TQ402,TQ412, EA402 and IQS900 Proximity Measurement
Author: Site Editor Publish Time: 2025-08-14 Origin: Site
The TQ402/TQ412, EA402, and IQS900 proximity measurement system operates based on the eddy-current principle for non-contact measurement. Its core operational workflow is as follows: the IQS900 signal conditioner generates a high-frequency signal that drives the TQ4xx series probe. The coil in the probe head consequently produces an alternating electromagnetic field. When this field approaches a metal target surface (such as the shaft of rotating machinery), it induces eddy currents in the target material.
These eddy currents react back on the probe's electromagnetic field, altering the coil's impedance. The change in impedance has a functional relationship with the gap between the probe and the target surface. The high-performance modulation/demodulation circuit within the IQS900 precisely detects this minute change, demodulates and amplifies it, and ultimately outputs a high-precision voltage or current signal that is linearly proportional to the gap distance.
The core value offered by this principle lies in:
Absolute Reliability: Non-contact measurement avoids wear, providing an virtually unlimited service life.
Extreme Precision and Response Speed: The system frequency response reaches DC to 20 kHz, enabling it to not only monitor slowly changing axial positions but also accurately capture high-speed shaft vibrations, providing critical data for predictive maintenance.
Environmental Adaptability: The probe features a stainless steel housing encapsulated with high-temperature epoxy resin and a tip made of Torlon (polyamide-imide). It can operate long-term in harsh environments from -40°C to +180°C, and even withstand short-term exposure to temperatures as high as 220°C.
TQ402/TQ412 Proximity Probes The TQ402 is the standard model, while the TQ412 is designed for reverse mounting to accommodate different mechanical installation space requirements. The probe employs a fully sealed stainless steel structure, with an internally precision-optimized coil ensuring a concentrated and stable electromagnetic field. Its integrated coaxial cable is sheathed in FEP (fluorinated ethylene propylene) material, offering excellent resistance to chemical corrosion, high temperatures, and low permeability. The probe tail is standardly equipped with a self-locking miniature coaxial connector, ensuring a secure and reliable connection. Users can select metric or imperial threads, as well as different body lengths and cable lengths, according to their needs.
EA402 Extension Cable To install the probe in hard-to-reach locations, the EA402 extension cable becomes an indispensable part of the system. It utilizes the exact same high-performance coaxial structure as the probe's integrated cable, ensuring minimal signal attenuation and distortion over long-distance transmission. The system supports three total system lengths (TSL): 1 meter, 5 meters, and 10 meters. Through a unique "electrical trimming" technique, the performance of the entire measurement chain and probe interchangeability are optimized even when combining cables of different lengths.
IQS900 Intelligent Signal Conditioner The IQS900 is the "brain" of the system, representing the advanced level of current signal conditioning technology. Compared to its predecessor, the IQS450, it achieves significant enhancements across multiple dimensions:
Provides two output modes: voltage (-1.6V ~ -17.6V) or current (-15.5mA ~ -20.5mA). Its low output impedance design allows for better matching with third-party isolation barriers or safety barriers.
Offers an optional built-in self-test (BIST) function capable of continuously monitoring the health status of the sensor, cabling, and its own circuitry. Upon detecting a fault, it immediately provides remote alarm via output signals deviating from the normal range, greatly enhancing system maintainability and safety.
Possesses the capability, "by design," to achieve SIL 2 (IEC 61508) / PL Cat 1 (ISO 13849) levels, easily meeting the requirements for Safety Instrumented Function (SIF) applications.
Features improved common-mode rejection ratio and electromagnetic compatibility (EMC), ensuring stable performance in complex industrial electromagnetic environments.
Provides raw signal (RAW) output and test (TEST) input interfaces, facilitating in-depth diagnostics and system calibration by field engineers without interrupting operation.
Removable screw-terminal connectors and an optional DIN-rail mounting adapter (MA130) make installation, wiring, and maintenance exceptionally straightforward.
