangement for error disclosure in a light signal, in particular for railway safety systems, with an eventual error reversible shutdown electronic signal transmitter and designed for incandescent control unit for driving and monitoring the signal generator, the error disclosure includes a fault differentiation between line-induced interference voltage and error of the signal generator ,

The following description refers essentially to light signals for railway safety systems, without the invention being restricted to this application. Rather, an application is conceivable, for example, in other traffic systems or in the industrial sector.

In the case of incandescent light signals, the lines are dimensioned in such a way that when the signal leads are influenced, the influencing current flows through the incandescent lamp and this influencing current does not cause the incandescent lamp to light up. Actuators designed for incandescent light signals typically evaluate a signal current to detect a fault or the proper functioning of the light signal.

When incandescent signalers are replaced by electronic signal transmitters, for example for LED light sources, the influencing current causes the electronics to operate, but due to the low energy level of the influence it is not possible to start the signal generator. The signal voltage drops during the start attempt and the reversible switch off signal generator starts the next attempt to start.

This start sequence is also given in the case of a low-impedance fault in the signal generator. Due to the impedance of the signal line, the signal voltage breaks down when the electronics are switched on. In this case, a very high current flows, which is rated for the control part not as an error, but as a valid signal stream. The electronics, however, can not measure the current due to the low voltage and, where appropriate, starts a new start attempt.

Due to the same starting behavior with error-free signal transmitter with influence and signal generator with low-impedance error, the cause of the error can not be detected. Consequently, it must be ensured that the electronic signal transmitter can distinguish between signal generator voltage and influencing voltage in order to reveal not only the presence of an error but also the cause of the error.

So far, this problem has been solved in that at an excessively high current flow, the control element and at only a slightly increased current flow of the signal generator detects the error and transmitted to the control section. However, this error disclosure is not always ensured at higher impedances of the signal line, since there is a gap between the current flow detection by the control part and the current flow detection by the signal generator. This gap in the current flow detection is closed by the fact that the signal generator evaluates the current immediately after the start, that is, before the signal voltage collapses. For this purpose, signal generator-internal capacitors are required, which are charged by the control unit and provide the signal generator for a sufficient amount of power. After the start of the electronics of the signal transmitter with low-impedance error, high currents can thus be measured and used for error detection. The prerequisite is that the capacitors can store their energy for a sufficiently long time. However, the function of the capacitors is usually not tested.

The document EP 2 131 628 A2 shows a circuit arrangement according to the preamble of claim 1.

The invention is accordingly based on the object, the reliability of error differentiation between line-related To increase the influencing voltage and the low-impedance fault of the signal transmitter. In particular, independence from capacitive energy buffers is desirable.

According to the invention the object is achieved in that the signal generator is connected to a resistor arrangement such that at high-impedance signal generator, the signal generator voltage is greater than the influencing voltage. As a result of the resistor arrangement, the signal generator voltage and the influencing voltage are virtually pulled apart and thus distinguishable from one another. The resistor arrangement consists of consumers, which lower the influencing voltage. In the event of a fault, the voltage breaks down immediately after starting on the signal generator. The signal generator is thus high impedance. Thereafter, the voltage rises again, wherein the signal generator voltage of the high-impedance signal generator is greater than the influencing voltage by the resistor arrangement. With fault-free signal transmitter and influencing voltage, the influencing voltage is measured after high-ohm switching, while the signal generator voltage is measured when the signal transmitter is defective.

It is advantageous, above all, that the starting currents do not have to be evaluated and the capacitors required for this purpose as an energy source do not have to be dimensioned exactly and frequently checked. Only the dimensioning of the resistor arrangement must be determined in such a way that the signal generator only becomes so high-impedance that the influencing voltage remains smaller than the voltage at the signal generator.

When detected signal generator voltage and repeated failed attempts to start an error message to the control part by the high impedance switching of the signal generator, which due to the low signal current to a signal generator error, ie a fault of the module or a defective high-impedance terminal point in the signal cable area closes.

At influencing voltage, the threshold for detecting the signal generator voltage is not reached, so that no new start attempt takes place and no error message occurs.

According to claim 2, it is provided that the error differentiation between the signal generator voltage and the influencing voltage, a voltage threshold is applied, when exceeded an error of the signal generator and when it falls below an influence exists. Preferably, the voltage threshold is positioned approximately midway between the signal generator voltage and the bias voltage to achieve the most reliable error assignment possible.

In an advantageous embodiment according to claim 3, the resistor assembly is designed to be switched off, said shutdown is carried out according to claim 4 in particular in case of error disclosure. The correct error transmission to the actuator is thereby independent of any repercussions of the resistor assembly and is carried out as in the known error disclosure described above by the high impedance switching of the signal generator and thus the reduction of the signal current.

Figur 1

das Grundprinzip einer Signalanschaltung,

Figur 2

eine vereinfachte Darstellung des Grundprinzips gemäß Figur 1,

Figur 3

eine Signalanschaltung mit fehlerhaftem Signalgeber in der Darstellungsweise gemäß Figur 2,

Figur 4

ein Diagramm bezüglich des Einschaltverhaltens eines fehlerfreien Signalgebers,

Figur 5

ein Diagramm des Einschaltverhaltens mit fehlerhaftem Signalgeber und

Figur 6

ein Diagramm des Einschaltverhaltens bei Beeinflussung.

The invention will be explained in more detail with reference to figurative representations. Show it:

FIG. 1

the basic principle of a signal connection,

FIG. 2

a simplified representation of the basic principle according to FIG. 1 .

FIG. 3

a signal connection with faulty signal generator in the representation according to FIG. 2 .

FIG. 4

a diagram relating to the turn-on behavior of a fault-free signal generator,

FIG. 5

a diagram of the switch-on with faulty signal generator and

FIG. 6

a diagram of the switch-on behavior under influence.

FIG. 1 illustrates the connection of a signal generator 1 via a signal line 2, which is connected via a switch S1 to one of a, usually far from the signal transmitter 1 remote control part, which has a voltage source 3, with a signal voltage U1. In this case, U2 is the signal generator voltage and U3 is a line-induced influencing voltage. The signal generator 1, the signal generator voltage U2 and the impedance Z3 are assigned. The signal voltage U1 is switched by the control unit via S1 and the signal line 2 with the impedance Z1 to the signal generator 1. The influencing voltage U3 is permanently applied to the signal generator 1 via Z2.

für die Signalgeberspannung und $$U2=U3\frac{Z3}{Z2+Z3}$$

für die Beeinflussungsspannung.A correspondingly simplified circuit diagram shows FIG. 2 , The impedance Z1 of the signal voltage U1 is much smaller than the impedance Z2 of the influencing voltage U3. This is $$\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="imgf0001.png"\; state="\{\{state\}\}">U</figure-callout>}2=U1\frac{Z3}{\mathrm{<figure-callout\; id="1"\; label="Z"\; filenames="imgf0002.png"\; state="\{\{state\}\}">Z</figure-callout>}1+\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="imgf0002.png"\; state="\{\{state\}\}">Z</figure-callout>}3}$$

for the signal generator voltage and $$\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="imgf0001.png"\; state="\{\{state\}\}">U</figure-callout>}2=U3\frac{Z3}{\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="imgf0001.png"\; state="\{\{state\}\}">Z</figure-callout>}2+\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="imgf0002.png"\; state="\{\{state\}\}">Z</figure-callout>}3}$$

for the influencing voltage.

U2 of the signal generator voltage is much larger than U2 of the influencing voltage.

In FIG. 3 In addition, a signal generator error is displayed as Z3.1. As a result of this additional impedance Z3.1 of the signal generator 1, U2 of the signal generator voltage drops to the value of U2 of the influencing voltage. This is $$\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="imgf0001.png"\; state="\{\{state\}\}">U</figure-callout>}2=U1\frac{\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="imgf0002.png"\; state="\{\{state\}\}">Z</figure-callout>}3+Z3.1}{\mathrm{<figure-callout\; id="1"\; label="Z"\; filenames="imgf0002.png"\; state="\{\{state\}\}">Z</figure-callout>}1+\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="imgf0002.png"\; state="\{\{state\}\}">Z</figure-callout>}3+Z3.1}\approx U3\frac{Z3}{\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="imgf0001.png"\; state="\{\{state\}\}">Z</figure-callout>}2+\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="imgf0002.png"\; state="\{\{state\}\}">Z</figure-callout>}3}$$

Consequently, when measuring the voltage U2, it is not possible to distinguish between the influencing voltage and the signal generator voltage via the signal transmitter 1, which is not connected in a high-impedance manner.

In order to produce distinctness, the signal generator 1 according to the invention is connected to a resistor arrangement which reduces the influencing voltage.

The diagrams of FIGS. 4 to 6 each show 33 successively measured current / voltage value pairs. Current and voltage are not normalized. The measured value 637 in the three diagrams indicates a voltage threshold value 4 for distinguishing the influencing voltage from the signal generator voltage in the high-impedance state of the signal transmitter.

In FIG. 4 the signal generator 1 operates error-free with low voltage, so that via the signal generator 1 in stable continuous operation, a voltage drop is present, which results from Z1 and Z3. Since the signal generator 1 is not high-impedance, there is a higher voltage drop across Z1 than in the high-resistance state of Z3. For this reason, the measured voltage is smaller than the threshold value 4. The distinction between the signal generator voltage and the influencing voltage only occurs with a high-impedance signal generator.

In the FIGS. 5 and 6 different error states are shown, wherein the current / voltage value pairs with voltage value 0 indicate a collapsed signal generator voltage, so that the current values of these value pairs are invalid.

FIG. 5 shows a typical measurement history at low impedance error Z3.1 of the signal generator 1 and switched signal voltage U1. It can be seen that the voltage of the value pairs 1, 7, 8, 13, 14, 19 and 20 is very low, whereas the current is very high. The high current values in connection with the high voltage values of the value pairs 6, 12 and 18 exceed the threshold value 4, since the signal generator 1 at this value pairs 6, 12 and 18 has switched to the high-impedance state. Due to the high-impedance state in the aforementioned value pairs 6, 12 and 18 and the exceeding of the threshold value 4, the signal generator 1 is restarted. After multiple "false starts" in the value pairs 1, 7 and 19, the signal generator 1 switches at the value pairs greater than 22 high impedance, thus reporting its error to the control section. The signal generator voltage is greater than the threshold value 4.

FIG. 6 shows the switch-on behavior with influencing voltage (U3). If influenced, the signal generator 1 starts first and then switches to the high-impedance state. From the fifth value pair the signal generator 1 is high-impedance and the voltage remains below the threshold value 4, whereby the influencing voltage is detected. The switch S1 from the control is open in this state.

If the switch S1 closes from the control, the voltage exceeds the threshold 4 and the signal generator 1 starts as in FIG. 4 ,

Claims (4)

1. Circuit arrangement for revealing errors in the case of a light signal, particularly for railway safety installations, having an electronic signal transmitter (1), which disconnects itself reversibly in the event of an error, and an actuating part, designed for incandescent lamps, for actuating and monitoring the signal transmitter (1), wherein the revelation of errors comprises error differentiation between line-conditioned influencing voltage and errors in the signal transmitter (1),
   characterized in that
   the signal transmitter (1) has a connected resistor arrangement such that a high-impedance signal transmitter (1) prompts the signal transmitter voltage to be higher than the influencing voltage.
2. Circuit arrangement according to Claim 1,
   characterized in that
   a voltage threshold value (4) is provided for error differentiation between the signal transmitter voltage and the influencing voltage, with a rise above said voltage threshold value involving the presence of an error in the signal transmitter (1) and a drop below said voltage threshold value involving the presence of an influencing voltage.
3. Circuit arrangement according to either of the preceding claims,
   characterized in that
   the resistor arrangement is in disconnectable form.
4. Circuit arrangement according to Claim 3,
   characterized in that
   disconnection of the resistor arrangement is effected when errors are revealed.

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