Description
Bently Nevada 3500/72M (176449‑08) Recip Rod Position Monitor
Product Overview
176449‑08 is the main monitor board for 3500/72M Reciprocating Rod‑Position Monitor, dedicated for reciprocating compressors within the 3500 machinery‑protection system. It accepts proximity probe signals, performs rod‑position, rod‑drop, hyper‑compressor measurements, detects packing wear, rod fracture risk, cross‑head abnormal clearance. Fully complies with API 618 reciprocating‑compressor standard. Cannot operate standalone; must pair with matching I/O assembly and install in the same rack slot.
176449‑08
Technical Specifications
| Item | Parameter |
|---|---|
| Part Number | 176449‑08 (3500/72M main board) |
| Matching I/O | 140734‑08 (non‑barrier internal‑termination, safe‑area); 135490‑01 (IS‑barrier internal‑termination, hazardous‑area) |
| Channels | 4 channels, configured in pairs (Ch1‑2 / Ch3‑4) |
| Sensor Input | Proximity transducers (eddy‑current probes) |
| Measurement functions | Rod Position, Rod Drop, Hyper‑compressor mode |
| Power Consumption | 5.8 W typical, powered by rack backplane |
| Operating Temperature | ‑30 ℃ ~ +65 ℃ (rack); Storage:‑40 ℃ ~ +85 ℃ |
| Form Factor | Single‑slot plug‑in for 3500 rack |
| Weight | Approx. 0.91 kg |
| Compliance | API 618, API 670; supports hot‑swap |
| Front‑panel LED | OK, Bypass, TX/RX status indicators |
| Configuration | 3500 Rack Configuration Software; Alert / Danger programmable setpoints |
Key Features
- Four‑channel pair‑wise configuration: Channels work in pairs; different measurement modes can be set for each pair. Supports rod‑position, rod‑drop, hyper‑compressor high‑pressure reciprocating‑compressor measurement.
- Rod‑drop protection: Monitors piston‑rod downward displacement; early warning for packing failure, rod loosening and fracture risk, critical safety protection for reciprocating compressors.
- Complete transducer‑loop supervision: Detects probe open‑circuit, short‑circuit, gap‑voltage fault diagnostics.
- Dedicated reciprocating‑compressor monitor: Normally deployed together with 3500/70M (impulse‑velocity) and 3500/77M (cylinder‑pressure) to build full reciprocating‑compressor monitoring solution.
- Predictive‑maintenance data output: Sends position waveform & trending data to System 1, DCS, SCADA via rack backplane.
- Hot‑swap capable: Online module replacement following official maintenance procedure.
I/O assembly comparison for 3500/72M
| Part Number | Barrier | Termination | Application |
|---|---|---|---|
| 140734‑08 | Non‑IS | Internal | Safe‑area sensor installation |
| 135490‑01 | Built‑in IS‑barrier | Internal | ATEX / Class I Div 2 hazardous‑area field sensors |
Important: Do not mix‑use I/O assemblies of 3500/70M / 3500/72M. Hardware is incompatible.
Typical Applications & Scenarios
Main Applications
- Real‑time monitoring of reciprocating‑compressor piston‑rod position and rod‑drop.
- Detect packing wear, cross‑head clearance abnormal, rod looseness and hidden fracture risk.
- Provide Alert / Danger alarm and trip interlock signal for machinery protection; deliver position data for predictive‑maintenance analysis.
Industry Scenarios
- Oil & gas: natural‑gas compressor stations, refineries, offshore‑platform reciprocating compressors.
- Petrochemical: hydrogen compressors, hyper‑compressors, process‑gas reciprocating units complying with API 618.
176449‑08
Supporting & Matching Components
- Mandatory paired I/O assembly
- Safe‑area: 140734‑08 non‑barrier internal‑termination I/O
- Hazardous‑area: 135490‑01 IS‑barrier internal‑termination I/O
- Host rack: 3500/05 instrument rack
- Rack power supply: 3500/15 power‑supply modules
- Field sensors: Proximity probe systems for rod‑position measurement; for hazardous‑area, adopt IS‑certified probes & cables.
- Auxiliary modules
- 3500/32M / 3500/33 relay modules: hardware alarm & trip contact output
- 3500/92 / 3500/77M gateway: upload monitoring data and alarms
- Configuration software: 3500 Rack Configuration Software
Related Reference Part Numbers
- 140734‑08: Non‑barrier I/O for 3500/72M
- 135490‑01: IS‑barrier I/O for 3500/72M
- 3500/72M‑01‑00: Complete assembly (176449‑08 +140734‑08 safe‑area)
- 3500/72M‑01‑02: Complete assembly (176449‑08 +135490‑01 hazardous‑area IS‑barrier)
- 3500/70M: Recip impulse‑velocity monitor
- 3500/77M: Recip cylinder‑pressure monitor (P‑V curve diagnosis)
Installation & Maintenance Notes
- 176449‑08 main board must mount behind matching I/O in same rack slot; barrier‑type & non‑barrier‑type I/O cannot be mixed for one monitor set.
- For hazardous‑area applications, only use 135490‑01, together with intrinsically‑safe certified probes & cables, comply with local hazardous‑installation codes.
- Separate sensor signal wiring from high‑voltage power cables to reduce noise interference.
- After installation, verify channel health status, sensor fault‑detection and alarm logic in 3500 configuration software.
- Hot‑swap replacement must strictly follow Bently Nevada official service manual.
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