Selecting a chassis for a 3U Eurocard system involves more than matching board height to rack height. The enclosure must provide controlled card alignment, usable rear I/O, predictable cooling, serviceable power, and sufficient mechanical depth for the intended backplane and transition hardware.
The Vector Series 2345 addresses these requirements in a 4U rackmount format measuring 6.97 inches in height and 19 inches in width. Its dual-cage architecture separates the primary front card cage from the rear transition-module cage, allowing system designers to retain a compact enclosure while supporting both board-level integration and rear-access cabling.
Mechanical architecture for vertical 3U cards
The Series 2345 is designed around a front cage for 3U x 160 mm boards and a rear cage for 3U x 80 mm transition modules. This arrangement follows the dimensional conventions used by several vertical Eurocard-based architectures, including VME, VME64x, CompactPCI, PXI, and selected VPX implementations.
The enclosure provides:
- 4U overall height: 6.97 inches
- 19-inch rack width: compatible with EIA-310-D rack equipment dimensions
- Front card cage: 3U x 160 mm
- Rear transition-module cage: 3U x 80 mm
- Chassis depth: 11.65 inches
- Flammability rating: UL94V-0
The 4U enclosure height provides the mechanical space required for a 3U card system while allowing room for card guides, backplane hardware, power entry, cooling components, and structural members. The additional vertical space is used to support service access and thermal management rather than simply increasing the usable board area.
The front card cage establishes the primary mechanical datum for plug-in boards. Card guides maintain alignment between board edges and backplane connectors, reducing the risk of connector damage during insertion and removal. The rear cage provides a defined location for transition modules without requiring rear I/O hardware to occupy the same mechanical space as the front payload cards.
Standards compatibility and backplane selection
The Series 2345 can be configured for backplane architectures associated with VME, VME64x, CompactPCI, PXI, and VPX. Compatibility depends on the selected backplane, connector arrangement, card guide configuration, power distribution, and rear I/O implementation.
The mechanical standards are particularly important in systems that must maintain interoperability with established Eurocard form factors:
- IEEE 1101.1 defines mechanical dimensions and related characteristics for Eurocard-based assemblies.
- IEEE 1101.10 addresses additional mechanical and electromagnetic compatibility provisions used in protected Eurocard environments.
- IEEE 1101.11 defines rear transition-module and related mechanical interface considerations.
A chassis designed for these environments must preserve more than nominal board height. Connector alignment, guide spacing, injector and extractor clearances, front-panel retention, rear module alignment, and the relationship between front and rear card positions all affect system reliability.
For this reason, Series 2345 configurations should be specified with the intended backplane and board population rather than treated as a universal empty enclosure. Vector’s backplane product range and chassis and system enclosure portfolio provide the relevant system context.
Dual-cage layout and rear I/O
The dual-cage arrangement separates the active front cards from their associated rear transition modules. This is useful when the system requires dense external connectivity but the front panels must remain organized around payload access, indicators, and card extraction.
Rear transition modules can carry:
- I/O connectors
- Signal breakouts
- Network and communications interfaces
- Control and monitoring connections
- Maintenance access points
- Cabling associated with individual front payload cards
Routing I/O through the rear cage keeps system cabling away from the front card extraction path. It also allows the front cards to remain installed while technicians work on external connections from the rear of the rack.
The 3U x 80 mm rear module depth provides a defined space for transition hardware and connectors while keeping the overall chassis depth to 11.65 inches. That depth is significant for rack integration because it limits the enclosure’s intrusion into the cabinet and leaves additional room for rear cable routing, rack clearances, and adjacent equipment.
Rear I/O design still requires configuration control. The transition module connector scheme must match the backplane pinout and the intended front card population. High-speed or tightly controlled interfaces may also require attention to signal integrity, grounding, shielding, connector selection, and cable bend radius.
Airflow from intake to exhaust
The Series 2345 uses a directed cooling path with front and side intake and top exhaust. This arrangement establishes a defined movement of air through the enclosure rather than relying only on incidental ventilation through perforated panels.
The airflow strategy addresses several practical requirements:
-
Front access to cooler intake air
Air entering from the front can pass across the card cage and backplane region, where board-level heat is typically concentrated. -
Side intake for additional flow area
Side intake openings increase available inlet area and can reduce the restriction presented by a narrow front panel or densely populated card cage. -
Top exhaust for heated air removal
Since heated air naturally rises, the top exhaust path supports removal of air after it has passed through the card and power regions. -
Serviceable filtration
Removable filters allow contamination control without requiring complete chassis disassembly. Filter loading must be included in the thermal design because increasing pressure drop reduces available airflow. -
Three hot-swap 12 VDC axial fans
The fan assembly provides forced air while allowing fan replacement without removing the entire chassis from service. Hot-swap capability is particularly useful in systems where maintenance must be performed with minimal disruption.
The specified operating temperature range is 0 to 50°C, with a non-operating range of -40 to 75°C. These values define the environmental range for the chassis configuration; they do not replace system-level thermal validation. Actual card temperature depends on board power, slot population, inlet temperature, fan condition, filter loading, airflow impedance, and the thermal characteristics of the installed backplane and modules.
For a completed system, airflow verification should be performed with the intended board population and representative loads. Empty-slot conditions can produce a different pressure and velocity profile from a fully populated system. The same applies to rear transition modules and installed cabling, which can obstruct exhaust or alter local flow.
Plug-in power and redundancy
The Series 2345 accepts plug-in power supplies measuring 3U x 8HP x 160 mm and using the PICMG 2.11 power-supply format. The chassis can accommodate one to three supply modules, depending on the required configuration.
This arrangement provides several power design options:
- A single supply for lower-complexity systems
- Two supplies for increased capacity or service flexibility
- Three supplies for systems requiring N+1 redundancy
In an N+1 configuration, the installed supply capacity is sized so that the system can continue operating after the loss of one supply module, subject to the load profile and the selected power architecture. The redundancy calculation must include steady-state demand, startup current, transient loads, derating, cooling conditions, and the voltage and current requirements of the installed backplane and cards.
PICMG 2.11 plug-in supplies also support a service model in which a failed module can be removed and replaced independently of the complete chassis assembly. This is preferable to integrating a fixed supply deep inside the enclosure when the system is deployed in a test rack, telemetry platform, medical instrument, or other equipment requiring controlled maintenance.
Power monitoring can be incorporated into the configuration to provide status information for supply operation and system-level fault handling. The monitoring implementation should be defined alongside the supply population, backplane power distribution, supervisory requirements, and external control interface.
Serviceability and configuration control
Serviceability is built into the Series 2345 architecture through replaceable fans, removable filters, plug-in power modules, front card access, and rear transition-module access. These features reduce the number of tasks that require complete system removal or extensive disassembly.
A disciplined service strategy should still document:
- Fan replacement procedures
- Filter inspection and replacement intervals
- Power-supply module compatibility
- Connector mating and extraction requirements
- ESD handling procedures
- Rear I/O cable identification
- Torque and retention requirements
- Configuration-specific slot assignments
For production systems, the chassis is one element of a larger controlled assembly. Backplane selection, front and rear panels, power supplies, fans, card guides, wiring, labeling, and firmware or monitoring interfaces should be tracked as a defined configuration.
Vector’s system-enclosure and documentation resources support this broader approach. Where required, complete box-build and system assembly can combine the enclosure, backplane, panels, power, cooling, and wiring into a test-ready system built to the customer’s defined configuration. This is relevant to legacy refreshes and fast-turn integrations, where reducing integration iterations and avoiding unnecessary re-spins are primary engineering objectives.
Application considerations
Series 2345 is suited to applications that require a compact 4U rackmount enclosure for vertical 3U cards, rear I/O, forced-air cooling, and serviceable modular power. Typical design reviews should evaluate:
- Required bus or fabric architecture
- Front card count and connector loading
- Rear transition-module population
- Board power and total thermal load
- Required supply capacity and redundancy
- Rack airflow direction and inlet temperature
- Filter maintenance access
- Rear cable clearance
- Environmental and flammability requirements
- Monitoring and fault-reporting interfaces
- Configuration control and traceability
The central design principle is to treat the chassis as part of the system architecture. Mechanical dimensions, airflow, power, backplane topology, rear I/O, and service access are interdependent. A successful implementation aligns these elements before hardware is released for production.
The Vector Series 2345 provides that foundation in a 4U, 19-inch EIA-310-D format: a 3U x 160 mm front card cage, a 3U x 80 mm rear transition-module cage, directed cooling, removable filtration, hot-swappable 12 VDC fans, and modular PICMG 2.11 power options. For vertical Eurocard systems, those decisions address the practical constraints that determine whether a chassis is merely compatible: or genuinely usable in a maintained production system.