6ES7241-1CH32-0XB0 SIMATIC S7-1200 Communication Module CM 1241 (RS422 / RS485).

The 6ES7241-1CH32-0XB0 is the Siemens article number for a SIMATIC S7-1200 Communication Module CM 1241 (RS422 / RS485).

Unlike the CPU units you looked at earlier, this is an expansion module that mounts onto the left side of an S7-1200 CPU to add serial point-to-point (PtP) communication capabilities.

The core technical specifications for this module are broken down below:

General Information & Setup

• Module Designation: CM 1241 RS 422 / 485

• Placement: Attaches to the left-hand expansion interface of any S7-1200 CPU. Up to 3 communication modules can be added to a single controller setup.

Electrical & Power Data

• Supply Voltage: 24 V DC (Permissible range: 20.4 V to 28.8 V DC).

• Current Consumption: Max 220 mA from the backplane bus (5 V DC).

• Power Loss: Typically around 1.1 W.

• Electrical Isolation: Integrated potential separation between the serial interface and the CPU logic circuits.

Physical Interface

• Connection Port: 1 x 9-pin D-sub (Sub-D) female socket.

• Physical Standard: Supports both RS422 (X.27) 4-wire balanced configurations and RS485 2-wire multi-drop networks.

• Maximum Cable Length: Up to 1,000 meters (depending on transmission speed and cable quality).

Supported Protocols & Drivers

The module is highly flexible for connecting to third-party hardware (like drives, bar code readers, old modems, or alternative PLCs) via native protocol drivers:

• Modbus RTU: Full native support for functioning as a Modbus RTU Master or Modbus RTU Device/Slave (supports address area 1 to 49,999; max 247 slave devices per network with appropriate repeaters).

• Freeport / ASCII: Supports message-based, raw serial communication for building custom character-string string telegrams (up to 1 Kbyte telegram lengths).

• 3964 (R): High-reliability Siemens serial handshake protocol.

• USS Protocol: Supported via a downloadable instruction library for controlling older serial-driven motor drives.

Configuration Parameters

• Data Bits: 7 or 8 bits per character.

• Stop Bits: 1 or 2.

• Parity Options: None, Even, Odd, Mark, or Space.

Physical Dimensions

• Dimensions (W x H x D): 30 mm x 100 mm x 75 mm (takes up 1 standard module width slot on the rail).

• Net Weight: ~155 grams.

• Protection Rating: IP20.