6ES7241-1CH30-1XB0 CB 1241 RS485 Communication Board S7-1200 | Siemens

The Original New Siemens 6ES7241-1CH30-1XB0 SIMATIC S7-1200 CB 1241 RS485 Communication Board is a compact signal board that plugs directly into the CPU front slot, providing a point‑to‑point RS485 serial interface for the S7‑1200 controller. It supports Freeport, ASCII, Modbus RTU, and USS protocols via terminal block connection, enabling flexible integration with drives, sensors, HMIs, and other serial devices. Powered directly from the CPU backplane, this board preserves the controller’s compact footprint while adding reliable serial communication capability.

Core Engineering Highlights:
RS485 serial interface (2‑wire half‑duplex) | Freeport, ASCII, Modbus RTU master/slave, USS protocols | Terminal block connection | 1 kbyte max telegram length | 50 mA backplane bus current | 1.5 W typical power loss | 38 x 62 x 21 mm | 40 g weight | –20°C to +60°C operating temperature | IP20 protection

Key Features:

• Original New Siemens 6ES7241-1CH30-1XB0 board

• Plugs directly into the S7‑1200 CPU front slot — preserves cabinet space

• RS485 serial interface for point‑to‑point communication

• Terminal block connection for simple wiring

• Supports Freeport, ASCII (library), Modbus RTU (master/slave), and USS (library) protocols

• 1 kbyte maximum telegram length (Freeport, 3964R)

• 7 or 8 data bits, 1 or 2 stop bits, configurable parity

• Address area: 1 to 49,999 (standard Modbus addressing)

• Up to 247 Modbus devices, max. 32 devices per network segment

• Galvanic isolation: 707V DC (type test) between RS485 signal and CPU logic

• 2‑wire half‑duplex RS485, common mode voltage range –7V to +12V

• Integrated 10k pull‑up/pull‑down termination resistors

• Optional 127Ω termination via pin connection

• 1,000 m max shielded cable length

• Baud rates: 300 to 115.2 kbps, 9.6 kbps default

• Diagnostic LEDs: TxD (transmit) and RxD (receive)

• Requires S7‑1200 CPU firmware V2.0 or higher

• Compatible with all SIMATIC S7‑1200 CPUs

Applications:

• Serial communication with Modbus RTU drives, sensors, and instrumentation

• Freeport protocol implementation for custom serial data exchange

• ASCII data transmission to barcode scanners, printers, and displays

• USS protocol communication with Siemens drives (up to 16 drives per RS485 port)

• Integration of legacy RS485 serial devices with S7‑1200 controllers

• Point‑to‑point serial data exchange in factory automation and machine control

Technical Specifications:

• Catalog Number: 6ES7241-1CH30-1XB0

• Product Type Designation: CB 1241 RS485

• Product Family: SIMATIC S7-1200

• Interface Type: RS485 (2‑wire half‑duplex)

• Protocols: Freeport, ASCII, Modbus RTU master/slave, USS

• Data Bits: 7 or 8

• Stop Bits: 1 (default) or 2

• Parity: None (default), even, odd, mark, space

• Baud Rates: 300, 600, 1.2k, 2.4k, 4.8k, 9.6k (default), 19.2k, 38.4k, 57.6k, 76.8k, 115.2k bps

• Max. Telegram Length: 1 kbyte

• Modbus Address Range: 1 to 49,999

• Max. Modbus Devices: 247; 32 per network segment without repeaters

• Cable Length (Shielded, Max): 1,000 m

• Galvanic Isolation: 707V DC (type test), RS485 signal to CPU logic

• Common Mode Voltage Range: –7V to +12V

• Differential Output Voltage: 2V min (100Ω load), 1.5V min (54Ω load)

• Receiver Input Impedance: 5.4 kΩ min, including termination

• Receiver Threshold: ±0.2V min, 60 mV hysteresis typical

• Termination: 10k pull‑up/pull‑down; optional 127Ω termination

• Backplane Bus Current (5V DC, Typ.): 50 mA

• Power Loss (Typ.): 1.5 W

• Diagnostics: TxD and RxD LEDs

• Dimensions (W x H x D): 38 x 62 x 21 mm

• Weight: Approx. 40 g

• Enclosure Type: IP20

• Mounting: Plugs directly into CPU front slot

• Operating Temperature: –20°C to +60°C

• Storage Temperature: Refer to product manual

• CPU Firmware Requirement: V2.0 or higher

• Engineering: TIA Portal V11 or higher

• Certifications: CE, cULus, RoHS

System Compatibility:

• Siemens SIMATIC S7‑1200 CPUs (all variants)

• TIA Portal engineering framework (V11 or higher)

• S7‑1200 CPU firmware V2.0 or higher

• Up to one CB 1241 board and three CM 1241 modules per S7‑1200 CPU

• Modbus RTU master/slave devices

• USS protocol drives

• Freeport and ASCII serial devices

Typical System Architecture:
S7‑1200 CPU
│
├── 6ES7241-1CH30-1XB0 CB 1241 RS485 Board (plugs directly into CPU front slot)
│ ├── RS485 Terminal Block → Serial Devices (Drives, Sensors, HMIs, Barcode Scanners)
│ ├── Modbus RTU Master/Slave → Up to 247 Devices (32 per segment)
│ ├── Freeport / ASCII / USS Protocols → Flexible Serial Communication
│ └── TxD/RxD LEDs → Communication Status Monitoring
│
↓
TIA Portal Engineering (V11 or higher)
↓
Point‑to‑Point Serial Communication Application

Related Products:

• 6ES7241-1CH30-1XB0 – CB 1241 RS485 (current model)

• 6ES7241-1CH32-0XB0 – CM 1241 RS422/485 communication module (higher channel count)

• 6ES7241-1AH32-0XB0 – CM 1241 RS232 communication module

• 6ES7214-1AG40-0XB0 – CPU 1214C DC/DC/DC (recommended CPU)

• 6ES7274-1XF30-0XA0 – SIMATIC Memory Card for S7‑1200

PLC ERA is an independent industrial automation distributor supplying 100% genuine Original New products through established global supply channels. Siemens, SIMATIC, S7‑1200, and TIA Portal are trademarks of Siemens AG.