DE102012105411B4

DE102012105411B4 - Use of a signature resistor element in a backup loop

Info

Publication number: DE102012105411B4
Application number: DE201210105411
Authority: DE
Inventors: Stefan Heimerl; Thilo Meisel
Original assignee: MECOMO AG
Current assignee: MECOMO AG
Priority date: 2012-06-21
Filing date: 2012-06-21
Publication date: 2014-04-03
Anticipated expiration: 2032-06-22
Also published as: DE102012105411A1; WO2013189483A1

Abstract

Use of a signature resistance element in a security loop, the signature resistance element comprising an electrically conductive body (K) which has a predetermined total ohmic resistance (RK) for a predetermined total length (Lges), the electrically conductive body (K) across its Total length (Lges) has a non-linear resistance-length characteristic.

Description

The present invention relates to the use of a signature resistive element in a fuse loop and, more particularly, to the use of a signature resistive element as used in the field of safety engineering as part of an electronic seal for monitoring closures against unauthorized opening.
In burglar alarm technology, for example, loop monitoring are known, which are designed with terminating resistors. However, these terminators have fixed resistance values and are thus known or easy to determine. Moreover, because the terminators are installed at the end of the loop, they can easily be inserted into the loop knowing the resistance value during manipulation to prevent an alarm when disconnecting the loop.
Further, in security engineering, electronic tags, seals, or seals are known which can be mounted on an object and monitored to prevent theft, unauthorized opening of a closure, or manipulation of the object. Such conventional electronic seals or seals usually comprise a resistance wire and an evaluation circuit, which detects the ohmic resistance of the resistance wire and triggers an alarm when the resistance changes.
The disadvantage here is that either the possibility of bridging the resistance wire consists of an equivalent resistance, whereby a manipulation on the electronic seal remains undetected, or an increased triggering false alarms occurs because the evaluation must be switched to a higher sensitivity to even the slightest resistance changes to address the resistance wire.
From the publication DE 403204 A For example, a high-voltage resistor is known which has a resistance graduation per unit length in order to avoid overvoltage phenomena and associated damage due to arcing. Here, the resistor may consist of a Schniewindt band, wherein a certain percentage of the entire band has a cross-sectional area which is reinforced compared to the rest of the band.
The publication US 2004/0075520 A1 discloses a strip interconnect, wherein the interconnect to standardize a current distribution, in particular for the occurring at a curve inside the interconnect increased current densities, different resistance values. In particular, the curve regions of the interconnect can be reinforced by additional layers, and respective sections of the curve regions can have materials with different resistance values.
Furthermore, from the document DE 6609710 U a controllable grinding resistance known, wherein a resistance value is non-linear and in particular exponentially variable. Here, the width or thickness and thus the ohmic sheet resistance is continuously or stepwise changed along a resistance layer.
From the publication DE 6610047 U Another conventional variable sliding resistance is known in which a resistance element is realized by a plurality of windings and at least a part of the windings is bridged by a resistance mass.
The publication JP 2011119392 A discloses a variable resistor, wherein on a substrate, an electrically conductive layer and thereon a plurality of electrically conductive pastes are printed tape-shaped. This gives a compact construction, even if the distance between a smallest and largest electrical resistance is increased.
Finally, from the publication DE 1465535 A a shunt resistor for security systems known, wherein the shunt resistor is arranged in parallel with a receiving relay. The shunt resistor consists of a resistance plate and arranged on it zigzag bands and has four terminals, which are connected to two supply terminals and two terminals of the receiving relay. Accordingly, the current through the shunt resistor can flow through both the resistance plate and the tapes, thereby reliably preventing erroneous triggering of an alarm.
The invention is the object of a forgery-proof sealing of closures easy and reliable to allow.
According to the invention, this object is solved by the features of patent claim 1.
Accordingly, a signature resistive element is used in a fuse loop, wherein the signature resistive element comprises an electrically conductive body having a predetermined total resistive resistance for a predetermined total length, the electrically conductive body being over its entire length has a non-linear resistance-length characteristic. Due to the non-linear distribution of the resistance across the electrically conductive body, it is not possible to detect and bridge a corresponding partial resistance at a manipulation point. The evaluation circuit can therefore be constructed simple and robust, yet any manipulation is reliably detected.
For example, the electrically conductive body over the entire length have a non-linear cross-sectional area distribution, whereby a random resistance distribution can be realized particularly cost.
Preferably, the electrically conductive body may have at least two longitudinal sections each having constant and mutually different cross-sectional areas, wherein the mutually different cross-sectional areas are formed by different outer dimensions and / or by recesses. The random resistance distribution can be particularly simple by z. As hammering, stretching or punching can be realized.
For example, the electrically conductive body over the entire length of a same material, whereby the manufacturing costs are further reduced.
Alternatively, the electrically conductive body over the entire length at least two materials having different resistivity, whereby a tamper-proof is further improved.
In this case, the electrically conductive body may further have a constant cross-section over the entire length, whereby further detection of a resistance value at a manipulation point is made more difficult.
Preferably, the electrically conductive body has a material with a low temperature coefficient less than 200 × 10 -6 / K and in particular Konstantan ™ , whereby the requirements for an evaluation circuit are further reduced.
Preferably, the electrically conductive body has a material having a high resistivity greater than 4.0 × 10 -7 Ωm, whereby a relatively large change in resistance per unit length is realized even with a relatively small overall length of the signature resistor element.
For example, the electrically conductive body may be formed in a fuse wire, fuse cable, circlip or safety pin, whereby suitable electronic seals or seals can be realized for a variety of applications.
In the further subclaims further advantageous embodiments of the invention are characterized.
The invention will be described below with reference to embodiments with reference to the drawings.
Show it:
1 a simplified side view of a signature resistor element according to a first embodiment;
2 a cross section of the signature resistor element according to 1 ;
3 a simplified view of a resistance-length characteristic of the signature resistance element according to 1 ;
4 a simplified side view of a signature resistor element according to a second embodiment;
5 a cross section of the signature resistor element according to 4 ;
6 a simplified side view of a signature resistor element according to a third embodiment;
7 a cross section of the signature resistor element according to 6 ; and
8th a simplified equivalent circuit diagram of an evaluation circuit for monitoring the signature resistance element.
1 to 3 show a simplified side view, an associated cross-section and an associated resistance-length characteristic of a signature-resistance element according to a first embodiment. The signature resistance element in this case has an electrically conductive body which has a random, non-linear resistance-length characteristic RL.
According to 1 the electrically conductive body K may have over its total length L ges a similar electrically conductive material, and particularly an alloy, which is why the electric resistivity ρ of the material for each section length L1, L2, L3 and L4 are equal. Since the resistance R for an electrical conductor results from the formula: R = ρ × L / A, where ρ is the electrical resistivity of the electrical conductor, L is the length of the electrical conductor and A is the cross-sectional area of the electrical conductor can have different cross-sectional areas to realize a non-linear resistance-length characteristic of the electrically conductive body K.
2 shows a simplified cross-sectional view of the electrically conductive body K according to 1 for a first length L1. The electrically conductive body K may, for example, have a cylindrical shape and have a first diameter D1 in its first longitudinal section L1. This results in a first resistor R1 for the first longitudinal section L1. Similarly, the further longitudinal sections L2 to L4 may have further different diameters and thus different cross-sectional areas. The different cross-sectional areas are in accordance with the above-mentioned formula indirectly proportional to the respective partial resistors R2 to R4 and thereby realize the in 3 illustrated non-linear resistance-length characteristic RL.
According to 3 For example, the different slopes in the respective lengths of the RL characteristic can be determined by the different cross-sectional areas, where a small cross-sectional area causes a large slope and a large cross-sectional area causes a small slope. Due to the non-linear distribution of the resistance on the monitoring loop to be monitored or the electrically conductive body K, it is not possible to detect the corresponding partial resistance at a manipulation point. Thus, the backup loop can not be bypassed and opened unnoticed.
A method of manufacturing the signature resistive element according to 1 to 3 is, for example, a wire drawing method in which a cross section of the electric conductive body K is randomly changed by irregular pulling. Similarly, even by an irregular rolling, a resistance wire or the electrically conductive body K can be given a non-linear cross-sectional area distribution over the entire length L tot .
Further, then, an irregular hammering of the drawn or rolled wire or electrically conductive body K can be performed, whereby a non-linear resistance distribution over the length can be further increased.
In the case of irregular drawing or rolling, for example, a multiplicity of length sections Lx are produced, each having constant but mutually different cross-sectional areas. The cross-sectional areas may in this case have a circular area, a rectangular area or other surface shapes. The respective area contents of the length sections Lx and thus the associated slopes in the resistance-length characteristic can therefore be determined by the different outer dimensions of the electrically conductive body K.
It is also possible to use manual or partially manual drawing, rolling or hammering methods in producing the signature resistance element, whereby a randomness of the cross-sectional surface changes can still be increased and the signature resistance element thus bears the "handwriting" of the processor and an unmistakable one-off represents. However, a purely automatic production is possible in which recurring patterns can arise. Namely, if the processing cycles corresponding to the production of the pattern are selected to be sufficiently long and then the required sections are cut by an endless roll, then unique security loop uniques result for this fully automatic production with regard to the distribution of resistance.
Due to the irregular non-linear distribution of the partial resistors Rx per respective length Lx can thus be determined by measuring the length of the fuse wire or -bügels, -kabels, or bolt no inference to the corresponding total resistance R K of the electrically conductive body K or partial resistance of Make Teilabschitts the electrically conductive body K. A manipulation by bridging the fuse loop formed by the electrically conductive body K is therefore much more difficult.
For example, for the electrically conductive body K materials and in particular metal alloys are selected with a very small temperature coefficient α. Although this is not absolutely necessary, it allows a great simplification of an associated evaluation circuit, since temperature-induced resistance fluctuations in the electrically conductive body K are very low and must not be considered or compensated in the evaluation circuit. Preferably, materials which have a temperature coefficient α <200 × 10 -6 / K are used for the electrically conductive body K. In addition to Konstantan TM , which can preferably be used as a material with a low temperature coefficient (α = 10 × 10 -6 / K), other materials such. Manganin ™ (α = 40 × 10 -6 / K) or Nikelin ™ (α = 150 × 10 -6 / K) can be used.
Further, for the electrically conductive body K materials and in particular metal alloys can be used with a high electrical resistivity ρ, since they at relatively small length of the securing loop or the electrically conductive body K have a relatively large resistance and thus large voltage drop, which in turn can be evaluated easily and störunanfälliger in the associated evaluation circuit. Preferably, materials having a specific electrical resistance ρ> 4.0 × 10 -7 Ωm can be used for the electrically conductive body in this regard. As materials with high electrical resistivity ρ, for example, ISAOHM ™ (ρ = 13.2 × 10 -7 Ωm) or ISA-CHROM ™ (ρ ca. 11 × 10 -7 Ωm) can be used.
The electrically conductive body K can, for. B. secure a door of a transport container from unauthorized opening as a backup loop. In this case, the electrically conductive body may preferably be integrated in a safety wire, a safety cable, a securing bracket or a securing bolt. The electrically conductive body may further be surrounded by an electrically insulating material. In particular, the electrically conductive body can be coated by an insulating material (not shown) in such a way that its outer contours are no longer visible and thus an analysis of the resistance distribution is made more difficult.
4 and 5 show a simplified side view and an associated cross section of a signature resistor element according to a second embodiment, wherein like reference numerals describe the same or similar elements as in 1 and 2 Therefore, to avoid repetition of a new description is omitted below. The signature resistance element in this case again has an electrically conductive body K, which has a random, non-linear resistance-length characteristic RL.
According to 4 However, the outer dimensions of the respective lengths Lx are not varied to produce different cross-sectional areas, but different recesses or openings O are formed in the electrically conductive body K, which also vary the cross-sectional areas and thus to the desired random and non-linear resistance length Characteristic RL lead.
5 shows a cross section of the electrically conductive body K according to 4 , According to 5 For example, the electrically conductive body K may be a flat band having a width B and a height H into which the irregular openings O are made.
As a manufacturing method, for example, an irregular punching of the openings O from the belt can be performed automatically and / or manually. The openings O can in this case preferably be formed rectangular and centered in the middle of the band, although other shapes and positions are possible. As in the first embodiment, the cross-sectional areas per length can thereby be varied, resulting in a non-linear resistance-length characteristic for the electrically conductive body K.
As materials in this case, the same materials as in the first embodiment according to 1 be used. Although, according to the second embodiment, it is preferable to use band-shaped electrically conductive bodies K having a cross section according to FIG 5 may in principle also other cross-sectional shapes and in particular cylindrical body, as in 2 shown used.
Moreover, the second embodiment can also be combined with the first embodiment, wherein z. B. an electrically conductive body K according to 4 in addition, as in 1 shown, is changed in its outer dimensions.
6 and 7 show a simplified side view and an associated cross section of a signature resistor element according to a third embodiment, wherein like reference numerals describe the same or similar elements as in the 1 to 5 Therefore, to avoid repetition of a new description is omitted below. The signature resistance element in this case again has an electrically conductive body K, which has a random, non-linear resistance-length characteristic RL.
In the third embodiment, now no longer a same material for the electrically conductive body K but at least two materials with different resistivity ρ is used. As materials in this case, the same materials as in the first embodiment according to 1 be used.
According to 6 For example, the electrically conductive body K may have four different longitudinal sections L1 to L4, which have four different materials and in particular metal alloys. The four different materials consequently each have different specific electrical resistances ρ 1 to ρ 4 , whereby the random, non-linear resistance-length characteristic RL (as in FIG 3 shown) can be realized.
According to 7 For example, a cross section of the electrically conductive body K may be a square represent constant side length a, with other cross-sectional shapes are possible in principle.
Moreover, the third embodiment can also be combined with the first and / or second embodiment in such a way that z. B. an electrically conductive body K according to 6 in addition, as in 1 or 4 is shown, is changed in its outer dimensions and / or recesses O receives, and further for different lengths Lx different materials with associated resistances ρ x are used.
Preferably, according to 6 However, an electrically conductive body K used with a constant cross section and in particular with constant outer dimensions, since in this case an analysis of the security loop and in particular the resistance distribution is particularly difficult.
8th shows a simplified equivalent circuit diagram of an evaluation circuit for monitoring the signature-resistive element, wherein R K denotes the total resistance of the electrically conductive body K of the signature-resistive element.
At the in 8th The evaluation circuit shown is essentially a bridge circuit with a comparator or comparator V, to whose negative input (-) a feedback resistor R V is connected, which is further connected to the output A of the comparator V. In this case, the feedback resistor R V determines the amplification factor of the comparator V and thus the sensitivity of the bridge circuit. Furthermore, at the negative input (-) of the comparator V of the above-described electrically conductive body K is connected to its resistor R K , which is connected at its other end to a supply voltage Ub. At the supply voltage Ub is also a tuning resistor R A is turned on, which is connected at its other end to the positive input (+) of the comparator V. Further, at the positive input (+) of the comparator V, a first bridge resistor R A1 is turned on, which is grounded at its other end. Further, at the negative input (-) of the comparator V, a second bridge resistor R K1 is turned on, which also lies with its other end to ground.
In the bridge circuit according to 8th The following applies: R K / R K1 = R A / R A1 Consequently, even the smallest changes in resistance in the securing loop or the electrically conductive body K can be detected. The output A of the comparator V in this case provides a logic level, which can be further processed, for example, by a (not shown) microcontroller.
Although materials are preferably used for the electrically conductive body which have a particularly low temperature coefficient (such as, for example, Konstantan ™ ), it is also possible, according to the evaluation circuit shown, to use materials and in particular alloys with a poor or high temperature coefficient. Namely, the the "measurement resistance" R K opposing tuning resistor R A of the same material as the electrically conductive body K is made, then the temperature induced resistance changes cancel each other out (if both resistors the same environment and thus are exposed to temperature). Thus, the requirements for the electrically conductive body K can be substantially entschäft respect of its temperature characteristics.
Since even the smallest changes in resistance must be recorded and evaluated, the tuning resistor R A is preferably designed as an adjustable resistor and adjusted when first connecting the backup loop to the evaluation corresponding to the total resistance R K. The bridge circuit is thereby adjusted.

K: elektrisch leitender Körper
R1 bis Rx: Teilwiderstände des el. leitenden Körpers
L1 bis Lx: Längenabschnitte des el. leitenden Körpers
R_K: Gesamtwiderstand des el. leitenden Körpers
L_ges: Gesamtlänge des el. leitenden Körpers
O: Aussparung
H: Höhe des Querschnitts
B: Breite des Querschnitts
a: Seitenlänge des Querschnitts
D: Durchmesser des Querschnitts
Ub: Versorgungsspannung
R_A: Abstimmwiderstand
R_A1: erster Brückenwiderstand
R_K1: zweiter Brückenwiderstand
V: Komparator
R_V: Rückkopplungswiderstand
A: Ausgang

K: electrically conductive body
R1 to Rx: Partial resistances of the el. Conductive body
L1 to Lx: Length sections of the el. Conductive body
R _K: Total resistance of the el. Conductive body
L _ges: Total length of el. Conductive body
O: recess
H: Height of the cross section
B: Width of the cross section
a: Side length of the cross section
D: Diameter of the cross section
ub: supply voltage
R _A: tuning resistor
R _A1: first bridge resistance
R _K1: second bridge resistance
V: comparator
R _V: Feedback resistor
A: output

Claims

Use of a signature resistance element in a security loop, wherein the signature resistance element comprises an electrically conductive body (K) having a predetermined total resistance (R K ) for a predetermined total length (L tot ), the electrically conductive body (K) has a non-linear resistance-length characteristic over its entire length (L tot ).
Use of a signature resistance element according to claim 1, wherein the electrically conductive body (K) over the total length (L ges ) has a non-linear cross-sectional area distribution.
Use of a signature-resistance element according to claim 1 or 2, wherein the electrically conductive body (K) has at least two longitudinal sections (Lx) each having constant and mutually different cross-sectional areas.
Use of a signature-resistance element according to claim 3, wherein the mutually different cross-sectional areas are formed by different outer dimensions and / or by recesses (O).
Use of a signature resistance element according to one of claims 1 to 4, wherein the electrically conductive body (K) over the total length (L ges ) has a same material.
Use of a signature resistive element according to any one of claims 1 to 4, wherein the electrically conductive body (K) over the total length (L ges ) comprises at least two materials having different resistivities.
Use of a signature resistance element according to claim 1, wherein the electrically conductive body (K) over the total length (L ges ) at least two materials having different resistivity and a constant cross-section.
Use of a signature resistor element according to one of claims 1 to 7, wherein the electrically conductive body (K) comprises a material with a temperature coefficient of less than 200 × 10 -6 / K and in particular Konstantan ™ .
Use of a signature resistive element according to any one of claims 1 to 8, wherein the electrically conductive body (K) comprises a material having a resistivity greater than 4.0 x 10 -7 Qm.
Use of a signature resistor element according to any one of claims 1 to 9, wherein the fuse loop is a fuse wire, a fuse cable, a safety clip or a safety pin.