Valmet 542852‑3A Slot Rack Chassis Module – Industrial Subrack

The Valmet 542852‑3A (also known as 3‑542852‑1A) is a rugged slot rack chassis module designed to house plug‑in electronic boards in industrial control cabinets. This enclosure provides mechanical support, EMC shielding, and guided slots for up to 12 modules (depending on configuration). It is a fundamental building block for Valmet DNA and Metso I/O systems, ensuring secure mounting and reliable operation in harsh environments.

Mechanical Construction

The chassis is constructed from 2 mm thick galvanized steel with a powder‑coated finish for corrosion resistance. It features a standard 19‑inch rack mounting width and a height of 6U (266 mm). The depth is 160 mm, accommodating Eurocard‑format boards. The unit includes top and bottom ventilation louvers and an optional fan tray for forced air cooling. Guide rails are fitted with anti‑vibration clips to hold modules securely.

Slot Configuration and Backplane Integration

The chassis can accommodate up to 12 slots, each with a 96‑pin DIN connector for backplane connection. The backplane (sold separately) provides the bus and power distribution. The chassis includes rear openings for cable entry and a removable rear panel for easy access. The module also has provisions for mounting a power supply unit (PSU) at the rear, with a dedicated cutout.

EMC Shielding and Grounding

The chassis is designed to provide effective EMC shielding with a grounding stud on the rear frame. A finger‑stock gasket around the front ensures a low‑impedance connection to the rack. All exposed metal parts are grounded to the protective earth terminal. The unit complies with EN 61000‑6‑2 and EN 61000‑6‑4 for industrial environments.

Cooling and Thermal Management

Natural convection cooling is sufficient for up to 100 W of heat dissipation. For higher loads, an optional fan module can be installed on the top. The chassis includes temperature sensors that can be connected to the system for overtemperature alarm. Airflow is directed from the bottom to the top, with baffles to ensure even distribution across the boards.

Dimensions and Mounting

Width 482.6 mm (19 inches), height 266 mm (6U), depth 160 mm. Weight is approximately 5 kg. It can be mounted in a standard 19‑inch rack using four M6 screws on the front flanges. For earthquake‑prone areas, additional rear support brackets are available.

Environmental Specifications

Operating temperature: 0 °C to +55 °C (with fan) or 0 °C to +45 °C (natural convection). Storage: ‑40 °C to +85 °C. Humidity: 5‑95 % non‑condensing. Protection class IP20 (front) and IP10 (rear when closed).

Installation and Cable Management

Install the chassis into the rack, securing it with screws. Insert the backplane and power supply. Route cables through the rear entry points, using the provided cable ties and strain relief bars. The front panels of inserted modules provide additional labeling for field wiring.

Applications

This chassis is used in all Valvet automation systems, housing CPU, I/O, and communication modules. It is found in control rooms and local cabinets throughout pulp, paper, and process industries.

Maintenance and Spares

Periodic cleaning of air filters (if fitted) and checking fan operation is recommended. The chassis itself is durable; if damaged, replacement is straightforward. Spare guide rails and hardware are available.

Conclusion

The Valmet 542852‑3A slot rack chassis provides a robust, standardized housing for modular automation boards, ensuring reliable operation and easy maintenance in industrial control systems.