CN117191208A - Thermocouple thermoelectric voltage detection method and device - Google Patents
Thermocouple thermoelectric voltage detection method and device Download PDFInfo
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Abstract
The invention relates to the technical field of thermocouple thermoelectric voltage measurement, in particular to a thermocouple thermoelectric voltage detection method and device. According to the thermocouple thermoelectric voltage detection method, the irregular periodic alternating voltage component in the detection channel of the data acquisition unit is introduced to the ground through the capacitor element of the external circuit, meanwhile, direct grounding of the thermocouple thermoelectric voltage detection is avoided, the phenomenon of fluctuation of measured data caused by channel faults can be effectively eliminated, the effective service life of the data acquisition unit is prolonged, the whole data acquisition unit is prevented from being replaced due to a small number of channel faults, and accordingly overhaul and maintenance costs are saved.
Description
Technical Field
The invention relates to the technical field of thermocouple thermoelectric voltage measurement, in particular to a thermocouple thermoelectric voltage detection method and device.
Background
The wall temperature of a boiler tube of a power plant is usually acquired by a front-end data acquisition unit, and then sent to a DCS system operator station for display through MODBUS communication. The data collector is located natural environment temperature is high, dust is many, and the channel fault often appears and causes the measured data fluctuation, discovers through on-the-spot inspection: an irregular periodic alternating current voltage component is usually arranged in the fault channel, and the alternating current voltage component is larger than the thermoelectric voltage measured by the thermocouple, so that the interference can be caused to the thermoelectric voltage detected by the data acquisition device channel, and the data fluctuation is caused.
Disclosure of Invention
Therefore, the invention aims to solve the technical problem that the alternating voltage component in the prior art interferes with the thermoelectric voltage detected by the data acquisition device channel to cause data fluctuation.
In order to solve the technical problems, the invention provides a thermocouple thermoelectric voltage detection method, which comprises the following steps:
measuring thermoelectric potential of the thermocouple by using a data acquisition device to obtain a measurement result;
detecting whether the thermocouple is normal or not when the measurement result shows data fluctuation;
when the thermocouple detects that the thermocouple is normal, the alternating current voltage value in the measuring channel of the data acquisition device is measured;
selecting a capacitive element meeting a preset condition according to the alternating voltage value;
eliminating alternating voltage in a measuring channel of the data acquisition device by using the capacitance element;
and re-measuring the thermoelectric potential of the thermocouple by using a data collector after the alternating voltage in the measuring channel is eliminated.
Preferably, the measuring the thermoelectric couple thermoelectric voltage by the data collector, the obtaining the measurement result includes:
a data acquisition unit is used for acquiring thermocouple temperature signals;
transmitting the temperature signal to a DCS system operator station;
and recording IDAS temperature measuring points of a DCS operator interface to obtain the measuring result.
Preferably, when sending the temperature signal to the DCS system operator station comprises:
and sending the temperature signal to a DCS system operator station through MODBUS communication.
Preferably, when the thermocouple detects a wire break or misalignment, the thermocouple is replaced with a spare core.
Preferably, the measuring the ac voltage value in the measuring channel of the data collector includes:
and measuring the alternating voltage value in the channel by using an alternating voltage mV gear measuring data collector of the universal meter.
Preferably, the preset condition is that the conductive capability of the capacitor element can timely derive the ac voltage on the premise of ensuring that the capacitor element is not broken down by the ac voltage.
Preferably, said eliminating the ac voltage in the data collector measurement channel with the capacitive element includes:
one end of the first capacitor is connected to the positive end of the thermocouple compensation cable, and the other end of the first capacitor is grounded;
one end of the second capacitor is connected with the negative end of the thermocouple compensation cable, and the other end of the second capacitor is grounded.
The invention also provides a thermocouple thermoelectric voltage detection device, which comprises:
the measuring channel of the data acquisition device is connected with the thermocouple compensation cable through the terminal strip and is used for acquiring thermocouple temperature signals;
one end of the first capacitor is connected with the positive end of the thermocouple compensation cable, and the other end of the first capacitor is grounded and is used for eliminating alternating voltage in a measuring channel of the data acquisition device;
and one end of the second capacitor is connected with the negative end of the thermocouple compensation cable, and the other end of the second capacitor is grounded and is used for eliminating the alternating voltage in the measuring channel of the data acquisition device.
Preferably, the first capacitor and the second capacitor can timely derive the ac voltage on the premise of ensuring that the first capacitor and the second capacitor are not broken down by the ac voltage.
Preferably, the internal circuit of the measurement channel of the data collector comprises a multiplexer, a programmable amplifier and an analog-to-digital converter.
Compared with the prior art, the technical scheme of the invention has the following advantages:
according to the thermocouple thermoelectric voltage detection method, the irregular periodic alternating voltage component in the detection channel of the data acquisition unit is introduced to the ground through the capacitor element of the external circuit, meanwhile, direct grounding of the thermocouple thermoelectric voltage detection is avoided, the phenomenon of fluctuation of measured data caused by channel faults can be effectively eliminated, the effective service life of the data acquisition unit is prolonged, the whole data acquisition unit is prevented from being replaced due to a small number of channel faults, and accordingly overhaul and maintenance costs are saved.
Drawings
In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings, in which:
FIG. 1 is a flow chart of a thermocouple thermoelectric voltage detection method according to the present invention;
fig. 2 is a block diagram of a thermoelectric couple thermoelectric voltage detection device according to an embodiment of the present invention.
Detailed Description
The invention is characterized in that the invention provides a thermocouple thermoelectric voltage detection method and a device, which effectively introduce an abnormal alternating voltage component in a fault channel of a data acquisition unit into the ground through the isolation AC function of a capacitor, simultaneously avoid direct grounding of thermocouple thermoelectric voltage measurement, effectively eliminate the phenomenon of fluctuation of measured data caused by channel faults, prolong the effective service life of the data acquisition unit, and avoid the replacement of the whole data acquisition unit due to a small number of channel faults, thereby saving the overhaul and maintenance costs.
In order to better understand the aspects of the present invention, the present invention will be described in further detail with reference to the accompanying drawings and detailed description. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, fig. 1 is a flowchart of a thermocouple thermoelectric voltage detection method according to the present invention; the specific operation steps are as follows:
s101, measuring thermoelectric potential of a thermocouple by using a data acquisition device to obtain a measurement result;
s102, detecting whether a thermocouple is normal or not when the measurement result shows data fluctuation;
s103, when the thermocouple detects that the thermocouple is normal, measuring an alternating current voltage value in a measuring channel of the data collector;
s104, selecting a capacitor element meeting preset conditions according to the alternating voltage value;
s105, eliminating alternating voltage in a measuring channel of the data collector by using the capacitive element;
s106, re-measuring the thermoelectric potential of the thermocouple by using a data collector after the AC voltage in the measuring channel is eliminated.
According to the thermocouple thermoelectric voltage detection method, the irregular periodic alternating voltage component in the detection channel of the data acquisition unit is introduced to the ground through the capacitor element of the external circuit, meanwhile, direct grounding of the thermocouple thermoelectric voltage detection is avoided, the phenomenon of fluctuation of measured data caused by channel faults can be effectively eliminated, the effective service life of the data acquisition unit is prolonged, the whole data acquisition unit is prevented from being replaced due to a small number of channel faults, and accordingly overhaul and maintenance costs are saved.
Based on the above embodiments, the present embodiment describes step S101 in detail:
the method for measuring the thermoelectric potential of the thermocouple by using the data collector comprises the following steps:
a data acquisition unit is used for acquiring thermocouple temperature signals;
the temperature signal is sent to a DCS system operator station through MODBUS communication;
and recording IDAS temperature measuring points of a DCS operator interface to obtain the measuring result.
Based on the above embodiments, the present embodiment describes step S102 in detail:
when the thermocouple detects a wire break or misalignment, the thermocouple is replaced with a spare core.
Based on the above embodiments, the present embodiment describes in detail step S103:
the measuring of the alternating voltage value in the measuring channel of the data collector comprises the following steps:
and measuring the alternating voltage value in the channel by using an alternating voltage mV gear measuring data collector of the universal meter.
Based on the above embodiments, the present embodiment describes in detail step S104:
the preset condition is that the conductive capacity of the capacitive element can timely lead out the alternating voltage on the premise of ensuring that the capacitive element is not broken down by the alternating voltage.
Based on the above embodiments, the present embodiment describes in detail step S105:
the eliminating the alternating voltage in the measuring channel of the data collector by using the capacitive element comprises:
one end of the first capacitor is connected to the positive end of the thermocouple compensation cable, and the other end of the first capacitor is grounded;
one end of the second capacitor is connected with the negative end of the thermocouple compensation cable, and the other end of the second capacitor is grounded.
Referring to fig. 2, fig. 2 is a block diagram illustrating a thermoelectric voltage detection device of a thermocouple according to an embodiment of the present invention; the specific apparatus may include:
the measuring channel of the data acquisition device is connected with the thermocouple compensation cable through the terminal strip and is used for acquiring thermocouple temperature signals; the internal loop of the measuring channel of the data acquisition device comprises a multiplexer, a programmable amplifier and an analog-to-digital converter.
One end of the first capacitor is connected with the positive end of the thermocouple compensation cable, and the other end of the first capacitor is grounded and is used for eliminating alternating voltage in a measuring channel of the data acquisition device;
and one end of the second capacitor is connected with the negative end of the thermocouple compensation cable, and the other end of the second capacitor is grounded and is used for eliminating the alternating voltage in the measuring channel of the data acquisition device. The first capacitor and the second capacitor can timely lead out the alternating voltage on the premise of ensuring that the first capacitor and the second capacitor are not broken down by the alternating voltage.
Based on the above examples, this example provides a specific implementation, specifically as follows:
1) And checking and recording IDAS temperature measuring points with data fluctuation on a DCS operator interface, and determining the number and channel number of the on-site data acquisition unit.
2) Finding out the corresponding data collector and fault channel, firstly checking whether the thermocouple is normal, and if the thermocouple is broken or misaligned, replacing the spare core. If the thermocouple detects normal, a multimeter is used for 'AC voltage mV gear'
The channel is checked for the presence of an alternating voltage component and its magnitude is measured. ( On-site measurement results: the alternating-current mV gear can jump between hundreds of mV to infinity )
3) Two capacitive elements of appropriate capacitance and voltage class are selected according to the magnitude of the ac voltage detected in the data collector fault channel. ( The principle of selecting a capacitor element is as follows: ensure that the capacitor is not broken down by abnormal alternating voltage, and the conductivity meets the requirement of timely leading out abnormal alternating component )
4) One end of a selected capacitor is connected into the H end (namely the positive end of the thermocouple compensation cable) of the measuring channel terminal block of the data acquisition unit, and the other end is grounded nearby. One end of the other selected capacitor is connected to the terminal strip of the measuring channel of the data acquisition unit
The L end (i.e. the thermocouple compensation cable negative end) and the other end is grounded nearby.
5) The thermocouple was properly inserted into the measurement channel.
6) And measuring whether the alternating voltage component is effectively eliminated or not on the channel, and checking whether the thermoelectric potential energy of the thermocouple is correctly detected or not.
7) And observing and confirming whether the original fault channel data fluctuation is eliminated or not at a DCS operator station interface.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations and modifications of the present invention will be apparent to those of ordinary skill in the art in light of the foregoing description. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.
Claims (10)
1. A method for detecting thermoelectric potential of a thermocouple, comprising:
measuring thermoelectric potential of the thermocouple by using a data acquisition device to obtain a measurement result;
detecting whether the thermocouple is normal or not when the measurement result shows data fluctuation;
when the thermocouple detects that the thermocouple is normal, the alternating current voltage value in the measuring channel of the data acquisition device is measured;
selecting a capacitive element meeting a preset condition according to the alternating voltage value;
eliminating alternating voltage in a measuring channel of the data acquisition device by using the capacitance element;
and re-measuring the thermoelectric potential of the thermocouple by using a data collector after the alternating voltage in the measuring channel is eliminated.
2. The method of claim 1, wherein measuring the thermocouple thermoelectric voltage with the data collector, the measuring result comprising:
a data acquisition unit is used for acquiring thermocouple temperature signals;
transmitting the temperature signal to a DCS system operator station;
and recording IDAS temperature measuring points of a DCS operator interface to obtain the measuring result.
3. The thermocouple thermoelectric voltage detection method according to claim 2, wherein when sending the temperature signal to a DCS system operator station comprises:
and sending the temperature signal to a DCS system operator station through MODBUS communication.
4. The thermocouple thermoelectric force detection method according to claim 1, wherein when the thermocouple detects a wire break or an misalignment, the thermocouple is replaced with a spare core.
5. The method of claim 1, wherein measuring the ac voltage value in the measurement channel of the data collector comprises:
and measuring the alternating voltage value in the channel by using an alternating voltage mV gear measuring data collector of the universal meter.
6. The method according to claim 1, wherein the preset condition is that the conduction capability of the capacitor element can timely lead out the ac voltage on the premise of ensuring that the capacitor element is not broken down by the ac voltage.
7. The method of claim 1, wherein said removing the ac voltage in the data collector measurement channel with the capacitive element comprises:
one end of the first capacitor is connected to the positive end of the thermocouple compensation cable, and the other end of the first capacitor is grounded;
one end of the second capacitor is connected with the negative end of the thermocouple compensation cable, and the other end of the second capacitor is grounded.
8. A thermocouple thermoelectric voltage detection device, comprising:
the measuring channel of the data acquisition device is connected with the thermocouple compensation cable through the terminal strip and is used for acquiring thermocouple temperature signals;
one end of the first capacitor is connected with the positive end of the thermocouple compensation cable, and the other end of the first capacitor is grounded and is used for eliminating alternating voltage in a measuring channel of the data acquisition device;
and one end of the second capacitor is connected with the negative end of the thermocouple compensation cable, and the other end of the second capacitor is grounded and is used for eliminating the alternating voltage in the measuring channel of the data acquisition device.
9. The thermocouple thermoelectric voltage detection device according to claim 8, wherein the first capacitor and the second capacitor can timely conduct the ac voltage without breakdown by the ac voltage.
10. The thermocouple thermoelectric voltage detection device according to claim 8 wherein the internal circuit of the data collector measurement channel comprises a multiplexer, a programmable amplifier and an analog to digital converter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311063705.3A CN117191208A (en) | 2023-08-22 | 2023-08-22 | Thermocouple thermoelectric voltage detection method and device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311063705.3A CN117191208A (en) | 2023-08-22 | 2023-08-22 | Thermocouple thermoelectric voltage detection method and device |
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| CN117191208A true CN117191208A (en) | 2023-12-08 |
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| CN202311063705.3A Pending CN117191208A (en) | 2023-08-22 | 2023-08-22 | Thermocouple thermoelectric voltage detection method and device |
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| CN (1) | CN117191208A (en) |
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- 2023-08-22 CN CN202311063705.3A patent/CN117191208A/en active Pending
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