Siemens 6ES5491-0LC11 PLC Module | 16 x 24V DC Digital Inputs

The 6ES5491-0LC11 functions as a digital input module for Siemens SIMATIC S5 systems. This unit reads discrete signals from field sensors and pushbuttons. Its rectangular frame measures 232 millimeters in width. The module height reaches 210 millimeters exactly. Depth stays at 155 millimeters. You will find this unit weighs approximately 0.85 kilograms. Therefore, installation requires sliding the module into a standard S5 rack slot. One 24-pin removable terminal block handles all field wiring connections.

Physical Layout and Connectors

The terminal block accepts wires up to 16 AWG gauge. Each channel uses separate terminals for signal and common return paths. A green LED illuminates when each input channel receives a valid signal. Two guide rails secure the module firmly in the rack. You can remove the terminal block without disconnecting the module from the backplane.

Technical Specifications

Parameter	Specification
Module Width	232 mm
Module Height	210 mm
Module Depth	155 mm
Unit Weight	0.85 kg
Input Channels	16 (24V DC sinking)
Terminal Block	1 x 24-pin removable (16 AWG)
Component Total	178 discrete parts
Input Voltage Range	20.4–28.8V DC
Input Current	7 mA per channel (typical)
On-State Threshold	>15V DC
Off-State Threshold	<5V DC
Response Time	3 ms (on/off)
Input Isolation	1500V (optocoupler)
Internal Energy Storage	470 µF capacitor bank
Operating Temperature	0°C to +55°C

Internal Design and Energy Storage

The 6ES5491-0LC11 contains exactly 178 discrete components onboard. A 470 microfarad capacitor bank filters the internal logic supply voltage. Sixteen optocouplers provide complete isolation for every input channel. Each optocoupler withstands 1500 volts between field and logic sides. A shift register chip serializes the input data for backplane transmission. The module also includes LED drivers for the 16 status indicators.

Operational Performance

This digital input module connects directly to pushbuttons, limit switches, and proximity sensors. It accepts input voltages from 20.4 to 28.8 volts DC. Moreover, the module filters electrical noise with built-in debounce circuitry. You can mix 24V DC sinking sensors from different manufacturers without issues. The unit reports input state changes to the processor every scan cycle. Sixteen green LEDs show real-time input status across the front panel. Consequently, you achieve reliable signal acquisition for S5 systems. Siemens designed this module for SIMATIC S5 automation platforms. Its conformal coating protects against humidity and light contamination.

In summary, the 6ES5491-0LC11 delivers dependable digital input functionality. Use this module for factory automation or conveyor systems. It provides 16 input points in a single slot design. Order this PLC module for your Siemens S5 system expansion.