DE102009060893A1 - Transmitter e.g. thermoelectric temperature transmitter, for signal conversion of thermoelectric measured variables with electronic transmitter module, has good-heat conducting and/or warm-spreading layer attached under and/or in substrate - Google Patents

Abstract

The transmitter has two soldering or welded joints (3) electrically attached to thermal wires (1, 2) on a substrate (10). A temperature sensor (5) is connected between the soldering or welded joints that include combined materials. Two material components are made of thermal material of the thermal wires and a copper alloy. The soldering or welded joints are connected with an input amplifier module (7). A good-heat conducting and/or warm-spreading layer are attached under and/or in the substrate. A boron nitride-layer is applied over the soldering or welded joints of the wires. An independent claim is also included for a method for signal conversion of thermoelectric measured variables with an electronic transmitter module in a transmitter.

Description

The invention relates to a measuring transducer and a method for signal conversion of thermoelectric measured quantities with electronic transmitter modules.

The invention is suitable for use in thermoelectric temperature transmitters for signal conversion. In this case, a signal conversion with reference junction correction and further corrections for electrical errors takes place.

It is known, by means of so-called thermometer head transmitter, d. H. In the thermometer connection head mountable transmitter modules, and by means of so-called snap rail transmitter, d. H. Transmitter modules that can be installed in an electronics cabinet to convert thermoelectric voltage signals from thermocouple pairs into standardized signals. Normally, standard output signals are used as current signals in the range from 4 mA to 20 mA as well as voltage signals in the range from 0 V to 10 V. Furthermore, digital signal sequences in a variety of forms, e.g. For example, CEN bus, CAN bus, MOD bus, PWM signal, ZAK wire signal sequences, etc. are used.

The thermoelectric temperature transmitters must make a reference junction correction during signal conversion. To Bernhard: Technical Temperature Measurement, Springerverlag Berlin / Heidelberg, 2004 , several equivalent methods are known for this purpose. In the simplest case, the temperature at the reference junction is determined via an additional measuring channel, and a mathematical correction is made with this reference junction temperature value.

Temperature measurement with temperature transmitters may become inaccurate if the signal characteristic between input and output signal is incorrect. It also becomes inaccurate if the reference junction temperature is erroneously or not accurately determined at the reference junction and / or there is a temperature gradient between the two thermoelectric wire legs at the reference junction. The latter is especially the case when the reference junction is placed near the temperature measuring point and heat in the two different thermo legs is also conducted differently to the reference junction, because this wire-bound heat transfer noticeably enters into the heat balance at the reference junction. Furthermore, the known thermoelectric transducers do not allow corrections for the non-electrical installation and dynamic measurement errors.

The invention has for its object to provide a method and an apparatus of the type mentioned, with which an effective signal evaluation is made possible for thermocouples, which also performs a correction of static-thermal and dynamic measurement errors in addition to the conversion of the thermoelectric signal conversion to normalized signals.

The object is achieved with a method having the features specified in the claim 1, and with a device having the features specified in the claim 6, solved.

Advantageous embodiments are specified in the subclaims.

The device is characterized in that it can be made very compact. The design of the reference junction achieves high measurement accuracy with low production costs. This can be further improved by correcting the reference junction temperature by means of a correction program for detecting the built-in measurement error and thus achieving a low measurement uncertainty with minimum effort.

The transducer and method also allow for accurate temperature determination for applications where the site and cold junction are located close to each other and where there are high temperatures at the site which directly affect the cold junction.

Furthermore, the use of a predictive evaluation method for increasing the measuring dynamics of the temperature sensor is advantageous, the method being based on different time percentage characteristic values (eg t ₆₃ ), such as during heating (eg t _{63 up} ) and cooling (eg . t _63ab ) are present in the high measuring range and when using fast-response temperature sensors.

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

In the accompanying drawings show:

1 a schematic representation of the arrangement and

2 a measuring arrangement with mineral-insulated jacket thermoelectric line.

In the 1 The device shown is on a substrate 10 assembled. On the input side are the thermocouple wires 1 and 2 on connection pads 4 by soldering or welding 3 attached. For example, there is the first thermal wire 1 NiSi and the second thermo wire 2 made of NiCrSil. Between these Soldering or welding points 3 there is a temperature sensor 5 , The connection pads 5 and the temperature sensor 5 are over the copper interconnects 6 with an input amplifier module 7 connected. The input amplifier module 7 can use more electronic modules 8th be followed for signal conditioning. At the exit 9 the processed signal is removed.

2 explains an embodiment in which on the substrate 10 the components temperature sensor 5 , Copper tracks 6 , Input amplifier module 7 and modules 8th for signal conditioning in a tubular metal frame 15 are arranged. The metal frame 15 is solid with the mineral-insulated, metal-protected jacket thermocouple 11 connected, taking on the jacket thermolysis 11 a process connection 13 , which in the example shown consists of collar and compression screw, is attached.

The thermocouple wires 1 and 2 the jacket thermolysis 11 and their measuring point 12 are by means of soldering or welding pads 4 and soldering or welding 3 with the input amplifier module 7 electrically connected. About the cable connection 14 that with the outgoing cable connection points 9 of the substrate 10 is connected, the processed transmitter signals are passed to the outside. To reduce the effects of vibration and strong heat conduction can in the neck tube area 16 the jacket thermolysis 11 coiled or annular.

LIST OF REFERENCE NUMBERS

1

first thermal wire

2

second thermal wire

3

Soldering or welding point

4

pads

5

temperature sensor

6

Copper interconnects

7

Input amplifier module

8th

further modules for signal conditioning

9

outgoing cable connection points

10

substratum

11

metal-protected mineral-insulated cladding thermolines

12

Measuring point, Thermoperle

13

process connection

14

cable

15

metal Mount

16

Neck tube part

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 non-patent literature

• Bernhard: Technical Temperature Measurement, Springerverlag Berlin / Heidelberg, 2004 [0004]

Claims (8)

Transducer for signal conversion of thermoelectric quantities with electronic transmitter modules, characterized in that - on a substrate ( 10 ) at least two soldering or welding points ( 3 ) for the electrical connection of thermo wires ( 1 . 2 ), - between the soldering or welding points ( 3 ) a temperature sensor ( 5 ), - the soldering or welding points ( 3 ) contain combined materials, wherein a material component consists respectively of the thermal material of the thermo-wire and a second material component consists of a copper alloy and - the soldering or welding points ( 3 ) with an input amplifier module ( 7 ) are connected. Transmitter according to Claim 1, characterized in that the input amplifier module ( 7 ) with further modules ( 8th ) is connected for signal conditioning. Transmitter according to claim 1 or 2, characterized in that below and / or in the substrate ( 10 ) a gutwärmeleitende and / or heat-spreading layer is attached. Transmitter according to one of the preceding claims, characterized in that over the soldering or welding points ( 3 ) of the thermo wires ( 1 . 2 ) a BN layer is applied. Transmitter according to one of the preceding claims, characterized in that the input amplifier module ( 7 ) and the other modules ( 8th ) are combined for signal conditioning to a common ASic module. Method for signal conversion of thermoelectric measured quantities with electronic transmitter modules in a transmitter, in which thermoelectric voltage signals of connected thermocouples are converted into standard signals, taking into account the reference junction temperature, characterized in that - at the reference junction between the thermo wires ( 1 . 2 ) a temperature value is determined, - with this temperature value a signal value converted in the transmitter is corrected, - whereby this correction takes place taking into account installation errors of the temperature sensor design. A method according to claim 6, characterized in that the installation error for the measuring arrangement used from measurement series and / or calculations according to the VDI guideline 3511 is determined. A method for thermoelectric signal conversion, in particular according to claim 6 or 7, characterized in that a rapid signal conversion by a predictive sampling and evaluation process by both Zeitprozentkennwerte from heating and Zeitprozentkennwerte from cooling of the temperature sensor are taken into account.

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