IQS450 204-450-000-001-A1-B24-H05-I0 Signal Conditioner

The IQS450 204-450-000-001-A1-B24-H05-I0 is an industrial-grade eddy current displacement measuring system from Vibro-Meter, specifically designed for applications requiring both large-displacement monitoring and robust long-distance signal transmission. This system integrates core technologies of a 4-mm wide linear measuring range (B24 option) with 2-wire 4-20mA current output, complemented by a standard 5-meter total cable length (H05 option). This combination creates a solution that achieves an excellent balance between measurement range, noise immunity, and installation convenience. It is particularly suitable for demanding industrial scenarios that require monitoring of significant mechanical displacement (such as axial float, thermal expansion) while demanding outstanding electromagnetic interference (EMI) immunity for signal transmission over moderate distances.

Based on the highly reliable eddy current induction principle, the system consists of a precisely matched and factory-calibrated TQ 402/412 series proximity transducer and an IQS 450 signal conditioner. The B24 configuration provides a sensitivity of 1.25 μA/μm, with its linear measuring range extended to 0.3 - 4.3 mm, covering the wide-amplitude displacements typical of most large rotating machinery. Simultaneously, its 2-wire current output mode (operating within the 15.5 - 20.5 mA "live zero" range) inherits all the advantages of the industrial process control 4-20mA standard: insensitivity to line resistance changes, excellent common-mode noise rejection, support for long-distance transmission, and easy implementation of wire-break detection.

The 5-meter cable length is an optimally designed "golden length" for industrial settings. It meets the typical wiring requirements from the sensor to a field junction box or nearby cabinet, while avoiding the cost increase, installation complexity, and potential signal integrity challenges associated with excessively long cables. Designed for standard industrial environments (A1), the system is rugged and durable, capable of stable operation across a wide temperature range from -40°C to +180°C. ATEX and CSA certified explosion-proof versions are also available to meet the requirements of hazardous area applications in sectors such as oil, gas, and chemicals.

Core Value & Unique Advantages:

• Perfect Combination of Wide Range and High-Reliability Current Output: The B24 option simultaneously provides a 4mm wide measurement window and the transmission robustness of current signals, addressing the pain point of signal interference during remote transmission in large-displacement applications.

• High-Resolution "Live Zero" Current Signal: Mapping 4mm of mechanical displacement into a narrow 5mA current window (15.5-20.5mA) achieves a high current resolution of 1.25 μA/μm, making it extremely sensitive to minute changes.

• Optimized 5-Meter System Length: Provides ample installation wiring margin while ensuring optimal system frequency response and signal fidelity, offering high cost-effectiveness.

• Exceptional Environmental Robustness: From the transducer's high-temperature tolerance to the current loop's noise immunity, the system is designed for harsh environments like power plants, refineries, and offshore platforms.

• Simplified System Architecture & Maintenance: The 2-wire system significantly reduces wiring cost and complexity; components are fully interchangeable, lowering spare parts inventory and long-term maintenance costs.

• Seamless Industrial System Integration: The standard 4-20mA current signal can be directly connected to DCS, PLC, SIS, or any monitoring device supporting current input, requiring no additional signal conversion.

2. System Working Principle & Deep Technical Advantages of B24-H05 Configuration

The system operates based on the eddy current effect. The high-frequency signal generated by the IQS 450 conditioner excites the transducer coil, producing an alternating magnetic field. Eddy currents induced in the target metal alter the complex impedance of the coil. A dedicated ASIC circuit inside the conditioner precisely calculates the changes in the real and imaginary parts of this impedance and linearly converts them into a 2-wire DC current.

Unique Technical Value of B24 Mode (1.25 μA/μm, 4mm range):

1. Unification of Wide Range and High Resolution: Across the 4mm wide displacement range, the system maintains a high current resolution of 1.25 μA/μm. This means the system remains highly sensitive to minute changes (such as a few microns of vibration) even when monitoring large-amplitude displacement.

2. Inherent Advantages of Current Signals Manifested in Wide-Range Applications:

• Noise Immunity: When monitoring large equipment, sensor cables often need to run parallel to power cables over long distances. The immunity of current signals to induced voltage noise is of immense value in such scenarios.

• Transmission Distance: For cables of 5 meters or longer, current signals are unaffected by line voltage drop, ensuring the signal received in the control room is identical to that at the sensor.

• Simplicity and Reliability: The 2-wire system reduces the probability of wiring errors and lowers the risk of failures due to connector corrosion.

Synergistic Effect of H05 (5-meter) Cable Length and B24 Current Output:

• Performance Sweet Spot: Five meters is a "performance sweet spot" extensively validated through engineering practice. At this length, the influence of cable distributed parameters (capacitance, inductance) on the system's high-frequency response (20kHz) is minimized, while still meeting the vast majority of intra-machine wiring needs.

• Economy and Convenience: Compared to custom lengths, 5 meters is a standard length, resulting in faster supply and lower cost. During field installation, this length is moderate—not too long to cause coiling difficulties nor too short to be insufficient.

• Cooperation with Safety Barriers: When used in explosion-proof applications or requiring longer transmission distances, the 5-meter cable connects the transducer to a field junction box, which is then connected via ordinary twisted-pair cable to a safety barrier (GSI 124) located in the safe area. This architecture is the most economical and typical.

3. Typical Application Scenarios & Selection Guide

Ideal Application Fields for B24-H05 Configuration:

• Large Steam Turbine-Generator Sets in Power Generation: Axial displacement monitoring of HP/IP and LP casings. Displacement can be several millimeters, and signals need transmission from the noisy turbine deck to the electronics room.

• Centrifugal Compressors in Petrochemical Industry: Radial vibration and axial position monitoring of various stage bearings. Equipment is large, measurement points are scattered, and the site has severe electromagnetic interference (VFDs, large motors).

• Hydro Turbine Main Shaft Runout Monitoring: Large displacement amplitudes, humid installation environment, moderate signal transmission distance.

• Marine Main Propulsion Turbine Reduction Gearboxes: Monitoring position and vibration of gear shafts. Engine room environment is high temperature, high humidity, and high vibration, requiring reliable signal transmission.

• Long-term Condition Monitoring of Large Motors and Pump Trains: Requires a wide range to accommodate potential foundation settlement, misalignment changes, and current signals to ensure long-term stable and reliable data.

Selection Decision Path:

1. Determine Displacement Range: If the expected or maximum displacement to be guarded against may exceed 2mm, or if a very large safety margin (>1mm) is desired during installation, B24 (4mm) should be selected over B22 (2mm).

2. Determine Signal Type:

• If the transmission distance exceeds 10 meters, or there is strong electromagnetic interference on-site, or direct connection to traditional DCS 4-20mA cards is required, priority should be given to B24 current output.

• If the transmission distance is very short (<5 meters), the environment is clean, and the backend is a dedicated vibration monitoring system (typically voltage input), then B23 (voltage output, 4mm) can be considered.

3. Determine Cable Length: Estimate the wiring distance from the transducer installation point to the planned location of the IQS 450 conditioner (or the first termination point). If this distance is between 2 and 8 meters, H05 (5 meters) is usually the optimal choice, providing reasonable margin and optimal performance.

4. Complete Process for Installation, Commissioning & System Integration

1. Core Installation Steps:

• Mechanical Installation & Initial Gap Setting: Strictly adhere to geometrical constraints. Set the initial mechanical gap using feeler gauges. For B24, it is strongly recommended to set the gap between 2.0-3.0 mm (e.g., 2.5mm). This corresponds to an output current of ~18.0mA, positioned in the middle of the linear range, leaving ample room for bi-directional dynamic displacement or unidirectional drift.

• Cable Installation & Fixing: The 5-meter cable should be neatly routed along equipment or cable trays and secured using cable ties or clamps at intervals of 150-200mm, avoiding sagging and vibration. Strictly observe the minimum bending radius.

• Electrical Connection:

1. Form Current Loop: Connect the negative terminal of the -24VDC power supply to the "COM" terminal of the IQS 450, and the positive terminal to the "-24V" terminal.

2. Signal Output: The "OUTPUT" terminal of the IQS 450 is the current output positive, which should be connected to the current input positive of the receiving device (or safety barrier). The input negative of the receiving device then returns to the negative terminal of the power supply, forming a closed loop.

3. Shield Handling: The cable shield should be grounded at a single point only on the control system cabinet side. Absolutely avoid grounding at both the transducer end and cabinet end.

2. Power-Up, Commissioning & Verification:

• Loop Resistance Verification: Before power-up, calculate the total loop resistance Rtotal=Rcable+Rbarrier+RAIRtotal=Rcable+Rbarrier+RAI. Ensure that under the minimum supply voltage, the voltage across the IQS 450 terminals is greater than its required minimum operating voltage (typically >12VDC).

• Static Output Verification: Power on with the machine stationary. Connect a high-precision milliammeter in series in the loop and measure the static current IstaticIstatic. Its value should be between 15.5-20.5mA and roughly match the current estimated from the initial mechanical gap ( I≈15.5+1.25×(Gapmm−0.3)×1000I≈15.5+1.25×(Gapmm−0.3)×1000 ).

• Dynamic Check: After machine startup, observe the gap value and vibration waveform displayed on the monitoring system. Gently tapping the transducer mounting base should produce a corresponding vibration signal response.

3. Integration with Safety Barrier (GSI 124) (for Explosion-Proof or Ultra-Long Distance):

• Role: The GSI 124 is the intrinsic safety barrier between the hazardous area (sensor side) and the safe area (control system side).

• Connection: The output of the IQS 450 is connected to the "hazardous area side" input terminals of the GSI 124. The "safe area side" output of the GSI 124 provides an isolated voltage signal (e.g., -1.6V to -17.6V) proportional to the input current, for acquisition by the control system.

• Note: A GSI 124 model certified for use with the system must be used, and it must be installed and wired strictly according to its instructions.

5. Predictive Maintenance, Troubleshooting & Lifecycle Management

• Regular Maintenance Tasks:

• Visual Inspection: Transducer tightness; cable sheath integrity; connector cleanliness and tightness.

• Electrical Check: Measure the static operating current and compare it with the historical baseline to check for drift.

• Functional Test: Utilize shutdown opportunities to manually move the shaft and check if the monitoring system display changes continuously.

• System Health Diagnostics (via Current Value Judgment):

• Below 4mA: Open circuit, power loss, or severe IQS 450 failure.

• Stable below 15.5mA: Transducer gap is much greater than 4.3mm or target is missing.

• Stable above 20.5mA: Transducer gap is less than 0.3mm, transducer is contacting the target, or metal debris is adhering to the tip.

• Current within normal range but no fluctuation: Possible transducer damage (coil open but conditioner outputs a fixed bias) or target not rotating (for vibration measurement).

• Excessive current fluctuation (noise): Poor shield grounding, strong electromagnetic interference, extremely poor target surface condition.

• Spare Parts Strategy: Since TQ transducers and IQS 450 conditioners are fully interchangeable, stocking key spare parts is recommended. Replacement does not require on-site calibration; only confirmation of correct initial gap setting is needed.