Detailed Description
What Is a PROFINET Industrial Ethernet Cable?
PROFINET is an industrial Ethernet protocol developed by Siemens and maintained by PROFIBUS & PROFINET International (PI). Unlike office Ethernet — where a network outage means a few seconds of inconvenience — PROFINET on a factory machine carries the real-time data that keeps servo drives synchronized, safety circuits active, and the production line running. The cable that carries those signals must meet performance requirements that an office-grade patch cable does not.
A PROFINET cable is a 4-pair shielded twisted pair (100 Ω, CAT5e or better) with specific additional requirements:
- Double shielding (SFTP) — foil per pair plus overall braid. In a control cabinet or on a machine frame, the cable shares space with VFD motor power cables, contactors, and welding equipment. Single-shield office cable does not provide sufficient EMI protection
- Green PUR jacket — the green colour is the de facto standard for PROFINET cabling worldwide. When a maintenance electrician sees a green data cable on a machine, they know it is PROFINET — not a generic Ethernet cable that may have been installed for an IP camera or office LAN
- Flex rating for machine duty — PROFINET cables are installed on moving machine sections, in drag chains, and on robot arms. The Type B (flexible) and Type C (continuous flex) specifications define the mechanical performance
PROFINET Cable Types — A, B, and C
| Type | Application | Conductor | Minimum Bend Radius | Jacket | Typical Location |
|---|---|---|---|---|---|
| Type A | Fixed installation | AWG 22 solid | 8× OD | PVC or PUR | Control cabinet, cable tray, fixed trunking |
| Type B | Flexible installation | AWG 22 stranded | 12× OD | PUR | Machine frame, occasional movement, articulated arm |
| Type C | Continuous flex / drag chain | AWG 26 stranded | 15× OD | PUR | Drag chain, robot arm, linear transfer axis, pick-and-place |
On a typical production machine, all three types may be used: Type A in the control cabinet from the PROFINET switch to the cabinet wall, Type B from the cabinet to the drag chain entry point, and Type C through the drag chain to the moving I/O block or drive.
Application Analysis
- Servo drive networking: PROFINET IRT (Isochronous Real Time) connects the motion controller to multiple servo drives with cycle times as low as 250 µs — the cable's delay skew must be tightly controlled so that all four pairs deliver their data within the IRT time window
- Distributed I/O on the machine: A PROFINET Type C cable in the drag chain connects the control cabinet switch to the remote I/O block on the moving pallet or slide — carrying 100 Mbps of sensor inputs, actuator outputs, and safety data on one thin, flexible cable
- PROFIsafe safety communication: Safety-rated signals (E-stop, light curtain, safety door) are carried on the same PROFINET cable as standard automation data — eliminating the need for a separate hardwired safety circuit cable. The cable's shield integrity and bit error rate directly affect safety system availability
- Vision and quality inspection: GigE Vision cameras on the production line connect to the vision processor via PROFINET-compatible Ethernet cable — the double shielding prevents motor noise from corrupting high-resolution inspection images
Why Choose Yichi for PROFINET Cables
- Tested to PROFINET PI cabling guidelines — not just CAT5e: A CAT5e cable passes the TIA/EIA electrical tests. A PROFINET cable passes those plus the PROFINET-specific requirements: green jacket, double shielding, mechanical flex rating, and connector compatibility
- Double-shielded construction as standard: Foil per pair (100%) + overall braid (≥85%) — no single-shield compromise that risks communication faults in electrically noisy machine environments
- Type A, B, and C from one manufacturer: Specify the mechanical duty at each point in the machine — fixed, flexible, or continuous flex — and receive the correct cable type with consistent electrical performance across all three
- 100% factory electrical test with NEXT and return loss: Every production length is tested for wiremap, length, insertion loss, near-end crosstalk (NEXT), and return loss — the full set of CAT5e parameters that determine PROFINET signal quality
- Factory-direct for machine builder projects: OEM machine builders wiring hundreds of machines per year with PROFINET — Yichi provides consistent cable quality, full test data per production batch, and competitive volume pricing