Non-Contact Capacitive Height Sensor Control Unit for CNC Plasma and Oxy Fuel Cutters

The CAP-04 is a professional-grade, non-contact sensing solution engineered for high-demand CNC Plasma and Oxy-Fuel cutting environments. Unlike traditional Ohmic sensors that require a physical electrical circuit to be completed through the torch shield and the workpiece, the CAP-04 utilizes advanced capacitive field technology. This allows for precise height sensing on materials where traditional methods fail—such as heavily rusted, painted, or non-conductive coated metals.

Advanced Sensing Technology & Performance
By monitoring the capacitance between the sensing ring and the workplate, the unit detects surface proximity without ever touching the material. This true non-contact operation eliminates the "touch-and-retract" cycle, significantly reducing cycle times and preventing torch crashes on warped or flexible thin-gauge sheets. The unit allows for fine-tuned adjustments of both the External Height (Initial Sensing) and the Internal Gap Window. This "window" logic ensures the torch stays within a specific voltage/height band for smoother Z-axis response and superior edge quality. Furthermore, the built-in anti-dive logic prevents the torch from diving during corners, lead-ins, or slowdown zones where arc voltage typically fluctuates, providing a stable height reference independent of the plasma arc.

Industrial Build & Safety Features
Housed in a sealed, die-cast aluminum enclosure, the CAP-04 is built to withstand the "black dust" (iron oxide), sparks, and moisture common in industrial plasma shops with an IP65 and NEMA 4 rating. The dedicated ERROR output provides an automated safety net, instantly triggering a signal to your CNC controller if it detects a sensor disconnect, a short circuit from physical contact, or a general system fault. To assist the operator, a high-visibility 4-LED status array allows for troubleshooting at a glance, featuring dedicated indicators for UP and DOWN motion, TOUCH (indicating physical contact), and CABLE FAULT to signal a short or open circuit in the sensing lead.

Integration & Control Logic
Unlike "bang-bang" controllers that only offer full-on/full-off signals, the CAP-04 can provide Proportional PWM. This allows for a variable duty ratio based on the torch's distance from the target, resulting in a significantly faster and more fluid Z-axis response when paired with an H-Bridge-9 driver. The unit is designed for seamless integration using industrial-standard 24VDC input power and supports logic signals up to 24V for UP, DOWN, and ERROR outputs. For more sophisticated CNC logic, it features 0-10V connection points for analog feedback and utilizes robust, noise-shielded Ethernet-style (RJ45) connectors for the sensor head.

Technical Specifications & Compatibility
The system is compatible with a wide range of materials, including steel, stainless, and aluminum—even when rusted or painted. It operates on a 24VDC power supply within a rugged, die-cast aluminum housing and provides both isolated digital outputs and proportional PWM. The interface supports 0-10V analog and 24V logic signals, utilizing a replaceable high-temperature sensing ring as the primary sensing element. Designed for surface mounting or direct integration into CNC4PC interface kits, it is a practical solution for real-world plasma table installations.