1Portable dielectric constant testerOperating Standards: Standardized Process from Laboratory to Industrial Site

Equipment preparation and calibration

Environmental adaptability inspection: Industrial sites need to confirm the environmental temperature (0 ℃~40 ℃), humidity (<80%), and power stability (220V ± 22V, 50Hz ± 2.5Hz) to avoid high temperature, high humidity, or electromagnetic interference environments. The laboratory needs to control the temperature and humidity within the required range of the instrument (such as 25 ℃± 1 ℃, 50% RH ± 5%).

Calibration process:

Laboratory: Use standard dielectric constant sheets (such as polytetrafluoroethylene with ε=2.1) for two-point calibration (zero position and full-scale), and calibrate once a month.

Industrial site: Adopting a fast calibration mode, using portable standard samples (such as ceramic plates with known ε) for single point calibration to shorten downtime.

Fixture adaptation: Select fixtures based on the material type (such as parallel plates, coaxial probes) to ensure that the sample size matches (such as solid disk diameter of 15-50mm, thickness of 2 ± 0.5mm).

Test operation steps

Sample preparation:

Solid material: Cut to the specified size, clean the surface with anhydrous ethanol to remove defects such as cracks and bubbles.

Liquid material: Vacuum degassing treatment (-0.1MPa standing for 30 minutes), slowly pour along the inner wall of the cylindrical electrode to avoid the mixing of bubbles.

Powder material: Press into circular pieces using a tablet press under a pressure of 20MPa, measure 3 pieces and take the average value.

Test mode selection:

Laboratory: Prioritize the use of high-frequency resonance method (25kHz-160MHz), combined with automatic frequency locking and resonance point search technology, to improve measurement accuracy (± 1.5pF).

Industrial site: Adopting broadband testing mode (4MHz-3GHz or 200MHz-14GHz) to meet the requirements of fast detection, but attention should be paid to the influence of frequency selection on material polarization mechanism.

Data recording: Record the testing date, sample information, environmental parameters (temperature and humidity, air pressure), testing frequency, and results for easy traceability of error sources.

Safety Specifications

Laboratory: instruments are placed horizontally, away from corrosive gases and direct sunlight; Operators should wear protective gloves and glasses to avoid high-voltage electric shock.

Industrial site: Set up warning signs and isolate high-voltage testing areas; Use independent grounding poles (grounding resistance ≤ 1 Ω) to prevent static electricity accumulation; In case of emergency, immediately turn off the main power supply.

2、 On site interference elimination: full scenario response from environment to electromagnetic interference

Environmental interference suppression

Temperature and humidity fluctuations:

Phenomenon: The measured value fluctuates by more than 5% (such as changes in the ε value of ceramic materials).

Solution: Move the instrument into a constant temperature and humidity chamber (25 ℃± 1 ℃, 50% RH ± 5%), let the sample stand for 2 hours, and then test it.

Mechanical vibration:

Phenomenon: Uneven compaction of powder materials leads to scattered results.

Solution: Use a tablet press to uniformly press the pressure (20MPa), shorten the testing time (<5 minutes), and reduce the impact of environmental vibration.

Electromagnetic interference (EMI) protection

Power frequency interference:

Phenomenon: The measured value is affected by 50Hz/100Hz harmonic interference, with significant fluctuations.

Solution:

Use double-layer shielded cables (with the inner shielding layer grounded and the outer shielding layer floating) to shorten the electrode leads to within 30cm.

Connect a 100nF capacitor (high-frequency bypass) and a 100 μ H inductor (low-frequency choke) in parallel at the signal input end to form an LC filtering network.

Space electromagnetic field interference:

Phenomenon: Strong electromagnetic fields are generated by nearby motors and frequency converters, resulting in measurement errors.

Solution:

Place the instrument in a metal shielding box (shielding effectiveness ≥ 60dB), or at least 2 meters away from the interference source.

Using the phase difference method (square wave shaping method) to measure tan δ and reduce the impact of electromagnetic interference on phase detection.

Quick troubleshooting of equipment malfunctions

Fuse blown:

Phenomenon: The device cannot start after a power surge.

Solution: Use a multimeter to measure the continuity of the fuse and replace it with a fuse of the same specification (distinguish between slow melting and fast melting types).

Heating element malfunction:

Phenomenon: Abnormal temperature sensor display (deviation>5 ℃).

Solution: Use a multimeter to measure the resistance of the heating element in the resistance range (normally tens to hundreds of ohms), recalibrate or replace the sensor.

Poor electrode contact:

Phenomenon: The measured value is low or fluctuates greatly.

Solution: Clean the surface oxide layer of the electrode, wrap the electrode lead with copper foil to form Faraday shielding, and reduce contact resistance.

IIIPortable dielectric constant testerComparison of operational differences between industrial sites and laboratories

dimension	Laboratory operations	Industrial site operation
Calibration frequency	Once a month, use standard samples for two-point calibration	Once a day, quick single point calibration
test mode	High frequency resonance method (25kHz-160MHz), accuracy priority	Broadband testing (4MHz-3GHz), speed priority
environmental control	Constant temperature and humidity chamber, with strict and stable temperature and humidity	Natural environment, interference suppression through shielding boxes and filters
sample preparation	Precise cutting, cleaning, and degassing to ensure no defects	Quickly suppress and tilt, allowing for a certain range of error
safety measures	Protective gloves, glasses, regular grounding	Warning signs, independent grounding poles, emergency stop buttons, and strengthened electromagnetic protection