Description
The Bently Nevada 125720-01 is a high-performance 4-Channel Relay Output Module specifically engineered for the 3500 Series Machinery Protection System. It provides essential switching capabilities to trigger alarms, annunciators, or machine shutdown sequences based on monitored vibration, position, or temperature data.
Product Introduction
The Bently Nevada 125720-01 is a full-height I/O module that interfaces with the 3500/32 Relay Module. It acts as the physical connection point for the relay contacts, allowing the system to execute voting logic and drive external devices. Designed for mission-critical reliability, the 125720-01 Relay Module ensures that protective actions are taken instantaneously when machinery parameters exceed safety thresholds.
BENTLY 125720-01
Technical Specifications (Datasheet)
The following parameters detail the electrical and physical characteristics of the module:
| Parameter | Specification |
| Relay Channels | 4 Channels (Independently Programmable) |
| Relay Type | Single-Pole, Double-Throw (SPDT) |
| Max Switched Voltage | 250 Vrms (AC) / 125 Vdc (DC) |
| Max Switched Current | 2 A @ 30 Vdc / 2 A @ 250 Vac |
| Contact Life | 100,000 cycles @ 5 A, 24 Vdc |
| Operating Temperature | -30°C to +65°C (-22°F to +150°F) |
| Storage Temperature | -40°C to +85°C (-40°F to +185°F) |
| Dimensions (H x W x D) | 241 mm x 24.4 mm x 99.1 mm |
| Weight | 0.4 kg (1.0 lb) |
| Country of Origin | USA |
Usage & Installation Instructions
The 125720-01 is installed into the rear of the 3500 rack, directly behind its corresponding 3500/32 main module.
- Slot Placement: Any number of relay modules can be placed in slots to the right of the Rack Interface Module (RIM).
- Configuration: Use the 3500 Rack Configuration Software to program the “Alarm Drive Logic.” This allows for complex AND/OR voting logic using alert and danger statuses from any monitor channel in the rack.
- Wiring: Field wiring is connected to the terminal blocks on the I/O module. Ensure that the wire gauge is appropriate for the current load to prevent overheating.
- Redundancy: For enhanced safety, the relays can be configured in “Normally Energized” or “Normally De-energized” states depending on your fail-safe requirements.
Product Features
- Independently Programmable: Each of the four relays can be assigned to different monitor channels or voting groups.
- Alarm Drive Logic: Supports sophisticated logic combinations for voting (e.g., 2-out-of-3 logic).
- Sealing: Relays are typically epoxy-sealed to prevent contamination and ensure long-term contact reliability.
- Diagnostics: Features “OK” LEDs and channel status indicators to provide local visibility of the module’s health.
Recommended Similar Models
For users maintaining 3500 series systems or requiring different relay configurations, consider these related models:
- Bently Nevada 125720-02: A spare 4-channel relay output module designed for standard (non-hazardous) systems.
- Bently Nevada 149986-02: The matching 3500/32M Spare 4-Channel Relay Control Module (Main Module).
- Bently Nevada 125712-01: The 3500/32 4-Channel Relay Control Module.
- Bently Nevada 133396-01: A 16-channel Relay I/O Module for high-density switching requirements.
- Bently Nevada 125800-01: An I/O module used with the 3500/33 16-Channel Relay System.
