PLCs, Power Supplies & Others

The 6ES5490-7LB21 front connector routes field wiring into SIMATIC S5 I/O modules. Siemens builds this connector for legacy cabinets that need dependable terminal access. It plugs into the module front and gives technicians a removable wiring point during service.

Terminal Count and Wiring Interface

The connector offers 20 screw terminals, and each terminal accepts conductors from 0.5 mm² to 2.5 mm². A keyed housing mates with the module front port and blocks reversed insertion. Captive clamping plates hold each conductor firmly under vibration. Moreover, numbered terminal markings speed up conductor identification during checkout.

Physical Dimensions and Construction

The connector measures 85 mm in length, 40 mm in width, and 25 mm in depth. It weighs approximately 0.1 kg, so it adds minimal load to the module front. The housing uses flame-retardant plastic that meets standard S5 enclosure ratings. Gold-plated contact pins resist corrosion in humid plant rooms.

Installation and Wiring Notes

Technicians seat the 6ES5490-7LB21 into the module front port until the latch clicks. Field conductors land on the numbered screw terminals and tighten to the rated torque. Crews can remove the connector as one piece during module swaps. Therefore, maintenance work moves faster and rewiring errors drop.

Why This Connector Supports Legacy S5 Retrofits

Maintenance teams select the 6ES5490-7LB21 for its 20-terminal capacity and removable design. The keyed housing prevents reversed insertion during rushed maintenance work. Gold-plated pins hold up in humid and corrosive plant rooms. This front connector serves plants that keep S5 systems running for spare-part continuity.

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