NORIS A1-91 Series PCB Rack Module for PLC Systems

The NORIS A1-91 is a family of PCB rack modules (carte rack) designed for use in NORIS programmable logic controllers and industrial automation racks. These boards serve as the physical backplane that interconnects power supply, CPU, I/O, and communication modules. Variants A1-91-4, A1-91-5, A1-91-6, and A1-91-7 differ primarily in the number of slots and mounting configurations.

Model Variants and Slot Counts

Technical Specifications

All A1-91 modules are manufactured on FR4 epoxy glass PCB with 2 oz copper traces for high current capacity. Key electrical characteristics:

• Rated current per slot: up to 2A (logic) and 1A for auxiliary power

• Bus voltage: +5VDC, +24VDC (field power)

• Maximum total backplane current: 8A (A1-91-7) with adequate cooling

• Connector type: DIN 41612 96-pin female for each slot

• Operating temperature: -10°C to +60°C

• Isolation between logic and field sides: 1500VAC for 1 minute

Mechanical Dimensions

A1-91-4: 200mm x 160mm; A1-91-5: 250mm x 160mm; A1-91-6: 300mm x 160mm; A1-91-7: 350mm x 160mm. All boards have 4mm mounting holes at corners for secure installation into control cabinets. Thickness is 1.6mm.

Signal Assignments

Each slot follows the NORIS standard pinout: rows A, B, C. Row A carries +5V and ground; row B carries data lines D0-D15; row C carries address lines A0-A10 and control signals (IOW, IOR, RESET, etc.). The A1-91 series also includes a separate connector for external 24V field power distribution.

Application and Usage

The A1-91 rack modules are fundamental to building scalable NORIS PLC systems. They allow mixing of digital input/output cards, analog modules, and specialized function cards. Proper grounding and bus termination resistors (included on the board) ensure signal integrity for high-speed communication with the CPU module.

Environmental Compliance

RoHS compliant (lead-free solder and component finishes). Conformal coating is optional (specify when ordering). The PCBs withstand vibration up to 5g (10-150Hz) and shock of 15g/11ms half-sine.

Installation Notes

When installing modules into A1-91 rack, always power off the system first. Align the card guide, then firmly press until the locking tabs click. Verify that all slot addresses are uniquely assigned using the DIP switches on individual I/O cards. Maximum cable length to remote racks is 10 meters using shielded ribbon cables.