Siemens 6ES5524-3UA12 Communication Card

Technical Specifications and Communication Design

This communication card handles serial data exchange for Siemens SIMATIC S5 PLC systems. The Siemens 6ES5524-3UA12 connects the CPU to printers, scales, or barcode readers. You can install this unit into any standard S5-115U, S5-135U, or S5-155U rack slot. Its dual-port architecture processes incoming and outgoing data simultaneously. The card weighs approximately 0.46 kilograms. Its dimensions measure 25 cm in height, 5 cm in width, and 21 cm in depth.

Parameter	Specification
Brand	Siemens
Model	6ES5524-3UA12
Category	Communication Card / Serial Interface Processor
Weight	0.46 kg
Height	25 cm
Width	5 cm (single slot)
Depth	21 cm
Number of Ports	2 independent serial ports
Port 1 Interface	RS-232C (9-pin D-sub)
Port 2 Interface	RS-422 / RS-485 (selectable, 15-pin D-sub)
Communication Speed	300 to 19.2 Kbps (Port 1), 300 to 38.4 Kbps (Port 2)
Protocols Supported	3964R, RK512, ASCII, MODBUS RTU (slave)
Data Buffer Size	2 KB per port (transmit and receive)
Character Format	7 or 8 bits, 1 or 2 stop bits, parity optional
Isolation Voltage	1500V DC (Port 2 only)
Energy Storage	None (no battery)
Component Count	Single PCB with UARTs, buffers, and line drivers

Communication Protocols and Data Handling

The card implements the Siemens 3964R protocol for reliable data exchange. This protocol includes block checks and automatic retries on errors. The Siemens 6ES5524-3UA12 also supports RK512 for point-to-point communication with computers. You can configure ASCII protocol for simple printer or display connections. A separate MODBUS RTU slave mode allows integration with third-party devices. The card buffers incoming data to prevent overrun conditions. Consequently, the CPU can read data at its own pace without loss. Each port includes an 8-position DIP switch for configuration.

Port Features and Signal Capabilities

Port 1 provides standard RS-232 signals for short-distance communication up to 15 meters. This port includes RTS, CTS, DSR, and DTR handshake lines. Port 2 supports RS-422 for distances up to 1200 meters with differential signals. You can also configure Port 2 as RS-485 for multi-drop networks. The Siemens 6ES5524-3UA12 provides +5V and +12V outputs for external converters. A front-panel LED indicates data activity on each port separately. The card automatically detects parity and framing errors in received data.

Installation and Cabling Guidelines

You must insert this card into any standard S5 I/O rack slot. The backplane supplies 5V DC power to the communication circuits. The card draws approximately 220 mA from the 5V supply rail. You must use shielded cables for RS-422 and RS-485 connections. This practice prevents ground loops and electrical noise interference. The Siemens 6ES5524-3UA12 requires no external power supply for operation. You should terminate RS-422 and RS-485 lines at both ends. Termination resistors match the cable impedance and prevent signal reflections.