1. General Information

• Manufacturer: Bently Nevada (Baker Hughes)

• Model Number: 3500/20

• Spare Part Number: 125760-01

• Product Name: Rack Interface Module (RIM)

• Series: 3500 Machinery Protection System

• Module Type: Half‑height basic communication interface module (Old generation)

• Application: Acts as basic rack communication gateway, transmits steady-state data, rack status and configuration information; does not support high-speed transient waveform data.

• Installation Rule: Must be installed in Slot 1 of 3500 rack

• Compliance: API 670

2. Communication Interface

• Serial Port: RS232 / RS422 configurable

• Ethernet: No built-in Ethernet port (External HIM module required)

• Data Type: Only steady-state data, without transient waveform & spectrum data

• Protocol: Bently Nevada proprietary protocol, limited Modbus function

3. Electrical Specifications

• Backplane Power: +5 VDC from rack backplane

• Power Consumption: 4.5 W typical

• Isolation Voltage: 1500 VAC isolation between communication port and system

• Data Sampling Rate: Low speed, no high-speed transient acquisition capability

4. Environmental Specifications

• Operating Temperature: -30 °C ~ +65 °C (-22 °F ~ +149 °F)

• Storage Temperature: -40 °C ~ +85 °C (-40 °F ~ +185 °F)

• Relative Humidity: 5% ~ 95% (Non-condensing)

• Anti-vibration: Compliant with API 670 industrial vibration standard

5. Mechanical Specifications

• Structure: Half‑height single slot module

• Dimensions (H × W × D): 241 × 12.2 × 112 mm

• Weight: Approximately 0.41 kg

• Mounting: 3500 standard rack slot installation, hot-swap capable

6. Compatible Devices

7. Key Features

• Basic rack data communication and configuration management

• Simple serial communication for DCS and configuration software

• Low power consumption, stable operation for basic monitoring rack

• Half-height compact design to save rack slot resources

• Mandatory Slot 1 installation for system bus synchronization

8. Difference Between 3500/20 & 3500/22M

• 3500/20 (125760-01): Old version, no Ethernet, no transient waveform, RS232/RS422 only, basic RIM.

• 3500/22M: New version, built-in Ethernet, high-speed transient & spectrum data, TDI integrated, replace 3500/20.