Bentley 3300/35-03-01-02-00-00 Six-Channel RTD Temperature Monitoring Module Detailed Product Description

I. Product Overview

The Bentley 3300/35-03-01-02-00-00 is a six-channel RTD temperature monitoring module within the 3300 series TSI (Turbo Generator Instrumentation) system of Baker Hughes (formerly GE Bentley Nevada). It is specifically designed for high-precision temperature monitoring and over-limit protection of key parts of large rotating machinery (such as steam turbines, gas turbines, generators, compressors, etc.) in industries such as thermal power, nuclear power, petrochemicals, and metallurgy. The module adopts a 19-inch standard rack structure, supports hot-swapping, and can be mixed with other monitoring modules of the 3300 series to share the backplane - 24V DC power supply and system bus; it is compatible with Pt100 platinum resistance (RTD), with a measurement range of 0–600°C, providing six independent temperature measurements, dual-level alarms, six independent 4–20mA isolated analog outputs, and complete self-diagnosis functions, in accordance with API 670 standards. It is the core equipment for temperature status monitoring and fault protection of rotating machinery.

II. Model Coding Rules (3300/35-AA-BB-CC-DD-EE)

3300: Bentley 3300 modular TSI system, unified rack, centralized power supply, hot-swappable architecture.

35: Function code, representing a six-channel temperature monitoring module, independently monitoring 6 temperature signals.

03: Range code, corresponding to **0–600°C** measurement range, suitable for the high-temperature section of Pt100 RTD, covering critical measurement points such as bearings, stators, windings, lubricating oil, etc.

01: Sensor type code, suitable for Pt100 platinum resistance (RTD), industrial standard high-precision resistance-type temperature sensor configuration.

02: Relay and output configuration code, equipped with two SPST sealed alarm relays + 6 independent isolated 4–20mA analog outputs.

00: Certification level code, representing general industrial-level certification, suitable for routine industrial environments.

00: Safety barrier configuration code, representing no built-in safety barrier, only applicable to non-explosion-proof areas.

III. Core Functions

1. Six-channel high-precision RTD temperature measurement

Independent 6 RTD inputs, each adapted to Pt100 platinum resistance (three-wire system), measurement range 0–600°C, covering normal operation and abnormal overheating intervals of rotating machinery. Using high-precision constant current sources and signal conditioning circuits, measurement accuracy ≤ ±0.1°C (25°C reference point), resolution up to 0.1°C, capable of accurately capturing minor temperature changes. Real-time monitoring of RTD circuit status, early warning of wire breakage, short circuit, incorrect wiring, poor contact, etc., suitable for complex industrial environments with strong electromagnetic interference and severe vibration.

2. Dual-level alarm and sealed relay output

Each channel independently configured **alert (ALERT), danger (DANGER)** two-level alarm thresholds, configurable through panel local configuration or remote setting, suitable for different equipment temperature protection requirements. Equipped with 2 epoxy resin sealed SPST relays, contact specifications 250V AC/5A, 30V DC/5A, moisture-proof, dust-proof, vibration-resistant, directly driving audible and visual alarms, DCS/PLC interlock circuits or shutdown protection devices. Alarm delay adjustable from 0 to 10 seconds, filtering instantaneous temperature fluctuations, avoiding false alarms; relay status and module operation status are linked, automatically triggering alarms when faults occur, ensuring timely response to abnormal temperature conditions.

3. On-site display and convenient configuration The front panel is equipped with an LCD digital display window and multiple sets of status LED indicators, which can display the real-time temperature measurement values of 6 channels, RTD circuit resistance, alarm thresholds, and fault codes. There are four sets of LEDs: OK, ALERT, DANGER, and BYPASS, corresponding to normal operation, warning alarm, dangerous alarm, and module bypass status respectively. The operation status is clearly visible. It supports on-site configuration via buttons, allowing for range calibration, RTD type matching, alarm threshold configuration, delay parameter adjustment, and loop diagnosis settings without the need for an upper computer. The operation is efficient and convenient, reducing the difficulty of on-site maintenance.

4. Six independent isolated analog signal outputs

Provide 6 independent isolated buffered analog outputs (1 output per channel), with a fixed output of 4–20mA current signal. The output signal is electrically isolated from the power supply, input signal, and has a strength of ≥2500V AC, effectively suppressing electromagnetic interference and ground loop current in industrial environments. The output content is the real-time temperature value, which can be connected to recorders, DCS systems or data acquisition platforms for temperature trend analysis, fault tracing and data archiving, supporting equipment status assessment and preventive maintenance, and meeting the data connection requirements of industrial automation systems.

5. Comprehensive self-diagnosis and fault identification

24-hour continuous monitoring of the module's own hardware, RTD circuit, power supply status and signal integrity. It can accurately identify RTD open circuit / short circuit, wiring errors, constant current source abnormalities, power fluctuations, module circuit faults, etc. It distinguishes between real temperature anomalies and sensor / circuit faults. The panel LEDs clearly indicate the fault type, and in combination with on-site display of fault codes, it facilitates rapid troubleshooting and maintenance, reducing the risk of unplanned shutdown caused by temperature faults.

6. System integration and strong anti-interference capability

The metal shielding shell design, multiple electrical isolation between input, output and power supply circuits, suitable for industrial environments with strong electromagnetic interference and high vibration such as thermal power, nuclear power, and petrochemicals. Compatible with the 3300 series system bus (Type A), can be connected to the Bently System 1 equipment status monitoring platform to achieve remote configuration, real-time data transmission, historical trend query, fault warning analysis and other functions, integrating into the enterprise equipment management system. Supports seamless integration with DCS, PLC and other third-party systems to meet factory automation integration requirements, ensuring stable transmission of temperature monitoring data.

4. Detailed technical parameters

Measurement parameters

Monitoring channels: 6 independent temperature measurements (compatible with Pt100 RTD, three-wire system)

Sensor type: Pt100 platinum resistance (RTD), three-wire system

Measurement range: 0–600℃

Measurement accuracy: ≤±0.1℃ (25℃ reference point, typical value)

Resolution: 0.1℃

Loop current: Constant 1mA per channel

Response time: ≤5 seconds (reaching 90% stable reading)

Input impedance: ≥1MΩ (per channel)

Electrical parameters

Working power supply: -24V DC (±10%), backplane power supply; supports short circuit switching - 18V DC

Power consumption: typical 2.5W, maximum ≤4W

Relay output: 2 SPST (ALERT+DANGER), epoxy resin sealed, 250V AC/5A, 30V DC/5A

Analog output: 6 isolated 4–20mA current signals, load resistance ≤500Ω

Isolation strength: ≥2500V AC between input/output/power supply

Sensor power supply: Module internal constant current source power supply, no external power supply required

Environmental and mechanical parameters

Operating temperature: 0℃~+65℃ (standard industrial grade)

Storage temperature: -40℃~+85℃

Relative humidity: 5%–95% (no condensation) Vibration tolerance: Compliant with IEC 60068-2 standards, resistant to vibration and shock

Installation method: 19-inch standard rack slot, supports hot swapping

Dimensions: 203mm (height) × 330mm (depth) × 51mm (width)

Weight: Approximately 1.2kg

Protection level: IP20 (suitable for installation in control cabinets)

Certifications and compliance

Industry standards: Compliant with API 670 Rotating Machinery Monitoring and Protection Standards

Electromagnetic compatibility: CE certification, compliant with EN 61000-6-2/4

Safety certification: UL certification

Environmental compliance: RoHS Directive compliance

VII. Typical application scenarios

Power industry (thermal power / nuclear power turbine / generator): Multiple measurement points for monitoring bearing temperature, stator winding temperature, core temperature, lubricating oil temperature, prevent overheating-induced insulation aging, bearing bush burning, equipment damage; temperature protection during startup acceleration, normal operation, shutdown rotation throughout the stage, over-temperature triggers alarm or interlock shutdown, ensuring safe and stable operation of the unit; 

Petrochemical industry (large-scale process compressors / cracking turbines): Synchronous monitoring of multiple bearing temperatures, sealing chamber temperatures, medium outlet temperatures, lubricating oil tank temperatures, suitable for high-temperature, high-pressure, and highly corrosive industrial environments, prevent overheating-induced bearing bush wear, sealing failure, medium leakage and other accidents, ensuring continuous industrial production.

Metallurgical industry (large-scale transmission turbines / fans / motors): Batch monitoring of key bearing temperatures, equipment shell temperatures, cooling medium outlet temperatures, winding temperatures, dual-level alarm linkage with equipment operation interlock, timely warning of overheating faults, reducing unplanned shutdown risks, ensuring stable and efficient operation of the metallurgical process.

VIII. Installation and commissioning specifications

Installation requirements

Rack installation: Push smoothly into the vacant slot of the 3300 series rack, ensure that the rear connectors are fully engaged, tighten the panel fixing screws to avoid loosening and contact failure; reserve ventilation space at the installation location to avoid heat accumulation affecting module heat dissipation.

Sensor wiring: Pt100 RTD uses three-wire connection, distinguish A/B/C lines according to module terminal markings, select high-temperature-resistant shielded cables, single-ended grounding of the shielding layer (on the control cabinet side), to avoid circulating interference; during wiring, avoid bending or pulling the cables, prevent breakage or signal attenuation.

Alarm and output wiring: Distinguish ALERT and DANGER relay contacts, connect to the alarm/interlock circuit; connect analog output terminals according to DCS/record仪 interface requirements， confirm correct signal polarity to ensure stable transmission of 4–20mA signals.

Sensor installation： RTD probe is close to the surface of the measured equipment， fixed with thermal adhesive or clamps to ensure accurate temperature measurement； fix the probe cable firmly to avoid vibration wear or cable breakage， keep away from strong electromagnetic radiation sources.

Commissioning steps

Power-on self-check： The module powers on and automatically performs self-check， the OK light is constantly on indicating normal hardware， when the fault light is on， troubleshoot wiring， sensors or hardware issues.

Sensor calibration： Enter calibration mode through the panel buttons， select Pt100 RTD type， calibrate the circuit resistance parameters to ensure temperature measurement accuracy.

Alarm settings： Set warning thresholds (e.g. 120°C) and danger thresholds (e.g. 150°C)， adjust alarm delay (e.g. 2 seconds)， save parameters.

Signal verification： During equipment operation， observe whether the 6-channel temperature values on the panel are stable， without jumps， drifts； check that the RTD circuit has no fault indication， confirm the signal is correct before putting into operation. Check that the terminal connections of the module are not loose or oxidized, and that the ventilation and heat dissipation of the rack are good.

Annual calibration: Use a standard resistance box to calibrate the temperature measurement accuracy every year, verify the alarm action values and delay accuracy of the relays, and ensure the reliability of monitoring and protection functions.

Cleaning and protection: Regularly clean the dust on the module surface with a dry soft cloth to avoid dust accumulation affecting heat dissipation; strictly prohibit liquids and metal debris from entering the module interior to prevent short-circuit faults.

Common fault troubleshooting

OK light goes out (module failure): Check if the backplane power supply is normal (-24V DC), reinsert and re-execute the module, if still abnormal, replace the module.

Abnormal temperature display (jumps / drifts): Check if the Pt100 RTD wiring is loose, wrongly connected, or broken, and if the shielding cable is damaged, rewire or replace the sensor; check if the environmental temperature exceeds the working range and if there is strong electromagnetic interference.

No temperature display: Check if the RTD is damaged, if the wiring is incorrect, if the module constant current source is abnormal, and troubleshoot and replace the faulty components.

Alarm mis-triggering: Re-calibrate the alarm threshold and delay parameters, check if the temperature signal is interfered with, optimize the sensor installation and shielding measures.

VIII. Usage Notes

This model is of non-explosion-proof design. Installation and use are strictly prohibited in flammable and explosive hazardous areas.

It must be equipped with **Pt100 platinum resistance (three-wire RTD)** temperature sensors. Other types of sensors (such as K-type thermocouple, Pt1000) must not be mixed. Otherwise, it will cause measurement errors or equipment damage.

It is only applicable for temperature monitoring within 0–600℃. For over-temperature scenarios, select the corresponding range module.

Do not disassemble the module, modify the internal circuitry, or replace non-original accessories without authorization. Illegal operations will result in the invalidation of equipment warranty and may cause safety hazards.

Before connecting or inspecting the module, cut off the main power supply of the rack to prevent short circuits and electric shock accidents; do not plug or unplug the module while it is powered on.

When the module is in a long-term shutdown state, it is recommended to remove the module from the rack, store it in a dry and cool environment to avoid moisture and dust affecting performance.