Siemens 6ES7137-6AA01-0BA0 — ET 200SP Serial Module Selection Guide

By Abdullah Zahid
12 min read
Siemens 6ES7137-6AA01-0BA0 CM PtP serial communication module for ET 200SP RS-232 RS-485 integration

Siemens 6ES7137-6AA01-0BA0 CM PtP Communication Module for Serial Connection RS-422, RS-485 and RS-232 — Specifications, Price, and Selection Guide

Controls engineers integrating legacy serial devices into modern SIMATIC distributed I/O architectures frequently arrive at the same crossroads: which ET 200SP communication module handles the actual protocol on their device? The Siemens 6ES7137-6AA01-0BA0 is the SIMATIC ET 200SP CM PtP Communication Module for serial connection RS-422, RS-485 and RS-232 — a 15mm-wide, DIN-rail-mounted module that adds RS-232, RS-422, and RS-485 serial port capability to ET 200SP distributed I/O stations, supporting Modbus RTU, USS, Freeport, and 3964(R) protocols from a single catalog number. It draws 31mA at 24V DC nominal and operates between -30 and 60°C in horizontal mounting, making it a dependable choice for retrofitting brownfield serial equipment into S7-1200, S7-1500, S7-300, and S7-400 systems without displacing the existing hardware chain.

If you have already confirmed this is the right part, check current pricing and availability at LeadTime.ca — ships worldwide.

Who Should Buy the 6ES7137-6AA01-0BA0 — and Who Shouldn't

This module is the correct choice when your application requires point-to-point serial communication within an ET 200SP distributed I/O rack. Buy this part if all of the following apply to your project:

  • Your legacy device communicates over RS-232, RS-422, or RS-485 using Modbus RTU, USS, Freeport, or 3964(R) protocol
  • Your controller is a SIMATIC S7-300, S7-400, S7-1200, or S7-1500 — or a standard PROFINET controller
  • Your ET 200SP base unit is type A0 with an available module slot
  • Your 24V DC power supply delivers between 19.2V and 28.8V with at least 35mA of current headroom for this module
  • Your panel space is constrained — 15mm module width allows dense rack packing in tight enclosures
  • Your installation environment stays within -30 to 60°C (horizontal) and below 5,000 meters altitude

If your network uses CANopen, you need the 6ES7137-6EA00-0BA0 (CM CAN) instead. If you are connecting IO-Link sensors or actuators, the 6ES7137-6BD00-0BA0 (CM IO-Link) is the correct module. If your environment operates beyond -30 to 60°C or requires hazardous-location certification beyond what the standard variant provides, order the SIPLUS extreme variant before committing to this one.

On this page:

What the 6ES7137-6AA01-0BA0 Actually Does in a Running System

The CM PtP designation stands for Communication Module Point-to-Point — a direct description of the module's role. Rather than participating in a bus or network topology, this module creates a dedicated serial gateway between the ET 200SP backplane and a single external serial device. It does not require a separate communication card in the main PLC chassis; it sits in the ET 200SP I/O rack, communicates to the controller via the internal backplane, and presents a serial port to the outside world through its terminal connections.

In practical terms, this means a SINAMICS drive communicating over USS protocol, a legacy energy meter on Modbus RTU, a proprietary barcode reader using Freeport passthrough, or an older Siemens device on 3964(R) can all be connected to a modern S7-1500 system through this single module — without replacing the field device, changing the PLC platform, or adding a separate gateway appliance. The module's 4 kbyte buffer and capacity to hold 255 telegrams provides enough headroom to handle short communication bursts without dropping data when the controller is occupied with other tasks.

The backplane-to-serial interface isolation is tested at 707V DC, which matters when connecting to equipment on a different electrical ground potential. Built-in reverse polarity protection on the 24V supply and wire-break detection on serial lines reduce commissioning risk and simplify fault diagnosis in the field. All four status LEDs — PWR, DIAG, RxD, and TxD — give a technician standing at the panel immediate visual confirmation of power status, module health, and live serial data flow in both directions.

Typical System Architecture: Where This Module Sits

The 6ES7137-6AA01-0BA0 sits between the ET 200SP distributed I/O rack and a serial field device, acting as the protocol translator and data buffer on the backplane segment of your distributed architecture. Here is a typical component chain:

  • SIMATIC S7-1500 or S7-1200 PLC (or S7-300/400 with ET 200SP adapter) connected via PROFINET to the ET 200SP station
  • ET 200SP IM (interface module) receives PROFINET and distributes backplane communication to all modules in the rack
  • ET 200SP base unit type A0 hosts the 6ES7137-6AA01-0BA0 in its assigned slot — the backplane connector carries data and 24V DC power
  • The CM PtP module's serial terminals connect directly to the RS-232, RS-422, or RS-485 port of the legacy field device (VFD, energy meter, barcode reader, servo drive, etc.)
  • TIA Portal manages module configuration, protocol selection, address space assignment, and firmware updates without additional software licenses

Industries and Applications Where This Module Gets Specified

The most common scenario is brownfield modernization: a plant replaces its S7-300 or S7-400 PLC with a newer S7-1500 platform but retains the field devices because replacing variable frequency drives, scales, or serial sensors on the floor would exceed project budget. The 6ES7137-6AA01-0BA0 absorbs the serial protocol burden at the distributed I/O level, allowing the new controller to communicate with legacy hardware without modification to either end.

In automotive and discrete parts manufacturing, USS protocol communication with SINAMICS servo drives is a frequent integration requirement during retrofit projects. A single 6ES7137-6AA01-0BA0 per drive can be installed in an ET 200SP rack close to the machine, keeping cable runs short and serial signal integrity high — RS-485 and RS-422 operate reliably up to 1,200 meters, which covers multi-building industrial facilities without repeaters.

Food and beverage processing facilities frequently integrate proprietary checkweighers, filling machines, and labeling equipment with custom serial protocols. Freeport mode on this module provides a transparent passthrough that allows the PLC program to handle the protocol framing directly, eliminating the need for a third-party protocol converter appliance and its associated failure point.

Pharmaceutical and water/wastewater applications benefit from the module's diagnostic capabilities — wire-break detection, DIAG LED fault indication, and I&M0 to I&M3 identification data support auditable asset management and simplify maintenance documentation requirements.

Application Typical Deployment
VFD integration via Modbus RTU ET 200SP rack near motor control center, S7-1500 over PROFINET
SINAMICS servo drive communication (USS) One module per drive axis, distributed rack at machine base
Legacy barcode reader or scale via Freeport ET 200SP station on conveyor line, custom protocol handled in PLC program
Energy meter integration (Modbus RTU) Panel-mounted ET 200SP rack, S7-1200 as PROFINET controller
Brownfield S7-300 serial device migration Retrofit ET 200SP station replacing legacy serial card, S7-1500 CPU
Proprietary vendor equipment (3964/R) ET 200SP station adjacent to vendor panel, backplane to PROFINET

Purchase-Decision Specifications at a Glance

Parameter Value
Supply Voltage (nominal) 24V DC
Supply Voltage (permissible range) 19.2 to 28.8V DC
Current Consumption (maximum) 35mA
Power Loss (typical) 0.7W
Serial Interfaces Supported RS-232, RS-422, RS-485
Max Transmission Rate (RS-422/RS-485) 115.2 kbit/s
Max Cable Length 1,200 m (speed dependent)
Protocols Supported Modbus RTU (master/slave), USS, Freeport, 3964(R)
Operating Temperature (horizontal) -30 to 60°C
Dimensions (W x H x D) 15mm x 73mm x 58mm / 30g

Full technical specifications are available on the product page at LeadTime.ca.

6ES7137-6AA01-0BA0 vs. 6ES7137-6EA00-0BA0 vs. 6ES7137-6BD00-0BA0: Which One Do You Actually Need?

Model Number Protocol Best For Key Difference
6ES7137-6AA01-0BA0 RS-232 / RS-422 / RS-485 (Modbus RTU, USS, Freeport, 3964/R) Serial device integration, legacy equipment retrofit Point-to-point serial — all three RS standards on one module
6ES7137-6EA00-0BA0 CANopen Modern CAN networks, CANopen device integration Protocol only — no RS serial interfaces
6ES7137-6BD00-0BA0 IO-Link Smart sensors and actuators with IO-Link interface Protocol only — no RS serial or CAN interfaces
SIPLUS extreme variants Same as 6ES7137-6AA01-0BA0 Harsh environments, extended temperature, hazard zones Extended temperature and hazardous-location certification

If your architecture uses RS-232, RS-422, or RS-485 serial devices with Modbus RTU, USS, Freeport, or 3964(R), the 6ES7137-6AA01-0BA0 is the correct choice — check current availability at LeadTime.ca.

Expert Verdict: Honest Assessment for Engineers and Procurement Teams

The 6ES7137-6AA01-0BA0 earns its place in SIMATIC distributed I/O architectures by solving a specific and persistent problem: keeping legacy serial devices alive in modern control systems without external converters or protocol gateways. Its 15mm width is genuinely useful in crowded ET 200SP racks. The combination of Modbus RTU master and slave modes, USS for SINAMICS drives, Freeport for custom protocols, and 3964(R) for legacy Siemens devices in a single part number reduces the SKU count a panel builder or integrator needs to stock. The 4 kbyte buffer and 255-telegram capacity are sufficient for all standard serial communication cycles at speeds up to 115.2 kbit/s on RS-422 and RS-485.

The honest limitations: this module does not support isochronous mode, so it is not suitable for applications requiring real-time synchronized I/O across a deterministic cycle. It has no integrated hardware interrupt capability, meaning time-critical serial events must be polled or managed through PLC program logic. If your legacy device uses CANopen, this module will not work — the 6ES7137-6EA00-0BA0 is the only correct answer in that case. And if your installation site pushes beyond -30 to 60°C in horizontal mounting, or if your hazardous-area classification requires FM, CCC-Ex, or KC certification at a standard-model level, verify the SIPLUS extreme variant before ordering the base model. Lead times from ex-works are approximately 130 days as a standard product, which is the primary procurement risk for project-driven buyers — early ordering is the only mitigation.

For procurement teams: this is a classification A standard product, returnable within the standard returns period, with firmware updates included at no charge. WEEE take-back obligations apply at end of life. Pricing in the market sits in approximately the $200–$250 USD range depending on supplier and region, but module cost is typically a small fraction of total ET 200SP rack implementation when base units, power supplies, and installation labor are included. If this matches your system requirements, view current stock and pricing at LeadTime.ca.

For volume pricing or to confirm lead time before committing to a build, contact the LeadTime.ca team directly — we ship worldwide.

Wiring and Installation Overview

  • The module uses a push-in terminal connection design and seats into an ET 200SP type A0 base unit using a type D mechanical coding element — confirm base unit type and coding alignment before installation
  • Connect 24V DC supply within the 19.2 to 28.8V permissible range; built-in reverse polarity protection is present, but the module will not function with reversed polarity until corrected — verify with a multimeter before applying power
  • RS-485 and RS-422 multipoint configurations require 120-ohm terminating resistors at the two physical ends of the cable run; all RS-422 4-wire full duplex and multipoint wiring must match the pin assignments in the manufacturer datasheet
  • Maximum cable length for RS-232, RS-422, and RS-485 is 1,200 meters depending on transmission speed — longer runs at higher baud rates reduce signal integrity; consult the datasheet cable length vs. baud rate table for your specific configuration
  • After physical installation, verify the PWR LED illuminates green and the DIAG LED shows no red indication before applying communication configuration in TIA Portal

Compatible ET 200SP Base Units and Controller Integration

The 6ES7137-6AA01-0BA0 is confirmed compatible with ET 200SP base unit type A0 and integrates with the following SIMATIC controllers via the ET 200SP distributed I/O backplane and PROFINET:

  • SIMATIC S7-1500 — native ET 200SP integration via PROFINET, full TIA Portal configuration
  • SIMATIC S7-1200 — requires firmware version confirmed in TIA Portal; full protocol support available
  • SIMATIC S7-300 — compatible with ET 200SP adapter configuration
  • SIMATIC S7-400 — compatible with ET 200SP adapter configuration
  • Standard PROFINET controllers — module communicates via ET 200SP backplane to any PROFINET-capable controller
  • TIA Portal configuration supports I&M0 to I&M3 identification and maintenance data, address space selection (8-byte standard or 32-byte performance mode), and firmware updates

What Engineers Get Wrong When Ordering This Module

Before placing your order, run through every item on this checklist. Each point corresponds to a real procurement or installation mistake that leads to incorrect parts, project delays, or failed commissioning:

  1. Confirm ET 200SP base unit type is compatible (BU type A0 confirmed for this module)
  2. Verify controller is SIMATIC S7-300/400/1200/1500 or standard PROFINET controller
  3. Check if point-to-point serial communication is the actual requirement (not CAN or IO-Link)
  4. Confirm 24V DC power supply exists with 19.2-28.8V capacity
  5. Verify protocol support needed (Modbus RTU, USS, Freeport, or 3964/R) is available in device
  6. Check that RS interface type (232/422/485) matches legacy equipment being integrated
  7. Ensure application does not require isochronous mode (this module does not support it)
  8. Review if extreme temperature/hazardous location variant is required before ordering standard version

If any item on this list is unresolved, contact the LeadTime.ca team before ordering — the 130-day ex-works lead time makes a wrong-part return costly in both time and project scheduling.

Frequently Asked Questions

Can the 6ES7137-6AA01-0BA0 act as both a Modbus RTU master and a Modbus RTU slave?

Yes. The module supports Modbus RTU in both master and slave modes, as well as Freeport and 3964(R) in both master and slave configurations. USS protocol support is included for SINAMICS drive communication. Protocol selection is made in TIA Portal during configuration, not by hardware switch.

What is the realistic lead time for the 6ES7137-6AA01-0BA0 and how should I plan around it?

Standard ex-works lead time is approximately 130 days for this German-manufactured module. This is the most common procurement risk for project-driven buyers. Early ordering — ideally at the project design stage rather than the installation stage — is the only reliable mitigation. LeadTime.ca can confirm current stock status and lead time before you commit. Contact the team for an up-to-date availability check.

Does this module work with S7-1200 controllers, and are there firmware requirements?

The 6ES7137-6AA01-0BA0 is compatible with SIMATIC S7-1200 controllers. Firmware version requirements must be confirmed in TIA Portal against the module's firmware — consult the Siemens product documentation or your TIA Portal project for the specific minimum version required for your S7-1200 CPU revision.

What is the maximum cable length for RS-485 communication with this module?

RS-485 and RS-422 interfaces support cable lengths up to 1,200 meters, with the actual maximum dependent on the transmission speed selected. At higher baud rates, the practical cable length decreases. At the maximum rated speed of 115.2 kbit/s, consult the Siemens datasheet cable length vs. baud rate table for your specific run distance before finalizing your wiring design.

Is the standard 6ES7137-6AA01-0BA0 suitable for use in hazardous or explosive atmosphere locations?

The standard variant carries KC, CCC-Ex, and FM certifications, but if your application requires operation in extreme temperature ranges below -30°C or above 60°C, or in hazardous-location environments beyond the standard variant's certifications, the SIPLUS extreme variant is required. Do not install the standard model in environments that exceed its rated conditions without first verifying certification applicability against your local safety authority requirements.

Can I configure address space in performance mode, and what does that change?

Yes. The module supports standard mode with 8 bytes of input address space and 0 bytes of output address space, or performance mode with 32 bytes each for input and output. Performance mode increases the data throughput available to the PLC program and is recommended for high-volume serial communication applications. Address space configuration is set in TIA Portal module properties and does not require hardware changes.

Why Order From LeadTime.ca

  • LeadTime.ca ships the 6ES7137-6AA01-0BA0 worldwide — no geographic restriction on sourcing
  • Current stock levels and confirmed lead times are available on request before you commit — critical for the 130-day ex-works timeline on this module
  • Volume pricing available for multi-unit project builds and panel shop procurement — contact the team directly for project pricing
  • Hard-to-source automation components including SIMATIC ET 200SP modules are a core part of the catalog, not a secondary offering
  • Technical familiarity with SIMATIC product families means faster quote turnaround and fewer back-and-forth compatibility questions

At-a-Glance Summary

  • Model: 6ES7137-6AA01-0BA0 — SIMATIC ET 200SP CM PtP Communication Module for RS-232, RS-422, RS-485
  • Supply voltage: 24V DC nominal, permissible range 19.2 to 28.8V DC
  • Current draw: 31mA rated, 35mA maximum; power loss 0.7W typical
  • Serial interfaces: RS-232, RS-422 (115.2 kbit/s max), RS-485 (115.2 kbit/s max)
  • Maximum cable length: 1,200 meters on RS-422 and RS-485 (speed dependent)
  • Protocols: Modbus RTU (master and slave), USS, Freeport (master and slave), 3964(R) (master and slave)
  • Buffer: 4 kbyte capacity, 255 telegrams bufferable
  • Address space: 8-byte standard mode, 32-byte performance mode
  • Operating temperature: -30 to 60°C horizontal, -30 to 50°C vertical
  • Dimensions: 15mm x 73mm x 58mm; weight 30g
  • Compatible controllers: S7-300, S7-400, S7-1200, S7-1500, PROFINET controllers
  • Base unit compatibility: ET 200SP type A0
  • Certifications: KC, CCC-Ex, FM; RoHS compliant since April 30, 2021; WEEE obligation applies
  • Standard ex-works lead time: approximately 130 days — plan procurement early
  • Isochronous mode: not supported — verify this constraint against your application before ordering