The 6ES7194-2LH20-0AC0 is a 2-meter shielded PROFINET bus cable for SIMATIC ET 200AL with an M8 straight plug (4-pole) at one end and open wire leads at the other. The green PVC jacket and 2Y(ST)CY dual-shield construction (aluminum foil plus tinned copper braid) carry 100-Mbps PROFINET from a field-terminated connection into the ET 200AL bus daisy-chain.

When do I need the open-end bus cable?

Two main scenarios. First-module entry: the PROFINET signal arrives at the ET 200AL island through a standard industrial Ethernet cable (RJ45 or M12) from a switch or upstream controller, but the first ET 200AL module has an M8 bus input port. This cable bridges that gap—M8 plug into the module, open leads landed on the incoming Ethernet cable's punch-down or screw terminals inside a junction box. Custom topology: the standard plug-and-socket cables force a linear daisy-chain, but the physical layout of the modules requires a different routing. The open-end cable lets you trim to exact length or route through conduit that a pre-terminated plug will not pass through. The shield drain wire must be terminated to ground at the field end for the dual shield to be effective.

Green bus, open end—the dual shield still matters.

Even with open wires at one end, this is a shielded PROFINET cable. Terminate the shield drain wire properly at the field end—do not leave it floating. An ungrounded shield acts as an antenna rather than a barrier, coupling EMI directly into the data pairs. The 2Y(ST)CY cable has both an aluminum foil wrap and a tinned copper braid; the braid is the drain connection point. Strip back enough jacket to expose the braid, connect it to the ground terminal at the junction box, and keep the unshielded tail as short as possible.