K-type compensating wires can effectively compensate for the voltage loss of thermocouple signals during long-distance transmission, reduce measurement errors caused by line factors, and make the measurement results closer to the true temperature values, providing accurate temperature data support for industrial production and other applications. It can improve the physical and mechanical properties of thermocouple temperature measurement circuits. Compared to directly using expensive long-distance specialized thermocouple cables, using K-type compensating wires to connect thermocouples and measuring devices is a more economical choice, greatly reducing the cost of measurement circuits while ensuring measurement effectiveness.

Compensation wires or cables insulated and sheathed with polyvinyl chloride generally have excellent moisture-proof, wear-resistant, and flame-retardant properties; The products with high-temperature resistant fluoroplastic insulation and sheath adopt continuous extrusion process, which is more resistant to high temperature, cold, acid, alkali, oil and water, non delayed combustion, anti-aging and other characteristics. The product quality is higher than the national standard and has a long service life. It usually has good flexibility and bending performance, is easy to install and wire, and can adapt to various complex working environments and installation conditions.

Measurement steps for K-type compensating wire:

1. Appearance inspection

-Integrity of insulation layer: Check for any damage, cracks, or signs of aging on the insulation outer layer of the compensating wire. If the insulation is poor, it may cause short circuits or signal interference, affecting measurement accuracy. For example, compensating wires that have been used for a long time may experience insulation layer wear at bends.

-Clarity of identification: Confirm whether the model identification (such as "K" type) and positive and negative pole markings on the wire are clear and distinguishable. This is the foundation for proper connection and use. If the labeling is unclear, it can easily cause wiring errors.

-Observation of wire core material: For the exposed part of the wire core, check whether its metal color and texture are normal, and whether there are any abnormal phenomena such as oxidation and discoloration, in order to preliminarily determine whether the wire core material meets the requirements.

2. Conductivity test

-Measurement of resistance range with a multimeter: Use the resistance range of a digital multimeter to measure the resistance value between the positive and negative terminals of the compensating wire. Under normal circumstances, the resistance value should be within a reasonable range and relatively stable within a certain length range. If the resistance is too high or infinite, there may be an open circuit problem; If the resistance is too small or even close to zero, there may be a short circuit situation. Different specifications of K-type compensating wires have corresponding standard resistance ranges for reference.

-Continuity check: Gradually press and bend along the length of the wire, while observing changes in the multimeter reading, to check for intermittent open circuit points. This method can help detect hidden faults caused by internal wire fatigue, virtual soldering, and other reasons.

3. Thermoelectric characteristic verification

-Set up a testing environment: Prepare a high-precision standard temperature source, such as a constant temperature bath or oil bath, that can accurately set and maintain specific temperature points. Connect the K-type thermocouple to the compensation wire to be tested in the prescribed manner and place it in a standard temperature source.

-Data collection and comparison: At different temperature points, read the thermoelectric potential values generated by this combination and compare them with theoretical values or other known good compensation wires of the same type under the same conditions. For example, conducting tests at typical temperature points such as 0 ℃, 50 ℃, and 100 ℃, recording the actual measured millivolts, and analyzing deviations. If the deviation exceeds the allowable range, it indicates that the thermoelectric characteristics of the compensating wire are not qualified.

-Stability assessment: Maintain a stable temperature point for a period of time, continuously monitor the thermoelectric potential output, and observe its fluctuations. High quality compensation wires should be able to maintain stable thermoelectric potential output with minimal fluctuations; If the fluctuation is severe, it indicates that its performance is unstable and may be greatly affected by environmental factors or have quality problems.

4. Polarity verification

-Connect the display instrument for observation: Connect the compensation wire correctly to the matching display instrument (such as temperature transmitter, temperature controller, etc.), then turn on the power and check whether the temperature value displayed on the instrument changes as expected. When heating up the hot end, if the instrument displays an increase in temperature, it indicates that the polarity connection is correct; On the contrary, if the temperature drops or fluctuates abnormally, it is likely that the polarity is reversed.

-Exchange method confirmation: You can also try exchanging the positive and negative poles before connecting the instrument and observing the temperature display changes again. If the opposite trend of change is displayed before and after the exchange, it further confirms the original polarity judgment result.