Description

The 3500/61-02-00 is a six-channel temperature monitoring module designed for the Bently Nevada 3500 Machinery Protection System. The module accepts both RTD and thermocouple temperature inputs and performs continuous temperature measurement and alarm comparison functions for critical rotating machinery applications.

The 133827-02 RTD/TC Non-Isolated I/O Module uses external terminations and supports mixed RTD and TC input configurations. Users can configure individual channels through the 3500 Rack Configuration Software for RTD or thermocouple operation.

The 3500/61 series differs from the 3500/60 by providing recorder outputs for each monitoring channel. Recorder outputs support 4 to 20 mA transmission proportional to the configured monitor full-scale range.

The module supports up to six transducer inputs and provides programmable Alert and Danger alarm setpoints. In Triple Modular Redundant (TMR) systems, temperature monitors install adjacent in groups of three to support redundant voting logic and fault tolerance.

The module is suitable for turbine monitoring systems, compressor trains, process plants, power generation facilities, and industrial machinery protection applications requiring temperature supervision and alarm processing.

Features

• Six-channel temperature monitoring
• Supports RTD and thermocouple inputs
• Mixed RTD and TC channel configuration supported
• External termination non-isolated I/O design
• Recorder outputs for all six channels
• User-configurable alarm setpoints
• Software configurable RTD or TC measurement mode
• Compatible with 3500 Rack Configuration Software
• Supports TMR system architecture
• Front panel OK, TX/RX, and Bypass LEDs
• 4 to 20 mA recorder outputs
• Channel full-scale configuration through software
• No calibration required

Applications

• Steam turbine temperature monitoring
• Gas turbine protection systems
• Compressor temperature supervision
• Industrial rotating machinery monitoring
• Process plant shutdown systems
• Power generation equipment protection
• Petrochemical process monitoring
• LNG facility machinery monitoring
• Critical equipment alarm systems
• TMR machinery protection installations

Ordering Information

• 3500/61-02-00: Complete RTD/TC Monitor Kit with External Terminations
  • Specifies the combined kit containing the 3500/61 main monitor module and the specific non-isolated rear I/O board.
• -02: I/O Module Type Option
  • RTD/TC Non-isolated I/O Module with External Terminations (Rear Board Part Number: 133827-02).
• -00: Agency Approval Option
  • No hazardous area agency approvals or certifications required.
• Spares & Accessories
  • Part Number 133827-02: Replacement 3500/61 RTD/TC Non-Isolated I/O Module with External Terminations.

Technical Specifications

RTD Specifications

Thermocouple Specifications

Signal Conditioning Specifications

Outputs and Indicators

Engineering Notes

• Platinum RTD Selection: Platinum RTDs with a 0.00385 alpha coefficient conform to global industrial standards and are recommended for all new temperature loop deployments.
• Recorder Short-Circuit Immunity: Internal circuitry ensures that the core machinery monitoring and alarm logic remain unaffected by short circuits on external recorder loops.
• Under and Over Setpoints: The internal processing engine provides both upper and lower alarm bounds for multi-directional protection (e.g., cryogenic or overheating states).
• TMR Requirements: When configured for Triple Modular Redundancy, three identical temperature monitors must reside in consecutive, adjacent front-chassis slots.

Field Guidelines

• External Termination Wiring: Route all RTD or TC lead wires to the external termination block ensuring clean, gas-tight connections to maintain CJC accuracy.
• Shield Grounding: Terminate the cable shields exclusively at the designated shield grounding terminal on the I/O module to prevent ground loops and shield against electromagnetic noise.
• CJC Sensor Matching: Ensure the Cold Junction Compensation sensor is securely mounted to the terminal base for accurate ambient compensation during thermocouple measurements.
• Lead Resistance Minimization: For 3-wire and 4-wire RTD hookups, keep lead wire lengths identical to balance line-drop and ensure accurate bridge compensation.

Technical & Procurement FAQ

Q: What is the primary difference between the 3500/60 and the 3500/61 modules? A: Both modules provide identical temperature monitoring and alarm logic, but the 3500/61 features six independent +4 to +20 mA individual recorder outputs whereas the 3500/60 does not.

Q: Does this specific non-isolated I/O module option provide channel-to-channel isolation? A: No, this is the 02 option which is non-isolated; if channel-to-channel isolation is needed to counteract heavy ground faults or high-voltage line crossovers, the isolated I/O module version should be specified instead.

Q: Is field calibration required for the 3500/61 module upon installation? A: No field calibration is required as full-scale ranges and sensor types are configured digitally using the 3500 Rack Configuration Software.