NORIS A1-91 Series PCB Rack Modules

The NORIS A1-91 series comprises backplane rack modules designed for NORIS programmable logic controller systems. These PCB card holders provide mechanical support and electrical interconnection for CPU, I/O, and communication cards in a modular automation architecture. The series includes models A1-91-4, A1-91-5, A1-91-6, A1-91-7, and A1-91-8, each offering different slot counts and backplane features. They are typically used in industrial control cabinets for process automation, marine, and power generation applications.

Model Variants

A1-91-4: 4-slot backplane, passive, 5V/24V power distribution. A1-91-5: 5-slot with integrated bus termination. A1-91-6: 6-slot, supports extended addressing for larger I/O count. A1-91-7: 7-slot with redundant power supply connections. A1-91-8: 8-slot main rack for high-density applications. All modules are 19-inch rack mountable (3U height) with DIN 41494 compatibility. They feature a high-quality FR4 PCB with gold-plated card edge connectors for reliable signal transfer. The backplane provides a passive parallel bus for data, address, and control signals between modules. Power supply connections are via screw terminals on the backplane.

Key Features

• 19-inch rack mountable (3U, 133.5mm height)

• Slot counts: 4,5,6,7,8 depending on model

• Passive backplane design for high reliability

• Eurocard form factor (100mm x 160mm cards)

• Power distribution: 5V DC (up to 20A), 24V DC (up to 10A) via backplane

• Integral card guides and ESD protection

• Gold-plated DIN 41612 connectors (32-pin or 64-pin)

• Status LEDs for power good per slot

• Operating temperature 0-60°C

Mechanical Construction

The rack consists of a metal chassis (aluminum or steel) that holds the backplane PCB and provides card guides for up to the specified number of modules. The backplane is a multi-layer PCB with low-inductance power traces. Each slot has a DIN 41612 connector (type C, 96 pins) that mates with NORIS I/O and CPU cards. The rack includes a front panel with slots for mounting cards via faceplates. Power entry is via screw terminal blocks or a backplane power connector. The rack is designed for horizontal mounting in a 19-inch cabinet. Depth is approximately 220mm including card clearance. Weight ranges from 1.5kg (4-slot) to 3kg (8-slot).

Bus Architecture

The A1-91 backplane implements a proprietary NORIS bus, typically with 16-bit data and 24-bit address lines, plus control signals such as IORQ, MEMRQ, interrupt lines, and bus arbitration. Some models include an auxiliary serial bus for remote I/O. The backplane is passive, meaning no active logic; all bus control is performed by the CPU card. Termination resistors are provided on the last slot for signal integrity, especially on longer racks (7 or 8 slots). For systems with more than 8 slots, multiple racks can be connected via extension cables using a bus converter module.

Compatible Modules

The A1-91 series racks accept NORIS CPU modules (e.g., A1-CPUxx), digital I/O (A1-DI16, A1-DO16), analog input (A1-AI8, A1-AI4), analog output (A1-AO4), and communication modules (A1-COM, A1-ETH). Also compatible are third-party Eurocard-sized modules that adhere to the same pinout and mechanical dimensions (subject to verification). Hot-swapping is not supported; power must be off when inserting or removing cards.

Power Supply Integration

The backplane includes separate power rails for 5V logic and 24V field power. A power supply module (e.g., NORIS N1-PS) can be mounted in a dedicated slot or externally connected via the backplane terminals. Each slot is fused (resettable PTC) for overcurrent protection. The backplane also distributes a battery backup line for CPU RAM retention. LEDs on the front panel indicate +5V, +24V, and battery status.

Applications

These racks are used in NORIS automation systems found in ship automation (engine room monitoring), power plant control, water treatment, and industrial machinery. The modular design allows scaling from small 4-slot systems to large 8-slot configurations. The A1-91 series is suitable for both OEM and replacement installations.

Installation and Maintenance

Install the rack into a 19-inch cabinet using four M6 screws. Connect the main power supply (24V DC) to the backplane terminals. For grounding, a separate stud is provided for PE. Insert cards by aligning them with the card guides, press firmly into the DIN connector, and secure with front panel screws. The backplane requires no periodic maintenance. If a slot fails, replace the entire rack; individual slot repair is not practical.

Environmental and Certifications

The A1-91 racks are certified to CE, DNV (for marine), and UL (for industrial control). Operating temperature: 0°C to 60°C; storage -20°C to 70°C. Humidity: 5-95% non-condensing. Vibration tolerance 2g (10-55 Hz). The PCB is coated with conformal coating for moisture and dust resistance.

Conclusion

The NORIS A1-91 series PCB rack modules provide a robust and scalable backplane for NORIS PLC systems. With multiple slot options, they accommodate a wide range of I/O and CPU cards, making them suitable for control applications from small standalone units to larger distributed systems.