TQ 402 & TQ 412 / EA 402 / IQS 452 Proximity Transducer System Technical Guide: Configuration, Installation, Operation, Debugging, and Maintenance
Author: Site Editor Publish Time: 2025-11-11 Origin: Site
Chapter 1: Introduction – System Overview
TQ 402 & TQ 412 / EA 402 / IQS 452 Proximity Transducer System responsible for accurately capturing the relative shaft vibration and axial position of critical rotating machinery (such as steam turbines, gas turbines, compressors, and pumps), providing the most fundamental and core data for equipment protection and predictive maintenance. This guide aims to provide engineers and technicians with a complete technical reference covering the entire lifecycle from system selection and configuration to long-term operation and maintenance.
Core System Components:
TQ 402 / TQ 412 Proximity Transducer: The core sensing element of the system, operating on the eddy current principle.
TQ 402: Standard Mount version, fully threaded body, suitable for direct installation inside machinery.
TQ 412: Reverse Mount version, with an integral locking nut, designed specifically for installation through probe adapters from outside the machine.
EA 402 Extension Cable: Connects the transducer to the signal conditioner, ensuring the total system length meets strict electrical requirements.
IQS 452 Signal Conditioner: The "signal brain" of the system, providing high-frequency excitation power to the transducer and demodulating, amplifying, and outputting a signal proportional to the gap. Its sub-versions include:
IQS 452 Ver. 0XX/1XX: Provides a 4 mm linear range, with voltage output (4 mV/μm) and current output (1.25 μA/μm) respectively.
IQS 452 Ver. 2XX/3XX: Provides a 2 mm linear range, with voltage output (8 mV/μm) and current output (2.5 μA/μm) respectively.
Key Certifications and Compatibility:
Explosion-Proof Certification: System components are available in intrinsically safe (Ex i) versions certified by ATEX (LCIE 02 ATEX 6086 X) and CSA (1514309), suitable for use in potentially explosive atmospheres.
System Integration: The standard signals output by this system can be seamlessly integrated into mainstream machinery protection systems.
Documentation Basis: All content in this guide is extracted, integrated, and compiled from the official document MANUAL - Vibration System Field Equipment (Seq # 36400), ensuring accuracy and authority.
Chapter 2: Configuration – System Design and Engineering Preparation
Correct system configuration is a prerequisite for ensuring its performance and measurement accuracy, primarily involving transducer selection, system length determination, and signal conditioner settings.
2.1 Transducer and Cable Configuration
Transducer Selection:
Based on the measurement target (vibration/position) and spatial constraints, choose TQ 402 (Standard Mount) or TQ 412 (Reverse Mount).
Based on the expected shaft displacement range, determine the required linear measuring range (2 mm or 4 mm), which will determine the matching IQS 452 version.
Total System Length (TSL) Determination:
Golden Rule: The total cable length from the transducer tip to the signal conditioner input (Integral Cable + Extension Cable) must be strictly 5 meters or 10 meters. The system's electrical characteristics are optimized for this length. Any deviation will lead to loss of calibration and performance degradation.
Length Calculation and Ordering: Based on the installation distance, select the appropriate length of the integral cable (e.g., 1m, 5m) and the EA 402 extension cable (e.g., 4m, 9m), ensuring the sum is 5m or 10m.
Select appropriate protection for the cables based on the field environment:
2.2 Signal Conditioner Configuration
Output Mode Selection:
3-Wire Voltage Output (Versions 0XX, 2XX): Low output impedance, good compatibility, maximum transmission distance of 200 meters.
2-Wire Current Output (Versions 1XX, 3XX): Strong anti-interference capability, maximum transmission distance of 1000 meters, but must be used with an isolator like the GSI 123.
Sensitivity and Range Matching:
Ensure the selected IQS 452's sensitivity (4 or 8 mV/μm) and range (2 or 4 mm) match the TQ 402/412 transducer and measurement requirements.
Power Requirements:
The IQS 452 requires a -20 VDC to -32 VDC power supply from the machinery protection frame.
2.3 Target Material and System Characterization
Standard Target Material: The system is calibrated for use with VCL 140 Steel (1.7225).
Non-Standard Materials: If the target material is a different alloy (e.g., stainless steel, aluminum), the system's sensitivity and linear range will change. In this case, system characterization must be performed before installation to determine the actual voltage-distance curve and the true linear measuring range and sensitivity through experimentation.
Chapter 3: Installation – Mechanical and Electrical Implementation
Correct installation is the physical foundation for ensuring long-term stable operation and data accuracy of the system.
3.1 Mechanical Installation
Location and Environment:
Ensure the installation area is clean, dry, and free of corrosive gases.
Keep away from strong vibration sources and heat sources.
Transducer Mounting Constraints (Must be strictly observed):
Free Space: Minimum distances must be maintained in front of, to the sides of, and behind the transducer head (TQ 402/412 full range: Front 34mm, Sides 13mm, Rear 46mm).
Distance to Mounting Support: Minimum distance from the transducer head to the mounting support is 13mm.
Distance Between Transducers: Minimum distance between two side-by-side transducers is 51mm.
Distance to Shaft Shoulder/End: Minimum distance to shaft shoulder for radial measurement is 9mm; minimum distance to shaft end for axial measurement is 14mm.
Mounting Methods:
Inside Machine Housing: Use mounting brackets with tapped or clearance holes. For clearance holes, two locknuts are required. Apply LOCTITE 241 adhesive to the threads to prevent loosening.
Through Machine Housing: Use PA 113 or PA 103 probe adapters (for TQ 412 only). This allows for transducer adjustment and replacement from outside.
Mechanical Adjustment of Initial Gap:
Vibration Measurement: Set at the center of the linear range.
Position Measurement: Set towards the end opposite the direction of expected movement.
Concept: The distance between the transducer tip and the target surface when the machine is at rest.
Setting Principle:
Setting Method: Use a feeler gauge to set the gap precisely. Safety Margin: The minimum gap must not be less than 0.4mm (for 4 mV/μm systems).
3.2 Electrical Wiring
Cable Installation:
Inside the machine, secure cables every 100 to 200 mm using cable clamps.
Strictly observe the minimum bending radius: 40 mm for FEP coaxial cable, 50 mm for cable with BOA armour.
Never shorten or lengthen cables. Excess cable should be coiled with a diameter not less than the minimum bending radius and secured.
Connection and Protection:
Mate the connector of the transducer's integral cable with the EA 402 extension cable connector and immediately place it inside a JB 118 Junction Box or the protective housing of the PA 113 for IP65 protection.
Critical: The metal shell of the connector must not contact grounded metal parts to prevent ground loop interference.
Cable Feedthrough:
Use an SG 102 Cable Feedthrough, wrapping the threads with Teflon tape to ensure a seal (IP68).
Signal Conditioner Mounting:
Mount the IQS 452 on the insulating plate inside an ABA 15X Industrial Housing to prevent ground loops.
System Wiring:
3-Wire: Use K 309/K 310 cable, connect to "OUT", "COM", "-24V".
2-Wire: Use K 209/K 210 cable, connect to "OUT", "-24V", and connect to a GSI 123 isolator.
Connect the extension cable to the IQS 452 input.
Connect the transmission cable according to the output mode:
Shielding: The transmission cable shield must be grounded at one point only: the machinery protection system end (inside the cabinet). The transducer and conditioner ends must remain floating.
Chapter 4: Operation – System Runtime and Monitoring
Once the system is powered up and operational, daily operation and status monitoring are key to ensuring production safety.
4.1 Status Monitoring
IQS 452 Signal Conditioner Status: Monitor its "OK", "Alert", "Fault" status via the card status lights of the machinery protection system or accompanying software (e.g., ToolboxST).
Output Signal Monitoring: Monitor the dynamic value of the transducer signal (DC component represents average gap, AC component represents vibration) and waveform in real-time on the control system's HMI or diagnostic pages.
4.2 Data Communication
Integration with Control System: The analog voltage/current signal output by the IQS 452 is directly connected to the analog input card of the machinery protection system (e.g., Bently Nevada 3500/42M).
Alarm and Trip: When vibration or position values exceed preset alarm and danger thresholds, the system generates alarms and triggers protective actions.
Data Logging and Analysis: Signals can be sent to a historical database for trend analysis and fault diagnosis.
4.3 Basic Operations
Online Monitoring: Observe vibration overall value, gap voltage, waveform, and spectrum in real-time through the system software without stopping the machine.
Precautions:
Avoid using power tools or other strong electromagnetic interference equipment near the transducer.
Ensure the target surface is clean, free of oil, rust, or magnetic deposits, as these affect measurement accuracy.
Chapter 5: Debugging – System Verification and Functional Testing
Debugging is the necessary process to verify that the system is installed correctly, configured accurately, and functions as designed.
5.1 Pre-Power Up Checks
Double-check that all mechanical mounting constraints are met.
Check that all cable connections are secure and shielding is correctly grounded (single point).
Check power supply polarity.
5.2 Loop Testing and Verification
Gap-Voltage Characteristic Verification:
Using a feeler gauge, set the gap to several known points within the linear range (e.g., min, mid, max).
Measure the corresponding output voltage or current on the machinery protection system side or directly at the IQS 452 output terminals.
Compare the measured values with the theoretical curve from the data sheet or the curve obtained from characterization; the error should be within an acceptable range.
Dynamic Function Test:
For vibration measurement, gently tap the shaft (if safe to do so) and observe if the vibration signal responds accordingly.
For position measurement, slowly move the shaft and observe the linear change in the gap voltage.
5.3 System Integration Testing
Alarm and Trip Function Test:
Simulate high vibration or position exceedance signals to verify that the control system correctly generates alarm and danger (trip) signals.
Check that alarm displays on the HMI are correct.
Channel Redundancy Test (if applicable): If the system is configured with redundant transducers and channels, simulate a primary channel fault and verify that the system seamlessly switches to the backup channel.
Chapter 6: Maintenance – Preventive and Corrective Actions
Systematic maintenance is the cornerstone for ensuring long-term system reliability.
6.1 Routine Maintenance
Periodic Inspections:
Visual Inspection: Check transducers, cables, and protections for physical damage (scratches, dents, burns).
Mechanical Inspection: Confirm transducers are securely mounted and not loose. Check the condition of cable clamps.
Electrical Check: Periodically perform loop tests (see 5.2), recording data to observe long-term drift trends.
Connector Inspection: Check the integrity of seals on JB 118 or protective housings, and look for signs of moisture or corrosion inside.
Cleaning: Keep the transducer head and target surface clean. Carefully clean the probe face using isopropyl alcohol and non-metallic tools.
6.2 Diagnostics and Troubleshooting
Symptom
Potential Cause
Troubleshooting Steps
No Signal or Very Low Signal
1. Power not connected or reverse polarity. 2. Cable open or short circuit. 3. Poor connector contact. 4. IQS 452 or transducer failure.
1. Check cabinet power and voltage at IQS 452 terminals. 2. Check cable continuity and insulation. 3. Re-seat all connectors. 4. Swap conditioner or transducer to test.
Noisy/Unstable Signal
1. Improper shield handling (ground loop). 2. Cable run close to power lines. 3. Connector shell accidentally grounded. 4. Magnetic spots or severe runout on target surface.
1. Verify shield is single-point grounded only at the cabinet. 2. Re-route cable away from noise sources. 3. Check connector insulation. 4. Inspect and treat target surface.
Signal Drift
1. Normal drift due to temperature change. 2. Gradual deterioration of transducer or cable. 3. Mechanical loosening, changing transducer gap.
1. Compare with temperature drift coefficient in datasheet. 2. Perform system characterization check. 3. Check transducer mounting tightness.
Output does not match gap relationship
1. Non-standard target material without characterization. 2. Incorrect Total System Length. 3. Mounting constraints violated.
1. Perform system characterization for the actual target material. 2. Verify total cable length is 5m or 10m. 3. Review and satisfy all mounting constraints.
6.3 Component Replacement
Replacing a Transducer:
Shut down the machine and perform Lockout-Tagout (LOTO).
Disconnect the cables after noting their connection points.
Remove the old transducer.
Install the new transducer and strictly follow the steps in Chapter 3 to re-adjust the mechanical initial gap.
Reconnect the cables.
Perform Loop Testing and Verification (Section 5.2) to ensure the new transducer system is functioning correctly.
Replacing a Signal Conditioner (IQS 452):
Prepare a new IQS 452 of the same model and version.
Power down and replace the conditioner.
After power-up, since system parameters are stored on the control system side, no additional configuration is usually needed. However, output verification should be performed.
6.4 Spare Parts Management
It is recommended to stock critical spare parts, such as transducers, extension cables, and signal conditioners.
Record the model numbers, version numbers, and serial numbers of spare parts to ensure compatibility with the existing system.
