3500/72-01-00 Bently Nevada Recip Rod Position Monitor

Introduction to the 3500/72-01-00 Recip Rod Position Monitor

When reciprocating compressor performance degrades, the 3500/72-01-00 from Bently Nevada provides the critical measurements you need. This four-channel monitor accepts input from proximity transducers, conditions the signal, and delivers dynamic and static position data. It compares these conditioned signals against user-programmable alarms, helping you protect valuable machinery.

Part of the Bently Nevada 3500 series, the 3500/72-01-00 is engineered for continuous monitoring. It meets API 618 requirements for reciprocating compressors, making it a reliable choice for industrial applications.

Key Features and Technical Specifications

• Accepts from 1 to 4 proximity probe signals per channel.
• Input impedance is 10 kΩ.
• Nominal scale factors: 0.79 mV/µm (20 mV/mil), 3.94 mV/µm (100 mV/mil), or 7.87 mV/µm (200 mV/mil) for rod position.
• Power consumption: 7.7 watts nominal.
• Front buffered outputs: one coaxial connector per channel, short-circuit protected.
• Output impedance: 510 Ω.
• Transducer power supply: -24 Vdc.
• Frequency response: fixed 1 Hz to 600 Hz for peak-peak filter; gap filter -3 dB at 0.09 Hz.
• Accuracy: within ±0.33% of full-scale typical, ±1% maximum for most measurements.
• Alarm setpoints adjustable from 0 to 100% of full-scale.

The monitor channels are programmed in pairs and can perform up to two functions simultaneously. For example, channels 1 and 2 can monitor rod position while channels 3 and 4 handle rod drop, or all four channels can focus on the same function.

Applications and Use Cases

The 3500/72-01-00 is specifically designed for reciprocating compressors. It measures rod position, rod drop, and hyper-compressor parameters. These measurements are essential for detecting wear, misalignment, or other issues that could lead to costly downtime.

In hyper-compressor monitoring, when both transducers are not OK, the monitor issues a danger alarm immediately. This rapid response helps prevent catastrophic failures. The monitor also supports continuous comparison of monitored parameters against alarm setpoints, triggering relays when needed.

Installation and Setup

Installation of the 3500/72-01-00 requires one full-height front slot in the 3500 rack. The I/O module occupies one full-height rear slot. The monitor module dimensions are 241.3 mm x 24.4 mm x 241.8 mm (9.50 in x 0.96 in x 9.52 in), and it weighs 0.91 kg (2.0 lb).

Configuration is performed using the 3500 Rack Configuration Software. This software allows you to set alert setpoints for each active measured value and danger setpoints for any two active measured values. You can also program alarm time delays from one to 60 seconds in one-second intervals.

Maintenance and Reliability

Regular inspection of the monitor and its connections is recommended to ensure reliable operation. The operating temperature range is -30°C to +65°C (-22°F to +149°F) when used with Internal/External Termination Proximitor/Seismic I/O Modules. Storage temperature range is -40°C to +85°C (-40°F to +185°F), with humidity up to 95% non-condensing.

Because the monitor is part of a safety-critical system, follow the manufacturer's manual for any maintenance procedures. Verify operation periodically to ensure alarms and relays function correctly.

Compatibility and Integration

The 3500/72-01-00 integrates seamlessly into the Bently Nevada 3500 rack system. It communicates with other modules in the rack, as indicated by the TX/RX LED. The front panel also includes an OK LED for operational status and a Bypass LED for bypass mode.

This monitor is compatible with proximity transducers and works with the 3500 Rack Configuration Software for setup and alarm configuration.

Troubleshooting and Common Issues

If the OK LED is not lit, the monitor may not be operating properly. Check the power supply and rack connections. If the TX/RX LED is not blinking, communication with other modules may be interrupted. Verify that the monitor is properly seated in the rack.

For alarm issues, ensure setpoints are within the transducer range. If the full-scale range exceeds the transducer range, the transducer range limits the setpoint. Alarm setpoint accuracy is within 0.13% of the desired value.

Product Support and Availability

The 3500/72-01-00 is available from AutoDCSTech. Please verify current lifecycle status and availability before ordering. Contact AutoDCSTech for pricing and delivery information.