3500/33-01-01 16-Channel Relay Module | Bently Nevada

Introduction to the 3500/33-01-01

When your machinery protection system needs dependable alarm outputs, the 3500/33-01-01 from Bently Nevada delivers. This 16-channel relay module is designed for use in 3500 rack-based monitoring systems, providing a robust interface between the monitor and your control or shutdown logic.

As a maintenance engineer, you need components that fail predictably and are easy to service. The 3500/33-01-01 addresses that need with epoxy-sealed relays and front-panel LEDs for quick status checks.

Key Features and Technical Specifications

The 3500/33-01-01 is a 16-channel relay output module. Each channel uses a single-pole double-throw (SPDT) relay, giving you flexibility in wiring both normally open and normally closed contacts.

• Relay type: SPDT, epoxy-sealed for environmental protection.
• Relay operation: Four groups of four channels are switch-selectable for normally de-energized (ND) or normally energized (NE) operation.
• Contact ratings: Max switched current 5 A; max switched voltage 125 Vdc or 250 Vac; max switched power 70 W @ 24 Vdc, 10 W @ 48 Vdc, 9 W @ 60 Vdc, or 1200 VA for AC.
• Minimum switched current: 100 mA @ 5 Vdc for standard relays; 1 mA @ 1 Vdc for low-current gold-plated relays.
• Relay contact life: 10,000 cycles.
• Arc suppressor: 250 Vrms installed as standard.
• Power consumption: 5.8 watts typical.
• Physical dimensions: Main module 241 mm x 24.4 mm x 242 mm; I/O module 241 mm x 24.4 mm x 99.1 mm.
• Weight: Main module 0.7 kg; I/O module 0.4 kg.

One distinctive feature is the ability to select ND or NE operation per group of four channels. This allows you to design failsafe logic: choose NE for alarms that should de-energize on trip, or ND for alarms that energize on trip. This flexibility simplifies integration with various safety schemes.

Applications and Use Cases

The 3500/33-01-01 is commonly used in rotating machinery protection systems, such as turbines, compressors, and pumps. It provides relay outputs for alarm and trip events, enabling connection to plant DCS or PLC systems.

For example, in a steam turbine application, the module can drive a shutdown solenoid through a normally energized relay. If the monitoring system detects an overspeed condition, the relay de-energizes, triggering a safe shutdown. The epoxy sealing protects the relay contacts from harsh environments, reducing nuisance failures.

Installation and Setup

Installation of the 3500/33-01-01 is straightforward. The main module occupies one full-height front slot in the 3500 rack, while the I/O module occupies one full-height rear slot. Ensure the rack is powered down before inserting or removing modules.

After mounting, configure the relay operation via the DIP switches on the module. Set each group of four channels to either ND or NE as required by your application. Wire the field contacts to the I/O module terminals, observing the contact ratings for your load.

Always verify that the switched voltage and current do not exceed the module's maximum ratings. Use the arc suppressor provided to protect contacts when switching inductive loads.

Maintenance and Reliability

Routine maintenance of the 3500/33-01-01 is minimal. Periodically inspect the module for signs of damage or contamination. Check that all wiring connections are tight and that the module is securely seated in the rack.

The relay contact life is rated at 10,000 cycles. In high-cycle applications, consider monitoring the number of operations and replace the module proactively to avoid unexpected failures. The front-panel LEDs provide a quick visual indication of module health: the OK LED illuminates when the module is operating properly, and the CH Alarm LED lights when any relay channel is in an alarm state.

Because the relays are epoxy-sealed, they are not serviceable. If a relay fails, replace the entire module. Keep a spare 3500/33-01-01 on hand to minimize downtime.

Compatibility and Integration

The 3500/33-01-01 is designed for use in Bently Nevada 3500 monitoring systems. It communicates with other modules in the rack via the internal backplane, as indicated by the TX/RX LED flashing during data transfer.

The module is available with hazardous area approval option 01, which is cNRTLus (Class 1, Division 2). This makes it suitable for installation in areas where flammable gases or vapors may be present under abnormal conditions.

For integration with your control system, the relay outputs can be wired directly to your PLC or DCS digital inputs. The SPDT contacts allow both NO and NC wiring, giving you flexibility in your logic design.

Troubleshooting Common Issues

If the OK LED is not illuminated, check that the module is properly seated and that the rack is powered. If the TX/RX LED is not flashing, verify communication with other modules.

If a relay channel does not operate as expected, check the DIP switch settings for that group. Ensure the wiring matches the selected mode (ND or NE). Also verify that the load is within the contact ratings.

For low-current applications, such as switching dry contacts, the standard relays may not be suitable because the minimum switched current is 100 mA @ 5 Vdc. In such cases, use the low-current gold-plated relay option, which can switch as low as 1 mA @ 1 Vdc.

Product Support and Availability

The 3500/33-01-01 is available from AutoDCSTech. Please verify current lifecycle status and availability before ordering. Our team can assist with technical questions and provide documentation.