Siemens 6ES5490-7LB21 Front Connector

The 6ES5490-7LB21 serves as a front connector for Siemens SIMATIC S5 modules. This unit provides convenient field wiring access for I/O signals. Its rectangular frame measures 156 millimeters in width. The connector height reaches 118 millimeters exactly. Depth stays at 62 millimeters. You will find this unit weighs approximately 0.32 kilograms. Therefore, installation requires clipping the connector onto the front of an S5 module. One 20-position screw terminal block handles all field wiring connections.

Physical Layout and Connectors

The screw terminal block accepts wires up to 14 AWG gauge. Each terminal uses a rising cage clamp for secure wire retention. A 20-pin male connector plugs directly into the S5 module face. Two locking levers secure the connector firmly to the module. You can label each terminal using the included write-on strips.

Technical Specifications

Parameter	Specification
Connector Width	156 mm
Connector Height	118 mm
Connector Depth	62 mm
Unit Weight	0.32 kg
Terminal Points	20 (screw clamp)
Wire Gauge	24 to 14 AWG (stranded/solid)
Mating Cycles	200 insertions minimum
Contact Material	Tin-plated brass
Current Rating	2A per terminal
Voltage Rating	250V AC / 48V DC
Component Total	24 discrete parts
Internal Energy Storage	None (0 µF)
Housing Material	Polycarbonate, UL 94 V-0
Operating Temperature	-25°C to +70°C

Internal Design and Construction

The 6ES5490-7LB21 contains exactly 24 discrete passive components inside. A simple PCB routes each terminal to its corresponding connector pin. The board uses no capacitors or energy storage devices. Gold-plated contact pins ensure reliable signal transmission over time. The screw clamps maintain constant pressure on each wire. This design eliminates the need for special crimping tools.

Operational Performance

This front connector attaches directly to any SIMATIC S5 I/O module. It transfers signals between field devices and the PLC module. Moreover, the unit supports both digital and analog signal types. You can terminate up to 20 individual field wires at one location. The screw clamps resist vibration better than spring terminals. Each clamp releases quickly for wire changes or rework. Consequently, you achieve fast and reliable field wiring terminations. Siemens designed this connector for S5 series compatibility. Its compact size saves space inside control cabinets.

In summary, the 6ES5490-7LB21 delivers efficient I/O connection capability. Use this connector for field wiring to S5 modules. It simplifies installation without special tools or training. Order this front connector for your Siemens SIMATIC S5 system.