Siemens 6ES5525-3UA11 Communications Processor

This communications processor handles data exchange between SIMATIC S5 and external devices. It manages RS-232 serial communication for printers, scanners, or host computers. You can configure this module for point-to-point or multipoint networks.

Technical Specifications

Parameter	Details
Brand	Siemens
Model	Siemens 6ES5525-3UA11
Category	Communications Processor (SIMATIC S5 Series)
Dimensions (H x W x D)	250 mm x 25 mm x 210 mm
Weight	0.58 kg
Communication Protocol	ASCII, RK512, or 3964R
Physical Interface	1x RS-232 (9-pin D-sub)
Data Rate Range	300 bit/s to 19.2 kbit/s
Transmission Mode	Half-duplex or full-duplex
Internal Buffer	2 KB FIFO for receive and transmit
Number of Internal Components	1 CPU + 2 UARTs + 1 buffer RAM + 1 PCB
Maximum Cable Length	15 meters (RS-232, shielded)
Parity Options	None, even, odd, or mark/space
Data Bits	7 or 8 bits
Stop Bits	1 or 2 bits
Power Supply	5 V DC from backplane only
Current Draw (5V)	250 mA typical
Built-in Energy Storage	100 µF capacitor for buffer retention
Status Indicators	4 LEDs (TX, RX, ERR, READY)
Operating Temperature	0°C to 60°C

Detailed Feature Overview

This communications processor supports ASCII, RK512, and 3964R protocols. You can select the appropriate protocol via STEP 5 configuration software. The module includes a 2 KB FIFO buffer for smooth data flow.

A 100 µF capacitor retains the buffer during brief power interruptions. Consequently, you avoid losing partially received messages during brownouts. The RS-232 port operates at speeds from 300 baud up to 19.2 kbaud.

You will find four status LEDs on the front panel. These LEDs show transmit activity, receive activity, errors, and module readiness. The maximum RS-232 cable length reaches 15 meters with proper shielding.

Installation and Programming

Siemens 6ES5525-3UA11 fits any S5 rack slot except the CPU position. Use STEP 5 software to configure the serial parameters. Connect the serial cable only after removing backplane power.