CAPAC® Ca­pa­cit­ance Meas­ur­ing Sys­tem

Why CAPAC®?

The Zumbach CAPAC® delivers high-accuracy inline capacitance measurement for RF, CATV, data, and LAN cable production with solid or foamed insulation. Designed for extrusion line integration, it ensures continuous, real-time monitoring where capacitance is a critical quality and performance parameter. At its core, a precision measuring tube, connected to a dedicated processor that delivers a precisely controlled measurement signal, captures capacitance measurements instantly. The advanced signal processor, in combination with the measuring tube, ensures a very high signal-to-noise ratio, providing reliable measurement data for statistics, FFT/SRL and process control, enabling tighter manufacturing tolerances and improved product consistency.
With optional FFT analysis and SRL prediction up to 6.5 GHz, CAPAC® goes beyond standard measurement. It allows early detection of periodic defects, prediction of structural return loss, and proactive quality control, helping manufacturers reduce scrap, optimize performance, and ensure compliance with high-speed cable standards.

• High‑accuracy inline capacitance measurement: ±0.1 pF/m precision with 16‑bit resolution across wide ranges (up to 1800 pF/m) – ideal for coaxial, RF, and CAT type high‑speed data cable production.
• Advanced process insight with FFT analysis & SRL prediction: Detect periodic fluctuations early and predict structural return loss up to 6.5 GHz – directly on the extrusion line, at slow and high line speeds.
• Integrated pinhole detection: Identify insulation defects, holes, and bare spots in real time with adjustable sensitivity – preventing downstream failures or faulty product being shipped to the end customer.
• Flexible, integration‑ready system: Modular design with a range of measuring tube sizes and active electrode length, to best fit product diameter range and application. Processors are available with a range of interfaces (EtherNet TCP/IP, PROFINET, EtherNet/IP) – seamlessly connects to PLCs, SCADA, or Zumbach USYS® systems.

Proven per­form­ance world­wide

Zumbach CAPAC® capacitance measurement systems have been trusted in cable production lines worldwide for decades, with thousands of installations supporting applications from data and LAN cables to high-performance RF and CATV products. CAPAC® is designed for manufacturers requiring advanced inline quality control, going far beyond basic capacitance measurement. In combination with FFT-based process analysis and online SRL prediction up to 6.5 GHz, it enables early detection of process deviations and ensures consistent high-frequency cable performance.
Fully compatible with Zumbach USYS® processors, CAPAC® integrates seamlessly alongside ODAC® diameter gauges and other inline sensors, delivering complete process visibility, inline quality documentation, FFT/SRL, and closed-loop process control for modern cable extrusion lines.

Fre­quently asked ques­tions

What is the difference between the CAPAC® 10 mm and 50 mm measuring tubes?
The capacitance measuring tube with the 10 mm electrode provides higher longitudinal resolution whilst maintaining a low noise floor, making it ideal for detecting shorter, localized capacitance variations. The capacitance measuring tube with the 50 mm electrode offers a higher signal-to-noise ratio, ensuring reliable detection of fine capacitance fluctuations in data and LAN (CAT) communication cables.

What is SRL and why does it matter?
SRL (Structural Return Loss) is the most widely used method for predicting the transmission quality of the final cable  as a function of the signal frequencies it will carry. CAPAC® with the USYS FFT/SRL option predicts SRL up to 6.5 GHz online during production – giving manufacturers early warning of potential transmission performance issues during the extrusion of the wire.

What does the Pinhole function detect?
It detects holes and bare patches (areas without insulation) in the cable insulation during production. Sensitivity is adjustable. This provides an additional layer of defect detection alongside spark testing, catching faults that may not trigger a spark tester but could affect electrical performance.

Which measuring tube size do I need?
The tube inner diameter defines the product clearance for the wire/cable outer diameter: MR.12 for diameters up to 8 mm, MR.36 for up to 24 mm, MR.68 for up to 45 mm. Active length (10 mm or 50 mm) is selected based on the application – wire/cable type, required resolution, and whether FFT/SRL analysis is needed.

Can CAPAC® integrate with our existing line control system?
Yes. The electronics unit supports RS-232/422/485, EtherNet TCP/IP, PROFINET, and EtherNet/IP host interfaces. It also features an integrated webserver, enabling configuration and monitoring via any standard web browser with no additional software required. The configuration with the Zumbach J-interface allows for direct connection to USYS® 20/200/Touch/IPCe processors. 

Can CAPAC® be used as a fault detector in jacket lines?
Yes. CAPAC® can be deployed as a fault detector in cable jacket lines, detecting insulation faults with adjustable sensitivity. This makes it a versatile addition to lines where multiple quality parameters need to be monitored simultaneously.

Does CAPAC® support closed-loop control?
Absolutely. When connected to a USYS® processor or PLC, CAPAC® data can be used to automatically adjust extruder speed, haul off, or other process parameters, to keep the capacitance of the insulated wire within tight tolerances.