DE202015002110U1 - Arrangement for, in particular high-resistance, resistance measurement on textile products - Google Patents

Abstract

Arrangement for, in particular high-resistance, resistance measurement on textile products and for wireless measured value transmission by means of UHF RFID tag, wherein the RFID tag comprises a sensor interface and a voltage output fed by the UHF field, characterized in that the voltage output with an adjustable, high-constant low-voltage reference in Connection is to produce an output voltage which is in the range of the voltage window of the sensor interface, further provided for this purpose at the output of the low voltage reference, a voltage divider and reference resistor, which is connected to the sensor interface, wherein the reference resistor adjusts to the resistance to be measured equivalent voltage ,

Description

The invention relates to an arrangement for, in particular, high-resistance, resistance measurement on textile products and for wireless transmission of measured values by means of UHF RFID tags, the RFID tag comprising a sensor interface and a voltage output fed by the UHF field, according to the preamble of claim 1.

From the DE 10 2013 004 025 A1 a device for detecting, storing and reading the moisture, in particular of plant substrates is already known.

This device comprises a passive transponder together with RFID and sensor electronics as well as an antenna. Furthermore, a lancet-like spit is present, in which interconnects connect the RFID electronics via a sensor interface with at least provided in a lower level of the spit contact electrodes for impedance measurement. The contact electrodes are provided on the outer surface of the aforementioned spit facing the plant substrate.

In the operation and evaluation after EP 1 584 930 B1 There is a sensor which, depending on the insect infestation, has an altered resistance, which is determined by measurement. A circuit arrangement present there has a constant-voltage source that can be stimulated by a transponder, which generates a current flow through a measuring resistor when stimulated by the transponder. Above the resistor a constant voltage drops. At a circuit node, a potential is detected, which adjusts depending on current flows. When the potential reaches a predetermined threshold or when passing through the threshold, an output signal change, which correlates with the actual measured variable.

Sensors for contactless evaluation of certain physical states are known. Such devices are based on the so-called RFID technology and are operated in different frequency ranges. By means of the RFID technology, on the one hand, a voltage supply of the sensor components can be realized and, moreover, the desired wireless transmission of the determined measurement data can take place.

RFID circuits with integrated sensor interfaces usually have the possibility of being able to measure voltages in a certain range, a so-called voltage window.

However, it has been found that in many cases both the voltage measurement window is inadequate, but also existing reference voltages have unsuitable values for a large number of measurement tasks.

From the above, it is therefore an object of the invention to provide a further developed arrangement for, in particular high-resistance, resistance measurement on textile products and wireless transmission of measured values by means of UHF RFID tag, the advantages of UHF RFID technology such as higher range, shorter reading cycles and high to be transmitted data rates can be used to the full extent, without the disadvantages of the lower energy transfer from the electromagnetic field limit the intended applications.

The object of the invention is achieved with the feature combination according to claim 1, wherein the dependent claims comprise at least expedient refinements and developments.

It is therefore assumed that an arrangement for, in particular high-resistance, resistance measurement on textile products and wireless transmission of measured values by means of UHF RFID tag, wherein the RFID tag comprises a sensor interface and a voltage output fed by the UHF field.

For textile materials, it may be z. B. garments, in particular protective clothing act, z. As such protective clothing that helps prevent electrostatic charge to avoid damage to electronic assemblies during their manufacture or assembly.

According to the invention, the voltage output of the UHF RFID tag is connected to an adjustable, high-constant low-voltage reference in order to generate an output voltage which lies in the region of the voltage window of the sensor interface. Furthermore, for this purpose, at the output of the low-voltage reference, a voltage divider together with reference resistor is provided, which is connected to the sensor interface, wherein at the reference resistor an equivalent voltage to be measured resistance sets, which is then processed via the UHF RFID tag and transmitted by classical air interface.

In a preferred embodiment, the low-voltage reference is designed as a circuit arrangement of temperature-compensated differential amplifiers.

The working range of the UHF RFID tag is essentially between 860 and 960 MHz.

The arrangement according to the invention is mounted on a wiring carrier and can be fixed in this form to the respective textile product.

The wiring carrier further comprises means for contacting the textile product.

An RFID tag which can be adhered in this respect and which can be contacted electrically can have an adhesive layer for a reversible connection to the textile. The electrical contact with the textile can be done via penetrating into the textile, spike-like contacting agent.

With the arrangement according to the invention, it is possible to measure low voltages accurately to functional properties of technical textiles, eg. B. to determine their resistances with high accuracy.

The invention will be explained in more detail below with reference to embodiments and figures.

Hereby show:

1 a block diagram of the device according to the invention;

2 a circuit detailing;

3 an exemplary internal circuit of the low voltage reference and

4 exemplary embodiments of a UHF RFID tag on a wiring carrier with spike-like contacting means.

1 shows a block diagram of the inventive arrangement, which with a test object 1 , in particular a technical textile, which has a very high electrical resistance.

The actual device includes an RFID tag 2 which operates in the UHF range in an externally applied electromagnetic field.

In this regard, the tag contains a frequency matched antenna device 3 and has a sensor input 4 ,

The antenna device 3 serves both the wireless transmission of measured by the sensor device and processed by the day measured values as well as the voltage supply of the tag.

Between measuring object 1 and sensor input 4 is a measurement circuit 4a provided, the adaptation between the object to be measured 1 and the specifics of the sensor input 4 serves.

This is how the measuring circuit can work 4a a voltage divider circuit and a reference resistor. In this regard, be on the 2 directed.

Inside the RFID sensor 2 is an A / D converter 6 integrated for the purpose of digitizing analogue measurement signals. Via an internal communication unit 7 the detected and digitized measurement signals and measurement results are converted into communication signals and an antenna device 3 wirelessly, ie via an air interface, to a reading device 9 , which also has an antenna, transmitted.

In the RFID sensor 2 There is a unit for generating a variable depending on the transmitted power operating voltage 8th , This converts the energy of the electromagnetic field received via the antenna device into an operating voltage in order to operate a reference voltage circuit 5 sure.

The operating voltage unit 8th acts according to the invention with the reference voltage circuit 5 together. This reference voltage circuit 5 Provides the constant output voltage required for the respective measurement task and the DUT, thus providing appropriate signal processing related to the signal window of the sensor 4 can be done.

The reference voltage circuit 5 is thus supplied via the energy which is radiated wirelessly from the reader with antenna and received and provided by the antenna of the UHF-RFID.

The reading and evaluation device 9 triggers the RFID tag in this sense 2 , ie supplies it with energy, so that after signal processing, the measurement result via the air interface 3 to the RFID reader 9 arrives. The RFID reader 9 is with an external host 10 can be coupled, which is used to evaluate the received measurement data and to control the RFID sensor. control means 11 serve the operation of the RFID reader or after activating the control of the RFID sensor or tags 2 , evaluation 12 include algorithms for converting received measurements or for data processing.

The 2 shows an exemplary circuit embodiment, wherein the RFID tag is provided for operation in the UHF frequency range.

For example, a circuit SL900A is used.

At each input ANT and V _{SSA there} is one antenna pole 3 connected. In addition, at least two sensor inputs EXT2 and V _SS (ground connection) are provided which form a voltage window. Thus, voltages in the range of 0.26 to 1.22 V can be measured, ie processed, at these inputs.

The outputs EXT2 and V _SS are connected to measuring contacts CONT1 and CONT2, which contact the block thus formed as a whole with the object to be measured.

As a measuring object here, for example, a Kitteltextil is provided, the electrostatic Abschirmfähigkeit to be determined by a resistance determination.

As measuring contacts CONT1 and CONT2, for example, needle-like measuring contacts or snap button-like contacts come into consideration.

The circuit 2 Also includes an output V _POS , which is connected through a resistor RB to a low voltage reference 5 connected.

As a low voltage reference 5 For example, an LT6650 circuit is used.

At output OUT5 of the low voltage reference 5 is a constant voltage, which is tuned to the measuring range, on.

The entire assembly is located on a wiring carrier 14 , including the measuring circuit 4a ,

The measuring circuit 4a consists of a voltage divider, comprising the resistors RF and RG and the reference resistor RV, The voltage divider circuit of RF, RV and RG is adapted in their dimensions to the expected properties of the DUT.

Summarized at this point, the circuit owns 2 , designed as a UHF RFID chip, the sensor inputs 7 and 8th for external applications that can measure voltages in the range of 0.26 to 1.22V. The circuit 2 represents from the over the antenna 3 received a maximum voltage of 3.4 V electromagnetic field received. This voltage can be loaded with a maximum current of 200 μA. For reproducible voltage measurements or the determination of high-resistance resistors, however, a constant voltage in the range of 1.2 V to 1.5 V is required.

With the help of the application of the circuit according to the invention 5 and its internal 400 mV reference source with a tolerance of 0.5% succeeds in providing the required low-voltage reference. The output voltage of the circuit 5 can be set between 0.4 V and almost the input voltage. For the feedback circuit a current of 4 to 8 μA and for the input applied to the input FB, a current of 10 nA is assumed. Thus, the total current load is within the specifications of the device 2 ,

By dimensioning the resistors RF, RG and RV, the optimum measurement range for the measurement on the voltage divider thus formed can be in the range of 0.26 to 1.22 V, ie the relevant window of the circuit 2 be set.

In order to be able to fully exploit the voltage window of 0.26 V to 1.22 V, it is expedient to generate a constant voltage> 1.22 V. The voltage divider could in one embodiment of the invention z. For example, the values RF = 487 kOhm and RG = 196 kOhm can be used to provide a constant voltage of 1.4V. The measurable resistance range can be adjusted by means of RV. For a measuring range of z. For example, 4 MOhm to 122 MOhm RV should be interpreted as 18 MOhm.

The 3 shows an exemplary internal structure of the low voltage reference 5 , In this regard, temperature-compensated differential amplifiers are used which, unlike conventional Z-diode based circuits, provide a sufficiently low voltage reference around 400 mV.

The 4 illustrates an exemplary use of a UHF RFID tag for resistance measurement.

The in the 4 top illustration shows a technical textile 15 with a day arranged on it 16 , The technical textile 15 For example, a gown, ie, a conductive fabric, is used to prevent electrostatic charges on integrated circuits or similar components.

The day 16 gets on the smock 15 fixed and activated by an initialization and interrogation device, not shown in the figure. They too 1 and 2 explained components perform a measurement of the electrical properties of the textile 15 by, wherein the measured values are transmitted via the RFID interface to an evaluation unit.

The middle representation (side view) as well as the lower representation after 4 show an expedient for such a measurement process embodiment of the RFID tag 16 with appropriate contact. The contacting of the tag 16 can be via spike-shaped contacts 17 respectively. The spike-shaped contacts are formed so that they penetrate into the fabric of the textile and there existing supply lines of z. B. contact measuring electrodes.

To the day 16 on the textile material 15 To secure, can be a reversibly releasable adhesive layer 18 be provided.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102013004025 A1 [0002]
• EP 1584930 B1 [0004]

Claims (6)

Arrangement for, in particular high-resistance, resistance measurement on textile products and for wireless measured value transmission by means of UHF RFID tag, wherein the RFID tag comprises a sensor interface and a voltage output fed by the UHF field, characterized in that the voltage output with an adjustable, high-constant low-voltage reference in Connection is to produce an output voltage which is in the range of the voltage window of the sensor interface, further provided for this purpose at the output of the low voltage reference, a voltage divider and reference resistor, which is connected to the sensor interface, wherein the reference resistor adjusts to the resistance to be measured equivalent voltage , Arrangement according to claim 1, characterized in that the low-voltage reference is designed as a circuit arrangement of temperature-compensated differential amplifiers. An arrangement according to claims 1 or 2, characterized in that the operating range of the UHF RFID tag is between substantially 860 to 960 MHz. Arrangement according to one of the preceding claims, characterized in that it can be fixed on a wiring carrier located on the respective textile product. Arrangement according to claim 4, characterized in that the wiring support comprises means for contacting the textile product. Arrangement according to claim 4 or 5, characterized in that as the wiring support an inlay, a printed circuit board, an integrated circuit, a hybrid circuit or the like means is used.

Images