The Atlas Copco 8433056445 is an I/O expander module, also known as the Error Proofing module (FNOB), designed to augment the digital input/output capabilities of Atlas Copco tightening controllers, such as the Power Focus and Tensor series. This module adds a dedicated set of isolated digital I/O points that can be used for error‑proofing applications—for example, verifying that a part is correctly positioned, detecting the presence of a fastener, or interfacing with operator guidance lights and buttons. By providing additional I/O, the module enables more sophisticated quality assurance and assembly verification without requiring a separate PLC.
The FNOB module connects to the host controller via a high‑speed serial interface (SPI or CAN), automatically recognized by the controller’s firmware. It offers a combination of inputs and outputs that are configurable for various signal types. The module is housed in a compact plastic enclosure designed for DIN‑rail mounting, with pluggable terminal blocks for easy wiring. LED indicators on the front provide clear status for each channel.
Supply Voltage: 24 VDC (derived from controller)
Digital Inputs: 8 isolated, 24 VDC, sink/source selectable
Digital Outputs: 8 solid‑state, 24 VDC, 0.5 A per channel
Input Impedance: 3.5 kΩ
Output Protection: Short‑circuit and overcurrent protected
Response Time: < 1 ms
Interface: SPI (dedicated cable to controller)
Power Consumption: 2 W (typical)
Operating Temperature: 0 °C to +55 °C
Protection: IP20
Dimensions: 105 x 75 x 45 mm
Mounting is on a standard 35 mm DIN‑rail. The module connects to the controller using a supplied ribbon cable. Configuration is performed via the controller’s software (ToolsTalk), where each channel can be assigned a specific function—e.g., start signal, part‑present sensor, OK/NOK indicator, or interlock. The module’s address is automatically assigned, but can be manually set for multi‑module systems.
Typical use cases include: verifying that a component is correctly loaded before tightening, checking that the correct torque socket is installed, interfacing with a barcode reader to ensure the right job, controlling a stack light to guide the operator, and enabling a protective door interlock. The module can also be used to connect external push‑buttons for manual start or abort.
This I/O expander is compatible with all current Atlas Copco controllers that support the FNOB expansion: PF3000, PF4000, PF6000, TC‑4000, and Tensor S4/S7 series. Multiple modules can be cascaded to add up to 64 additional I/O points.
Each input has a green LED that illuminates when the input is active; each output has a yellow LED when energized. The controller can read the module’s internal diagnostic data, including short‑circuit detection and over‑temperature alerts.
By adding dedicated I/O, the FNOB module reduces the complexity of external wiring and eliminates the need for a separate PLC for simple logic. It improves cycle times by reducing communication overhead, and enhances safety by providing direct interlocking.
No routine maintenance required. The module is designed for long‑life operation with no moving parts.
The Atlas Copco 8433056445 I/O expander error‑proofing module is a cost‑effective, easy‑to‑integrate solution for adding quality assurance I/O to tightening systems, enhancing process reliability and operator guidance.



