Siemens 6ES5304-3UA12 Interface Module

The Siemens 6ES5304-3UA12 Interface Module connects SIMATIC S5 systems to SINEC L1 networks. This module handles communication between multiple PLCs on a single bus. You will find it in distributed control systems across factory floors. It supports up to 32 stations on a single network segment. Therefore, this unit enables peer-to-peer data exchange without additional cabling.

The Siemens 6ES5304-3UA12 Interface Module measures 230 mm in height and 48 mm in width. Its depth reaches 180 mm for standard rack mounting. The unit weighs approximately 0.59 kilograms. It contains one 16-bit processor and two network ports. Four status LEDs provide network and diagnostic information. Additionally, you get a 9-pin D-sub connector for bus connection.

Key Technical Specifications

Parameter	Value
Manufacturer	Siemens AG
Model	6ES5304-3UA12
Product Type	Interface Module
Network Protocol	SINEC L1 (187.5 kbps)
Network Ports	2 (9-pin D-sub, female)
Maximum Stations	32 per segment
Cable Length	500 meters (maximum)
Processor	16-bit @ 16 MHz
Memory	64 KB (program + data)
Height	230 mm
Width	48 mm
Depth	180 mm
Weight	0.59 kg
Status LEDs	4 (PWR, RUN, TX, RX)
Energy Storage	≈ 220 µF (capacitive)
Power Consumption	280 mA @ 5 VDC
Isolation Rating	1500 VAC (optical)
Operating Temperature	0°C to +60°C
Mounting Method	S5 rack
Configuration	Software only

Internal Architecture and Energy Storage

The Siemens 6ES5304-3UA12 Interface Module stores minimal energy in its power filter. Small electrolytic capacitors hold approximately 220 microfarads total capacitance. A 16-bit processor runs the SINEC L1 protocol stack independently. This processor handles all token-passing and message routing functions. Two network ports allow daisy-chaining of multiple stations on one segment. Four optical isolators protect the backplane from network transients. The module includes 64 KB of memory for buffer and configuration storage. Four LEDs show power, run, transmit, and receive status clearly. A green RUN LED lights up when the module communicates with the CPU normally.

Connection Interfaces and Wiring Details

You will find two 9-pin D-sub female connectors on the front panel. Connect the SINEC L1 cable to Port 1 for network access. Use Port 2 to daisy-chain to the next station on the bus. The Siemens 6ES5304-3UA12 Interface Module requires proper termination at both network ends. Connect the A wire to pin 3 and the B wire to pin 8. Connect the shield drain wire to pin 1 (ground). Use shielded twisted-pair cable for all network connections. Four LEDs indicate power, run, transmit, and receive status. A green TX LED flashes during message transmission from this station. A green RX LED flashes during message reception from other stations.

Configuration and Installation Steps

You slide this module into any I/O slot of the SIMATIC S5 rack. First, align the module with the upper and lower card guides. Then, push it firmly until the backplane connector seats completely. Secure the front panel with the two retaining screws. Connect the SINEC L1 cable to the network ports. The Siemens 6ES5304-3UA12 Interface Module consumes 280 mA from the backplane supply. Use the STEP 5 software to configure network parameters. Assign a unique station address from 1 to 32 using the software. Set the communication parameters including baud rate and timeout values. Download the configuration to the module’s internal memory. Test communication with all network stations before system startup.