The WEBER C5S is a digital process controller for fixtured and handheld screwdriving spindles in automated assembly stations. It fills the gap between basic screwdriver power supplies and high-end controllers with direct torque transducers — using current-based (indirect) torque measurement to eliminate the cost and complexity of an inline torque sensor while still providing configurable tightening programs and digital I/O for line integration.

How does current-based torque measurement work?

The C5S monitors the EC servo motor's current draw, which is proportional to the torque applied at the screwdriver bit. While less accurate than direct torque transducer measurement — material density variations in wood or plastic can shift the current-torque relationship — it is entirely adequate for fastening applications where the acceptable torque window is wide (e.g., furniture hinge screws, plastic housing assembly) and the cost and fragility of a torque sensor are unjustified. Active electronic motor braking (~20 ms) stops the spindle promptly when the target current threshold is reached, preventing overshoot.

What tightening strategies and programs are available?

Seven selectable process cycles cover the common screwdriving scenarios: torque-controlled tightening to a current threshold, depth-controlled tightening to a position limit, torque+depth combination, and reversing/loosening cycles. Fifteen storable programs are selected by binary-coded digital inputs, enabling a single C5S to serve multiple assembly stations or product variants on the same line. The internal servo amplifier (SIEB & MEYER SD4S) supports CANopen for integration with higher-level sequence controllers such as WEBER's C15 and CU30 systems that manage spindle positioning, screw feeding, and peripheral device coordination.