Bentley 3300/35-02-02-02-00-00 Six-Channel Thermocouple Temperature Monitoring Module Detailed Product Description

I. Product Overview

The Bentley 3300/35-02-02-02-00-00 is a six-channel thermocouple (TC) 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 high-temperature measurement points in 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 K-type thermocouples, with a measurement range of 0–1200°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 monitoring and fault protection of rotating machinery in high-temperature conditions.

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.

02: Range code, corresponding to **0–1200°C** measurement range, suitable for K-type thermocouples in the high-temperature section, covering high-temperature measurement points such as steam turbine casings, exhaust, gas turbine combustion chambers, etc.

02: Sensor type code, suitable for K-type thermocouples (TC), an industrial standard high-temperature thermocouple 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 K-type thermocouple temperature measurement

Independent 6 channels of thermocouple input, each channel compatible with K-type thermocouples, measurement range 0–1200°C, covering normal operation and abnormal overheating intervals of rotating machinery. High-precision cold junction compensation and signal conditioning circuits are adopted, measurement accuracy ≤ ±0.5°C (25°C reference point), resolution up to 0.1°C, capable of accurately capturing minute temperature changes in the high-temperature section. Real-time monitoring of the thermocouple circuit status, early warning of wire breakage, short circuit, incorrect wiring, compensation wire abnormalities, 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 with **ALERT (warning) and DANGER (dangerous)** two-level alarm thresholds, configurable through panel local configuration or remote setting, suitable for different high-temperature protection requirements of different equipment. 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 high-temperature anomalies.

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 real-time 6-channel temperature measurements, thermocouple 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, thermocouple type matching, cold junction compensation settings, 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 integration requirements of industrial automation systems.

5. Comprehensive self-diagnosis and fault identification

24-hour continuous monitoring of the module's own hardware, thermocouple circuit, cold junction compensation status, power supply status and signal integrity. It can accurately identify issues such as thermocouple breakage / short circuit, compensation wire errors, cold junction compensation anomalies, power fluctuations, module circuit faults. It distinguishes between real temperature anomalies and sensor / circuit faults. The panel LEDs clearly indicate the fault type, and the fault code is displayed on-site to facilitate quick troubleshooting and maintenance, reducing the risk of unplanned shutdown due to high-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 K-type thermocouples)

Sensor type: K-type thermocouple (nickel-chromium - nickel-silicon)

Measurement range: 0–1200℃

Measurement accuracy: ≤±0.5℃ (25℃ reference point, typical value)

Resolution: 0.1℃

Cold junction compensation: Built-in automatic cold junction compensation, compensation range 0–50℃

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

Input impedance: ≥10MΩ (per channel)

Electrical parameters

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

Power consumption: typical 2.8W, maximum ≤4.5W

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: Input / output / power supply ≥2500V AC

Sensor power supply: No external power supply required, thermocouple self-generated signal input

Environmental and mechanical parameters

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

Storage temperature: -40℃~+85℃ Relative humidity: 5%–95% (no condensation)

Vibration tolerance: Complies 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 1.3kg

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

Certifications and compliance

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

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

Safety certification: UL certification

Environmental compliance: RoHS Directive compliance

V, Typical application scenarios

Power industry (thermal power / nuclear power turbine / gas turbine): Multiple measurement points for monitoring turbine cylinder temperature, exhaust temperature, gas turbine combustion chamber temperature, exhaust gas temperature, prevent overheating leading to material aging, component deformation, equipment damage; full-stage high-temperature protection during startup acceleration, normal operation, shutdown rotation, triggered by overheating and alarm or interlock shutdown to ensure safe and stable operation of the unit.

Petrochemical industry (large cracking turbines / process heating furnaces): Synchronous monitoring of turbine high-temperature bearing temperature, sealing chamber temperature, heating furnace outlet temperature, reaction medium temperature, suitable for high-temperature, high-pressure, and highly corrosive industrial environments, prevent equipment burnout, medium cracking, and safety accidents, ensure continuous industrial production.

Metallurgical industry (large heating furnaces / sintering machines / high-temperature fans): Batch monitoring of furnace interior temperature, flue gas temperature, equipment high-temperature shell temperature, winding temperature, dual-level alarm linkage for equipment operation interlock, timely warning of overheating faults, reduce unplanned shutdown risks, ensure stable and efficient operation of the metallurgical process.

VI, 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: K-type thermocouple uses positive and negative polarity separation wiring (positive nickel-chromium, negative nickel-silicon), equipped with dedicated K-type compensation cables, select high-temperature-resistant shielded cables, single-ended grounding of the shielding layer (on the control cabinet side), 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; analog output terminals are connected according to the requirements of DCS/recorders interfaces, confirm the correct signal polarity to ensure stable transmission of 4–20mA signals.

Sensor installation: Thermocouple probe is tightly attached to the high-temperature surface of the measured equipment, fixed using a high-temperature clamp to ensure accurate temperature measurement; the probe cable is firmly fixed to avoid vibration wear or breakage, away from strong electromagnetic radiation sources.

Commissioning steps

Power-on self-check: The module automatically performs self-check after power-on, 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 K-type thermocouple type, enable automatic cold junction compensation, calibrate the loop resistance parameters to ensure temperature measurement accuracy.

Alarm settings: According to the equipment operation standards, set warning thresholds (such as 800°C) and dangerous thresholds (such as 1000°C), adjust alarm delay (such as 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 thermocouple circuit has no fault indication, confirm the signal is correct before putting into operation.

VII, Maintenance and fault troubleshooting

Daily maintenance Regular inspection: Daily observation of panel temperature values, circuit status and LED status, confirming no alarms or fault indications; checking that module terminal connections are not loose or oxidized, and that the rack ventilation and cooling are in good condition.

Annual calibration: Using standard thermocouples to calibrate temperature measurement accuracy, verifying the accuracy of relay alarm action values and delay, ensuring reliable monitoring and protection functions.

Cleaning and protection: Regularly cleaning module surface dust with a dry soft cloth to avoid dust accumulation affecting heat dissipation; strictly prohibiting 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-examine the module; if still abnormal, replace the module.

Abnormal temperature display (jumps / drifts): Check if the K-type thermocouple wiring is loose, miswired, or broken, and if the compensation wires are matched, damaged, and rewire or replace the sensor; check if the environmental temperature is beyond the working range and if there is strong electromagnetic interference.

No temperature display: Check if the thermocouple is damaged, if the positive and negative poles are connected reversely, if the compensation wire is open-circuited, and troubleshoot and replace faulty components.

Alarm mis-triggering: Re-calibrate the alarm threshold and delay parameters, check if the cold junction compensation is abnormal, optimize sensor installation and wiring 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 **K-type thermocouple (nickel-chromium - nickel-silicon)** temperature sensor and dedicated K-type compensation wires. Mixing with other types of thermocouples (such as S-type, B-type) or RTD is not allowed; otherwise, it will cause measurement errors or equipment damage.

It is only applicable for temperature monitoring within 0–1200℃. 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.