A Complete Guide on Bently Nevada 3500 System Components

The 3500 System provides continuous, online monitoring suitable for machinery protection applications. It is designed to meet the API 670 standard for such systems established by the American Petroleum Institute. The 3500 System is designed to monitor rotating and reciprocating machinery in a variety of industries continuously and permanently. It is intended for use in auto-shutdown machinery protection applications requiring extreme reliability and availability.

3500 System Components

Instrument Rack

The 3500 Rack standard is available in 19″ EIA rail-mount, panel-cutout-mount, and bulkhead-mount configurations. In the left-most rack positions, there are slots for two Power Supplies and a TDI that are reserved exclusively for these modules. The remaining 14 rack slots can hold any combination of monitor, display, relay, Keyphasor module, and communication gateway modules.

All modules consist of the main module and an associated I/O module that plug into the rack’s backplane. For panel-mount systems, the I/O module is installed at the back of the rack. For bulkhead-mount systems, it is installed above the main module. The depth of a standard rack is 349 mm (13.75 inches), while the depth of a bulkhead-mounted rack is 267 mm (10.5 inches). NEMA 4 and 4X weatherproof housings are available when environmental protection or purge air are required.

Mini Rack

A mini rack (12″ wide rather than 19″) is also available, with 7 monitor slots rather than 14. The left-most slots, like its larger counterpart, are reserved for the Power Supply or Supplies and TDI Module. The mini rack can be installed in a panel cutout or on 19″ EIA mounting rails with an optional adapter plate. Bulkhead mounting is not an option.

Power Supply

The 3500/15 Power Supply can be ordered with either ac or dc input power, making it compatible with voltage sources all over the world. Line noise filters are commonplace. The 3500 Rack can operate on a single supply or dual supplies to provide redundancy in situations where power interruption is not tolerated. The upper and lower positions of the left-most rack slot house dual supplies. Separate voltage sources can be used for redundant supplies. The primary (lower) supply, for example, can be powered by 120 Vac. While the backup (upper) supply can be powered by an uninterruptible 24 Vdc source. Each supply can independently power the entire rack and its modules.

When redundant supplies are used, the lower supply serves as the primary power supply for the rack, while the upper supply serves as a backup, ready to operate as the primary rack supply instantly and automatically if the direct supply fails. The self-monitoring functions of the 3500/15 Power Supply module allow it to determine whether all of its output voltages are within specifications. The module indicates this with a green Supply OK LED on the front panel of the power supply.

Transient Data Interface (TDI)

The TDI is the primary interface between the 3500 Rack and the configuration, display, and condition monitoring software. Each rack requires one TDI, which must be installed in the rack slot directly adjacent to the power supply slot. The TDI supports a proprietary protocol that the 3500 Configuration Software. The 3500 Operator Display Software use to configure the rack and retrieve rack data and statuses.

The TDI can also communicate directly with System 1 Condition Monitoring and Diagnostic software. Eliminating the need for an external communications processor. The Rack OK relay is housed within the I/O module of the TDI. It is caused by NOT OK conditions within the TDI and other modules in the rack.

Monitor Modules

Each monitor takes up one of the 14 available slots in the rack. Microprocessor-based monitors provide digitally adjustable Alert and Danger setpoints for each channel. Alarms can be configured to operate in either latching or non-latching mode. Front-panel LEDs provide status indications for each monitor, allowing observation without operator interaction for convenient operation. For connection to associated industrial systems, most monitors provide independent 4 to 20 mA proportional outputs for each channel of the I/O module.

Where applicable, the I/O modules supply power to transducers via short-circuit-protected terminals. Each monitor’s OK detection routines continuously check the integrity of each transducer and associated field wiring. Except for the 3500/60, /61, /65 (temperature), and /62 (process variable) monitors, transducer input signals are buffered and sent to front-panel BNC connectors.

Relay Modules

The 3500/32M and 3500/33 Relay Modules contain a set of relays that can be programmed to activate in response to alarm conditions in other monitor modules in the rack. The /32M module (on the left) employs double pole double throw (DPDT) relays. Whereas the /33 module (on the right) employs single pole double throw (SPDT) relays. The /32M module contains four DPDT relay channels, while the /33 unit contains sixteen SPDT relay channels.

The /33 can also be set up to act like it has DPDT relays. This will use two SPDT relays to perform the function of each configured DPDT relay. Although relay modules are not a required component of the 3500 System. They are the best way to integrate the 3500 System with automatic shutdown applications. In any of the slots to the right of the TDI, any number of relay modules can be installed. The 3500 System Configuration software makes it easy to program “Alarm Drive Logic,” which controls relay actuation.

This logic can be based on a variety of alarm combinations, ranging from the Alert, Danger, or NOT OK status of a single channel to highly complex Boolean expressions that combine two or more channel statuses to provide special AND or OR voting.

Keyphasor Module

The 3500/25 is a half-height module that powers and terminates up to two Keyphasor transducers. Install a single 3500/25 module for applications that require one or two Keyphasor transducers. By installing two 3500/25 Keyphasor modules in the rack, the 3500 System can accommodate up to four Keyphasor transducers. When using two 3500/25 Keyphasor modules, they must be installed one above the other in the same rack slot. Keyphasor signals from the 3500/25 module(s) can be routed via the 3500’s rack backplane to appropriate monitor modules for use in speed, phase, tracking filter, and other measurements.

Communication Gateway

A 3500 system can digitally transfer selected status and current value data to process control systems, historians, plant computers, and other relevant systems using Communication Gateway modules. Integration with EGD compatible control systems, such as the GE Mark VIe, is possible with the 3500/91 Ethernet Global Data (EGD) Comm Gateway Module.

Modbus communication is supported by the 3500/92 Comm Gateway Module via serial and Ethernet protocols. When a system requires redundant communication or must support multiple communication protocols at the same time; multiple communication gateway modules can be installed in a rack. The modules do not interfere with the 3500 System’s normal operations or machinery protection functions. Ensuring that the monitoring system integrity is always maintained, even if a Communication Gateway module fails in the unlikely event.

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