Bently Nevada 3500/32 4-channel relay module

Bently Nevada  3500/32  4-channel relay module

Detailed explanation of working principle

1. Core functional architecture

The 3500/32 relay module, as part of the Bently Nevada 3500 monitoring system, mainly functions to trigger alarm or

 interlock actions based on mechanical condition monitoring data. Its core components include:

Microprocessor unit: It is responsible for receiving the monitor channel data (such as vibration, temperature and other

 parameters) sent from the frame backplane and determining whether to trigger the relay action based on the preset

 logic.

Relay drive circuit: When the microprocessor detects that the alarm condition is met, it sends a signal to the drive 

circuit to control the relay coil to be powered on/off, achieving the switching of contact states.

Communication interface: Communicate with other modules (such as monitors, frame interface modules) through the 

3500 system backplane to obtain real-time monitoring data and feedback the relay status.

2. Signal processing and logical judgment process

Data collection

The monitor module (such as the 3500/42 vibration monitor) converts the raw data collected by the sensor (such as 

vibration amplitude and phase) into engineering units (such as μm, mm/s), and transmits it to the 3500/32 module 

through the backplane bus.

Alarm threshold comparison

The 3500/32 module receives the current values of each monitoring channel and compares them with the

pre-configured Warning and Danger thresholds. For example:

When the vibration amplitude exceeds the warning threshold but does not reach the dangerous threshold, the 

"warning" logic is triggered.

When the vibration amplitude exceeds the danger threshold, the "danger" logic is triggered.

Voting logic execution:

The module supports three alarm driver logic modes:

Bus relay mode: Alarm signals from multiple monitoring channels are summarized through "OR gate" logic. Once any 

channel alarms, the relay is triggered to act.

Single relay mode: The relay only responds to the alarm signal of a specific monitoring channel (such as a channel that 

only monitors the bearing temperature).

Independent relay mode: By combining alarm signals from multiple channels through "AND gates" or "OR gates", 

complex logic is achieved (for example, the relay is triggered only when both vibration and temperature exceed the

 limit).

3. Relay action mechanism

Coil control

When the microprocessor determines that the alarm condition is met, it outputs a high-level signal to the relay drive

 circuit to energiize the coil (rated voltage 24Vdc).

The coil generates a magnetic field that attracts the armature, causing the normally open contact (NO) to close and 

the normally closed contact (NC) to open.

Contact state maintenance:

The relay adopts a magnetic latch design. After the coil is energized, the contact state will be locked. Even if the coil is

 de-energized, it will remain in the current state until a reset signal is received.

Contact capacity and lifespan:

The rated voltage of the contact is 250Vrms, and the maximum current is 5A (24Vdc/240Vdc). It can directly drive small

 loads (such as indicator lights, solenoid valves) or control larger loads through an intermediate relay.

The mechanical life is ≥10? operations, and the electrical life is ≥10? full-load operations, ensuring long-term reliable

 operation.

4. Status indication and Feedback

LED indicator light

OK LED: It flashes once per second during normal operation. If it goes off or remains on constantly, it indicates a 

module failure (such as abnormal power supply or processor freeze).

TX/RX LED: It flashes when communication with other modules in the frame is normal and turns off when 

communication is interrupted. It is used to diagnose backplane communication faults.

CH ALARM LED: It lights up when the corresponding channel relay triggers an alarm. It can be set to "locked" or 

"non-locked" mode through software configuration (the locked mode requires manual reset, and the non-locked 

mode automatically resets after the alarm condition disappears).

Status feedback signal:

The relay module can feed back the current contact status (such as normal, warning, dangerous) to the monitoring

 system through the backplane, facilitating the recording and display by the upper computer software.

5. Collaborative work with the 3500 system

Power Supply and Communication

The module acquires a 24Vdc power supply through the 3500 frame backplane and communicates with other modules

 using the RS-485 protocol, with a transmission rate as high as 115.2kbps.

Redundancy and Fault Tolerance

In the redundantly configured 3500 system, the primary and backup relay modules receive monitoring data 

synchronously. When the primary module fails, the backup module automatically takes over the control to ensure the

 continuous alarm function.

Software configuration

The relay module can be set as follows using the 3500/VM or DE software of Bently Nevada:

Define the alarm threshold and lag amount (for example, the danger threshold is 100μm and the lag amount is 10μm, 

that is, it needs to be reduced to 90μm after the alarm to reset);

Configure the relay output mode (always on/always off);

Set the alarm delay (for example, the relay operates only after the alarm signal lasts for 2 seconds to avoid

misoperation caused by interference).