Serial Communication Solution – Siemens 6ES7241-1CH32-0XB0 | CM 1241 RS422/485 | SIMATIC S7-1200
Where This Product Is Used
The Siemens CM 1241 (6ES7241-1CH32-0XB0) is the standard serial communication expansion module for the SIMATIC S7-1200 PLC family. Engineers deploy it wherever a compact controller must exchange data over RS-422 or RS-485 physical layers:
- Modbus RTU master/slave networks – polling field instruments, energy meters, and variable-frequency drives on a shared 2-wire bus in water-treatment plants, HVAC systems, and building automation.
- USS drive communication – controlling Siemens SINAMICS G120 / MICROMASTER 440 drives directly from an S7-1200 without an additional gateway.
- Weighing and barcode systems – reading data from RS-485 scales, label printers, and scanners on packaging and logistics lines.
- Legacy device integration – bridging older RS-422 instruments (flow meters, analyzers) into modern TIA Portal projects.
- Point-to-point ASCII/freeport protocols – custom serial handshakes with third-party PLCs, HMIs, or test equipment.
Technical Specifications
| Order Number (MLFB) | 6ES7241-1CH32-0XB0 |
| Module Name | CM 1241, RS422/485 |
| Compatible CPUs | S7-1200 CPU 1211C / 1212C / 1214C / 1215C / 1217C (all firmware versions) |
| Interface | RS-422 (4-wire, full-duplex) / RS-485 (2-wire, half-duplex) |
| Connector | 9-pin D-Sub (DB9) female |
| Baud Rate | 300 bps – 115.2 kbps |
| Supported Protocols | Modbus RTU, USS, Freeport (ASCII), Point-to-Point |
| Max. Cable Length | 1,000 m (RS-485 at low baud rates) |
| Supply Voltage | 5 V DC (via S7-1200 backplane bus) |
| Current Consumption | ≤ 200 mA from backplane |
| Dimensions (W × H × D) | 30 × 100 × 75 mm |
| Weight | approx. 130 g |
| Operating Temperature | 0 °C … +55 °C (horizontal mounting); 0 °C … +45 °C (vertical) |
| Storage Temperature | −40 °C … +70 °C |
| Protection Class | IP20 |
| Firmware | Configured via TIA Portal V11 SP2 or higher |
Why Engineers Specify This Model
- Native TIA Portal integration – no third-party library required; Modbus RTU and USS instruction blocks are included in the standard firmware package.
- Plug-and-play expansion – snaps onto the left side of any S7-1200 CPU; up to 3 CM modules per CPU without additional power supply.
- Isolated RS-485 bus – galvanic isolation protects the CPU from ground loops common in industrial field wiring.
- Flexible baud rate range – 300 bps to 115.2 kbps covers everything from legacy 9600-baud instruments to high-speed drives.
- Compact form factor – 30 mm wide, ideal for space-constrained control panels.
- Proven field reliability – part of the SIMATIC S7-1200 ecosystem with global installed base exceeding 10 million units.
Complete System Bill of Materials
A typical S7-1200 + CM 1241 Modbus RTU master panel includes:
- Siemens CPU 1214C DC/DC/DC – 6ES7214-1AG40-0XB0
- CM 1241 RS422/485 – 6ES7241-1CH32-0XB0 (this module)
- Siemens SIMATIC HMI KTP700 Basic – 6AV2123-2GB03-0AX0 (optional operator panel)
- 24 V DC Power Supply SITOP PSU100S – 6EP1334-2BA20
- Profibus/RS-485 termination resistor plug – 6ES7972-0DA00-0AA0
- Shielded twisted-pair RS-485 cable (Belden 3105A or equivalent)
Compliance & Industry Standards
- CE marked – EU Machinery Directive 2006/42/EC & EMC Directive 2014/30/EU
- UL listed – UL 508 (Industrial Control Equipment)
- cULus recognized
- ATEX / IECEx – suitable for Zone 2 / Class I Div 2 with appropriate enclosure
- IEC 61131-2 – Programmable Controllers, Equipment Requirements
- RoHS 2011/65/EU compliant
Quality Assurance & Sourcing
Konmask.com sources the 6ES7241-1CH32-0XB0 exclusively through verified Siemens authorized distribution channels. Every unit is:
- Inspected against Siemens factory label, hologram, and date-code standards
- Tested for backplane communication continuity before dispatch
- Shipped in original Siemens ESD-protective packaging
- Accompanied by a certificate of conformity on request
We maintain traceability records for every batch to support your incoming-inspection and audit requirements.
How to Source This Part
Submit your RFQ or place a direct order via Konmask.com. For volume orders (5+ units), OEM projects, or urgent same-day quotations, contact our technical sales team:
- 📧 support@konmask.com
- 📞 +0086 19859288691
- 🌐 https://konmask.com
Lead time: in-stock items ship within 1–3 business days. Ex-stock availability confirmed at time of order.
Application-Specific FAQ
Q: Can the CM 1241 run Modbus RTU master and slave simultaneously?
A: No. The module operates in one role at a time (master or slave), configured in TIA Portal per project requirements.
Q: How many CM 1241 modules can I add to one S7-1200 CPU?
A: Up to 3 communication modules (CM/CB) can be connected to the left side of any S7-1200 CPU.
Q: Is the 6ES7241-1CH32-0XB0 compatible with S7-1500?
A: No. This module is designed exclusively for the S7-1200 platform. For S7-1500, use the CM PtP RS422/485 HF (6ES7541-1AB00-0AB0).
Q: What TIA Portal version is required?
A: TIA Portal V11 SP2 minimum; V16 or higher recommended for full Modbus RTU instruction library support.
Q: Does the module support RS-422 full-duplex at the same time as RS-485?
A: No. The interface mode (RS-422 or RS-485) is selected via wiring and TIA Portal configuration; only one mode is active per installation.
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Contact: support@konmask.com | +0086 19859288691
