Siemens 6ES5488-3LU21 Digital I/O Card

Compact Mixed I/O for S5-135U/155U Systems

The Siemens 6ES5488-3LU21 digital input/output card combines 32 inputs and 32 outputs in a single module. This card saves valuable rack space by eliminating separate input and output modules. Medium to large control systems benefit from this efficient space-saving design.

I/O Specifications and Electrical Ratings

This digital I/O card provides 32 sinking inputs and 32 sourcing outputs in one compact unit. The inputs accept 24 V DC signals with a nominal current of 7 mA per channel. Each output switches up to 0.5 A at 24 V DC with short-circuit protection. Furthermore, the card includes optical isolation of 1500 V AC between the field signals and the backplane.

Parameter	Specification
Brand	Siemens
Model	6ES5488-3LU21
Digital Inputs	32 (sinking, 24 V DC)
Digital Outputs	32 (sourcing, 24 V DC, 0.5 A)
Input Current	7 mA per channel
Output Current	0.5 A per channel
Isolation Voltage	1500 V AC
Dimensions (W x H x D)	50 mm x 125 mm x 118 mm
Weight	0.45 kg
Power Consumption	5 V DC at 350 mA
Compatible CPUs	S5-135U, S5-155U
Operating Temperature	0°C to 55°C

Protection and Diagnostic Features

The Siemens 6ES5488-3LU21 incorporates comprehensive protection mechanisms for reliable operation. Each output channel includes thermal shutdown that activates at 85°C to prevent damage. The card also features reverse polarity protection on both inputs and outputs. Additionally, LED indicators display the status of each input and output channel for quick visual diagnostics.

Physical Design and Installation

This digital I/O card features a 50 mm housing that fits standard S5-135U and S5-155U rack slots. The unit weighs approximately 0.45 kilograms, allowing straightforward installation and removal. A 32-pin front connector provides access to all input and output terminals. The card uses screw-type terminals that accept wires from 0.5 mm² to 2.5 mm².

System Integration and Addressing

You can install this I/O card in any slot of the S5-135U or S5-155U central or expansion rack. The card automatically maps its 32 inputs and 32 outputs to consecutive addresses in the I/O table. Users can configure input filters and output default states through the STEP 5 programming software. The card supports both local and remote rack configurations.

Application Guidelines and Environmental Ratings

This I/O card operates reliably from 0°C to 55°C with an IP20 protection rating. For output connections, use appropriate wire gauges to handle the rated current. Always connect the common supply terminals correctly for proper input and output operation. The card meets CE standards for industrial control equipment.