Key Technical Specifications
- Model set: PR6426/010-140 probe + CON021/916-200 signal conditioner
- Measurement principle: Eddy current (non-contact)
- Probe linear range: 0 to 2 mm
- Linearity error: ≤ ±1% full scale
- Probe length: 140 mm, M10×1 threaded mounting
- Probe operating temperature: -40 °C to +120 °C
- Converter supply: 24 VDC ±10%
- Converter operating temperature: -20 °C to +60 °C
- Frequency response: DC to 10 kHz (-3dB)
- Converter housing: IP20, DIN rail mount
- Probe rating: IP67 sealed stainless steel body
- Connector type: Lemo locking connector between probe and converter
Product Introduction
This Emerson EPRO assembly combines a proximity probe and matched signal converter. It captures shaft vibration and displacement for turbines, compressors and large rotating equipment. The matched probe-converter pair maintains calibrated sensitivity across the full linear gap. A 10 kHz bandwidth tracks fast rotor dynamic events; the Lemo connector locks to prevent intermittent signal loss from machine vibration. (The converter has two front-panel LED indicators for power and cable fault.)
Installation & Configuration Guide
Preparation (10 min) Lock and tag out rotating machinery. Verify 24 VDC supply at DIN rail terminal. Gather feeler gauges, torque wrench, and ESD wrist strap. Confirm target shaft has clean, uniform metallic surface.
Removal (5–10 min) Take photos of Lemo connection and converter wiring. Unplug Lemo connector. Loosen probe locknut and unscrew probe from mounting bracket. Do not pull on the armored cable.
Installation (10 min) Thread PR6426 probe into bracket. Set nominal air gap using feeler gauges, then tighten locknut to specified torque. Connect armored cable Lemo plug fully until it clicks. Mount CON021 onto DIN rail.
Power-On & Test (10 min) Apply 24 VDC to CON021. Confirm power LED illuminates. Measure analog output to validate mid-gap reading. Run cable fault check via converter diagnostics before returning machine to service.
Troubleshooting Quick Reference
| Symptom | Likely Cause | Verification Action |
|---|---|---|
| No signal, converter power LED off | Missing or out-of-range 24 VDC supply | Measure terminal voltage; confirm 21.6–26.4 VDC |
| Fixed saturated reading | Probe touching shaft or gap outside linear range | Retract probe, recheck air gap with feeler gauge |
| Noisy, fluctuating signal | Poor target surface or ungrounded shield | Inspect shaft surface; verify single-point shield grounding |
| Cable fault LED active | Damaged armored cable or loose Lemo connector | Unplug, inspect Lemo pins; check cable for crushing |
| Steady offset drift | Temperature change at probe tip | Allow thermal stabilization, recheck mid-gap value |
Dimensions, Mounting & Wiring Notes
- Probe H×W×D: 140 mm length, M10 thread body; Converter: 90 mm × 72 mm × 30 mm
- Mounting: Probe via M10 threaded bracket; CON021 clips onto standard 35 mm DIN rail
- Terminal notes: Use single-point grounding for the cable shield. Avoid sharp bends on armored cable; minimum bend radius per EPRO manual. Do not route probe cable alongside high-current power cables. The Lemo connector must fully engage; partial seating creates intermittent faults.
FAQ
Q: Is Emerson still manufacturing the PR6426/010-140 + CON021/916-200 assembly new? A: No, OEM production has ended. Available stock consists of refurbished, fully tested assemblies. Verify with OEM datasheet for your monitor system compatibility.
Q: What minimum power supply margin should I maintain for the CON021 converter? A: Keep a 20% voltage margin. A nominal 24 VDC source must stay above 19.2 VDC under load.
Q: I’m replacing this set on a steam turbine. Can I swap the probe while the machine runs? A: No. Rotating shaft presents mechanical hazard. Lock out, confirm zero rotation before adjusting or removing the proximity probe.
Q: What physical damage signs should I inspect before accepting a used EPRO probe assembly? A: Look for crushed armored cable, cracked probe tip ceramic, scratched target sensing face, or corrosion on Lemo pins. A burnt odor from the converter board indicates internal circuit damage.
Q: Can I pair a PR6426 probe with a different CON021 suffix variant? A: Not recommended. Each CON021 suffix is calibrated for a specific probe length and cable capacitance. Mismatched suffix creates incorrect sensitivity.
Q: Can this probe work on a shaft with rough rust or scale? A: No. Surface irregularities create false displacement readings. The target area must be clean, machined metal free of coating and rust.
Q: What happens if the probe tip contacts the rotating shaft? A: Ceramic tip will chip or shatter. The converter enters cable-fault state, and vibration readings become invalid.
