A 15-meter M8 straight-plug to open-end cable in the distinctive green jacket that marks it as an ET 200AL PROFINET bus data cable. The straight M8 plug connects to an I/O block bus port; the open end terminates at a PROFINET switch, an upstream ET 200AL node, or a field-mountable M8 bulkhead connector. Shielded construction protects PROFINET frames from EMI in industrial machine environments.

Green vs. gray—why the color discipline matters

ET 200AL uses jacket color to prevent one of the costliest field-wiring mistakes: plugging 24VDC power into a PROFINET port. Green cables carry bus data (PROFINET RT/IRT frames between nodes). Gray cables carry 24VDC power (supply voltage for the I/O electronics and connected sensors). The 4-pole M8 connector is physically identical across both—only the color prevents a commissioning error that can damage Ethernet PHYs on the controller side. Never substitute a gray cable for a green one or vice versa.

How do I terminate the open end for PROFINET?

The 4 conductors follow the standard M8 D-coded PROFINET pinout: pin 1 = TD+, pin 2 = RD+, pin 3 = TD-, pin 4 = RD-. At the cabinet end, land these on an RJ45 field-attachable connector or patch panel, maintaining the twisted-pair pairing (1/3 and 2/4). Connect the shield drain wire to functional earth at the cabinet entry point. Keep the untwisted section under 13mm to preserve the 100Ω differential impedance.