Accurate high-cycle clutch-brake positioning control

Force Control Industries presents the CLPC Control Model LC, which provides precise positioning on indexing applications when coupled with a Posidyne clutch brake. Designed to control high cycle count applications where the scan times of PLCs are too slow for accurate positioning, the CLPC-LC includes the CLPC control unit, and a position encoder mounted on the clutch brake output shaft to ensure precision. This compact closed-loop position control system operates from 85 to 264 Vac, 47 to 63 Hz, single-phase input power, and requires no calibration so it is always ready. It automatically detects jams (no encoder rotation) before reaching the desired stop position and disengages the clutch. The compact design allows door mounting or panel mounting. Eleven internally tested functions with error codes with descriptions are displayed to identify faults. A watchdog timer, adjustable from 100 milliseconds to 1 minute will disengage the clutch if timed out before reaching the desired stop position – thus protecting against jams which stop or slow down the drive.

The Force Control CLPC-LC is suitable for high cycle count applications which require precise positioning such as fiberglass choppers, case packers, assembly line part conveyors, Ferris wheel turnover systems, press feeder feed-to-length applications, part cut-off cut-to-length applications, and more.

How it works
The optical encoder mounted on the clutch brake output shaft counts the pulses back to the CLPC control. The control is programmed via push buttons on the face of the control to index (when given a start signal) the desired number of pulses for a complete index. Because a brake will not stop the drive instantly, the brake must be engaged before the stop position, allowing time for the drive to decelerate to stop (called the “trigger point”). When initially starting the drive, the index distance is programmed into the control, and the trigger point is set automatically. As the drive is indexed, if the stop is out of position, the trigger point automatically adjusts until the stop is in location. This typically works on a 5-index algorithm to avoid “hunting.”

When the correct number of pulses is reached (the trigger point) the control will signal the brake to engage and release the clutch. The stop position can be adjusted by using the manual adjust setting to adjust the stop position one pulse at a time to the desired position. This then becomes the stop or home position. When the brake signal is received and the brake is engaged it will decal to top within so many pulses. In operation, any variation in stopping due to temperature change, load change, or torque change will cause the top to be out of position. The trigger point will then be adjusted to compensate for the error. This is done on a 5-count algorithm to avoid “hunting.” The result is the trigger point continually adjusts itself to maintain an accurate stopping position.

For more information, visit https://www.forcecontrol.com/products/brakes/clpc/.