Precision controller

Manufacturing Engineering, Jul 2000

For better performance in heavyduty, high-cycle-rate indexing operations, Force Control Industries, (Fairfield, OIT) offers a unit that combines an oilshear clutch/brake with a closed-loop positioning control.

It is said to provide servo-like accuracy without servo complexity, and beat PLCs on speed, simplicity, and cost.

The unit reportedly has a 100 msecond indexing capability, cycle rates to 600 cpm, and takes torque up to 88,000 lb-in (9944 N*m). The control has a touch-pad input with 16 character, two-line display. Setting the control engages the clutch for the desired number of pulses, then engages the brake to stop in the required position.

The control can have up to four limit switch outputs to trigger other machine functions. It can also be programmed for up to eight index setpoints for quick production changeover.

A fault detection circuit monitors up to 11 functions, and displays error code when a fault is identified. Stall detection senses jams, then stops the drive to prevent damage.

The oil-shear design minimizes torque fade for excellent repeatability. To ensure accuracy, the control compensates for changes in speed, dynamic load, air pressure, bearing friction, and environmental conditions. Circle 325.