PID Speed Control: Winch Systems and the PDS
Surface preparation and coating quality are speed problems. Travel too fast and coverage thins. Too slow and material piles up. CTX Automation builds closed-loop speed control that holds motion steady regardless of load, from a 350-foot stack winch to a portable coating-lance drive.
The winch in operation at the top of the stack.
Blast pot and hoses on the platform, with the control station.
Encoder on the winch line for position and speed feedback.
The winch that holds its speed
A company specializing in tall and difficult-to-access structures contacted us about blasting and coating the inside of a stack over 350 feet tall and 6 feet in diameter, without an operator inside. Our engineering team designed a PID-controlled winch that suspends the blasting and coating tools inside the stack and moves them at precise, programmable work speeds.
Load on a winch line is never constant. Hose weight changes with height, wind loads the platform, operators shift. The controller measures actual speed continuously and trims the drive to hold setpoint through every disturbance, turning a variable-load lift into a constant-speed pass with a consistent blast profile and coating thickness.
The Portable Drive System
The same control discipline is packaged in the PDS, the Clemtex Portable Drive System: a cart-and-track drive that carries an I.D. coating lance into a tube and retracts it at a computed speed. The operator enters the tube's inside diameter, length and end allowances along with the target dry-film thickness. The PLC derives the retraction speed from the measured coating flow rate and holds it closed-loop, so film thickness comes from the recipe rather than the operator's hand.
The PDS brings repeatable travel speed to work that cannot justify a permanent installation, and it is delivered with the same recipe, user and alarm screens as our fixed lines.
PDS control screen: tube data in, flow setpoint and DFT, lance position and speed out.
Why tuning is the difference
Any drive can turn at a speed. Holding that speed through disturbances without oscillating is the engineering. Our controllers are tuned against the real dynamics of the machine, including drive ramp rates, load inertia and measurement filtering, with anti-windup so a saturated drive recovers cleanly instead of overshooting. The same technology carries across our motion control work: variable frequency drives, servo systems, encoder feedback and limit switching, wherever a machine has to move exactly as told.
Have a machine that has to move exactly as told?
Tell us about the load. We will hold the speed.
Get in Touch (713) 672-8251