Siemens 6AG2155-6AU01-4BN0 — SIPLUS ET 200SP PROFINET Interface Module

1. Product Overview

The 6AG2155-6AU01-4BN0 is a SIPLUS ET 200SP IM 155-6 PN ST TX RAIL interface module designed to connect a distributed I/O station to a PROFINET industrial communication network. It is used in automation systems where sensors, actuators, and other field devices are connected to remote I/O modules rather than being wired individually to the central PLC cabinet.

The module is based on the standard 6ES7155-6AU01-0BN0 and belongs to the SIPLUS extreme RAIL interface-module family. It features conformal coating for demanding environmental conditions and a specified operating temperature range of -40°C to +70°C, with a short-duration temperature condition of +85°C for up to 10 minutes under applicable railway operating conditions.

The module provides a PROFINET interface with one BusAdapter slot. It supports up to 32 ET 200SP I/O modules and up to 16 ET 200AL modules in supported configurations. It also supports single-module hot swapping, subject to the system configuration and prescribed maintenance procedure.

Unlike a PLC CPU, this product does not execute the main automation program. Its role is to manage communication between the controller and the distributed I/O station, allowing the controller to read input values and update output data over the network.

The product is suited to railway-related equipment and industrial installations where temperature variation, environmental exposure, compact installation, and reliable remote I/O communication are important considerations.

2. Basic Product Information

The distinction between the module’s weight and the order configuration’s net weight matters when planning cabinet loads, spare-parts inventory, or shipping. The dimensions above refer to the interface module’s physical envelope, not the external dimensions of a shipping package.

3. Detailed Technical Parameters

The following table provides a more detailed reference for electrical supply, communication, station capacity, environmental conditions, and mechanical installation.

Electrical consumption and station limits are configuration-dependent values. The exact module revision, connected I/O modules, network setup, and engineering software should be checked before finalizing a design.

4. Product Introduction

4.1 Role in a distributed automation system

In a conventional centralized automation layout, a large number of field cables may need to run from sensors and actuators back to the main control cabinet. This can increase cable length, installation effort, and the complexity of maintenance.

A distributed I/O architecture places remote I/O stations closer to the equipment they serve. The station collects local field signals and communicates with the central controller through an industrial network.

The 6AG2155-6AU01-4BN0 provides the PROFINET interface for a compatible ET 200SP station. It manages communication between the controller and the installed peripheral modules, allowing the PLC program to read input states and update output values.

For example, a production line may have one remote I/O station for a conveyor section and another for a packaging machine. Each station gathers signals from its local sensors and actuators, while the central controller coordinates the overall production sequence.

4.2 Standard-function interface

The IM 155-6 PN ST designation identifies the module as a standard-function PROFINET interface. It supports distributed I/O communication and single-module hot swapping, but it should not be confused with the high-functionality HF variants.

This distinction matters during system design. Applications requiring features such as S2 system redundancy, multi-module hot swapping, or isochronous operation should be checked against a compatible HF model rather than assuming those functions are available in this ST variant.

4.3 SIPLUS RAIL design

The SIPLUS RAIL version is designed for applications with more demanding environmental conditions than those typically encountered in a clean, temperature-controlled indoor installation.

Its conformal coating provides additional protection to electronic assemblies against specified environmental influences. The stated operating range of -40°C to +70°C supports use in systems that experience low temperatures or significant temperature variation.

The specified +85°C condition applies for a limited duration of 10 minutes under the applicable railway operating conditions. It should not be interpreted as a continuous operating temperature.

The module remains an IP20 device and must be installed in an enclosure appropriate for the actual environment.

5. Product Applications

5.1 Railway automation

Railway installations can expose electronic equipment to temperature variation, vibration, mechanical shock, and environmental contamination. The SIPLUS RAIL version is intended for applications that require the relevant environmental protection characteristics.

It can be used as the communication interface for a distributed I/O station in suitable railway equipment and infrastructure systems.

Potential applications include auxiliary equipment monitoring, service-system control, ventilation equipment, and railway infrastructure automation. The suitability of the complete system depends on the installation, qualification documentation, and applicable railway requirements.

5.2 Industrial machine control

Large machines often have field devices spread across different sections. A remote I/O station allows these signals to be collected near the equipment rather than routed individually to a central cabinet.

The interface module connects the station to the PROFINET controller, which can then coordinate the machine’s sensors, actuators, and operating sequences.

Typical applications include packaging machinery, conveyor systems, material handling, assembly equipment, and automated production lines.

5.3 Distributed process control

Industrial processes often include pumps, valves, motors, sensors, and auxiliary equipment distributed around a facility.

An ET 200SP station can collect local signals from compatible input modules and deliver output commands through compatible output modules. The interface module manages the communication with the controller.

Possible applications include water treatment, utility systems, fluid handling, industrial ventilation, and selected process-control installations.

5.4 Infrastructure and remote equipment cabinets

Some automation equipment is installed in remote cabinets, service areas, tunnels, or locations with limited climate control.

A distributed I/O station can reduce the need to route all field signals back to a single central location. The SIPLUS interface module may be considered when its environmental specifications match the installation conditions.

Enclosure design, grounding, power supply quality, cable routing, and environmental protection remain essential to reliable operation.

5.5 Equipment status monitoring

A distributed station can gather discrete status signals from switches, contacts, and compatible sensors. Analog modules can be added where continuous process measurements are required.

The interface module transfers the station’s process data to the controller, where the program can record conditions, generate alarms, and initiate maintenance or operating procedures.

The interface module does not directly measure temperature, pressure, flow, or other process variables. Those functions are provided by the appropriate field instruments and I/O modules.

5.6 Modular production systems

The ET 200SP platform supports a range of compatible peripheral modules, allowing the station to be tailored to the machine’s I/O requirements.

This can simplify the organization of distributed signals and make later changes easier when additional sensors or actuators are introduced.

The actual station size and module combination must remain within the interface’s supported configuration and electrical limits.

6. Product Advantages

6.1 Extended operating temperature range

The specified operating range of -40°C to +70°C is one of the key features of this SIPLUS RAIL model.

It can be useful in industrial installations exposed to low ambient temperatures, outdoor-related temperature variation, or equipment locations where temperature control is limited.

The short-duration +85°C condition provides additional flexibility under specified railway operating conditions, but it does not replace the continuous operating-temperature limit.

6.2 Conformal coating

The conformal coating provides additional protection for the electronic assemblies against specified environmental influences.

This can help improve the module’s suitability for railway and industrial applications where environmental exposure is a concern.

It does not make the module waterproof or suitable for unrestricted exposure to dust, condensation, or chemicals. A suitable enclosure and proper installation remain necessary.

6.3 Efficient distributed I/O communication

The module connects the ET 200SP station to a PROFINET network, allowing local field signals to be exchanged with the central controller.

This can reduce extensive point-to-point field wiring and make the system easier to organize by machine section or process area.

It also gives engineers flexibility when deciding where to locate the I/O station in relation to the equipment it serves.

6.4 Support for a modular station

The module supports up to 32 ET 200SP modules and up to 16 ET 200AL modules in supported configurations.

This provides flexibility when the station needs a mixture of digital and analog signal types. The actual functions depend on the peripheral modules installed.

6.5 Single-module hot swapping

The supported single-module hot-swapping function can simplify certain maintenance procedures by allowing an eligible module to be replaced while the station remains in operation.

This may reduce downtime in appropriately designed systems.

Hot swapping is not unrestricted. The station configuration, module type, and operating conditions must support the procedure, and the approved maintenance instructions must be followed.

6.6 Compact dimensions

The interface module measures 50 × 117 × 74 mm, making it suitable for many compact control-cabinet layouts.

The approximate weight is 0.147 kg without a BusAdapter, while the listed net weight for the relevant order configuration is approximately 0.170 kg.

These values are useful for preliminary planning. The complete installation should also allow space for the BusAdapter, network cabling, adjacent modules, ventilation, and maintenance access.

6.7 Clear distinction between standard and high-functionality variants

The ST interface is suitable for many general distributed I/O applications that need PROFINET communication and single-module hot swapping.

This helps engineers select a module according to actual requirements rather than paying for advanced functionality that the application does not use.

If the project requires S2 redundancy, multi-module hot swapping, or isochronous operation, the relevant HF interface should be evaluated instead.

7. Five Related Models

The following models belong to the same distributed I/O family or provide closely related interface functionality. They can be considered when planning a new station, expanding an existing system, or replacing an interface module.

The weights above refer to different supplied configurations, so they should not be compared as though every row represents the same package contents. In particular, bundle products may include a server module and BusAdapter, while standalone interface-module products may not.

7.1 How to choose among the related models

6AG2155-6AU01-4BN0 — Standard-function RAIL interface

This is the model to consider when the system requires a standard-function PROFINET interface with single-module hot swapping and the specified SIPLUS RAIL environmental protection.

6AG2155-6AU02-4BN0 — Multi-module hot-swapping variant

This variant is worth evaluating when the maintenance strategy requires support for multi-module hot swapping. Check the station configuration and replacement procedure before choosing it.

6AG2155-6AA01-4BN0 — Bundle with two-port RJ45 BusAdapter

This option can simplify procurement when the required interface module, server module, and two-port RJ45 BusAdapter are needed together.

6AG2155-6AA02-4BN0 — Bundle with multi-module hot swapping

This bundle may be suitable when the application requires the corresponding ST interface, BusAdapter, and multi-module hot-swapping functionality.

6AG2155-6AU01-4CN0 — High-functionality interface

Consider this model when advanced features such as S2 redundancy, multi-module hot swapping, or isochronous operation are required. It is not a direct, feature-for-feature replacement for the ST variant.

Before making a substitution, compare the full order number, BusAdapter arrangement, firmware compatibility, supported module count, environmental rating, and hot-swapping requirements.

8. Five Popular Models from the Same Brand

The following products cover common PLC and distributed I/O functions that may be used alongside the 6AG2155-6AU01-4BN0 in a wider automation system.

The first three models are closely related to the target interface module and are useful for comparing standard versions and supplied bundle configurations. The digital input and output modules serve different functions and must be selected according to the required electrical signal types.

Dimensions and weights for the I/O modules should be verified against the exact hardware revision and associated BaseUnit before panel layout or procurement.

8.1 How these products work together

A typical distributed automation system consists of a PLC CPU, a PROFINET network, one or more interface modules, and the peripheral modules needed to connect field devices.

The PLC executes the control program and determines the required machine behavior. The interface module manages communication with the remote I/O station. Digital input modules receive signals from switches and sensors, while digital output modules operate compatible loads such as relays, solenoids, and indicator devices.

Analog input and output modules can be added when the application needs to measure or control continuous variables such as temperature, pressure, flow, or motor speed references.

The 6AG2155-6AU01-4BN0 provides the communication link for the distributed station. The exact functionality of the complete system depends on the CPU, peripheral modules, network design, and control program.

9. Installation and Commissioning Recommendations

9.1 Verify the complete order code

The 6AG2155-6AU01-4BN0 is the SIPLUS RAIL ST variant. Do not confuse it with the HF models or with bundles that include a BusAdapter.

Before ordering a replacement, confirm whether the existing installation uses a standalone interface module or a bundle containing the interface module, server module, and BusAdapter.

9.2 Check the power supply

Use a suitable 24 V DC supply and confirm that the voltage remains within the specified 19.2–28.8 V DC range under normal operating conditions.

The power supply must also be sized for the connected I/O modules and other station loads.

9.3 Confirm the BusAdapter and network cable

Select a compatible BusAdapter that matches the physical connection and environmental requirements of the network.

Use suitable industrial Ethernet cabling and follow the network design for shielding, routing, connector installation, and cable length.

9.4 Check the engineering configuration

Confirm that the selected CPU, firmware, engineering software, and peripheral modules support the interface module.

Configure the PROFINET device name and network settings, then verify that the controller recognizes the station and exchanges process data correctly.

9.5 Observe environmental limits

The specified operating range is -40°C to +70°C, with +85°C permitted for 10 minutes under the applicable conditions.

Use an enclosure appropriate for the installation. The module’s IP20 rating does not provide protection against direct water exposure or unrestricted dust ingress.

9.6 Test station operation

During commissioning, verify the supply voltage, network communication, station diagnostics, and operation of each installed I/O module.

Test the machine’s response to communication loss and supply interruption according to the system’s safety and operational requirements.

9.7 Plan maintenance

The module supports single-module hot swapping, but the procedure must follow the supported station configuration and maintenance instructions.

Confirm which modules can be replaced during operation and ensure that the maintenance team understands the required steps before attempting a replacement.

10. Summary

The 6AG2155-6AU01-4BN0 is a SIPLUS ET 200SP IM 155-6 PN ST TX RAIL interface module designed to connect a distributed I/O station to a PROFINET network.

Its key features include a 24 V DC supply, conformal coating, a specified operating temperature range of -40°C to +70°C, a short-duration +85°C condition for 10 minutes under applicable railway conditions, support for up to 32 ET 200SP modules and 16 ET 200AL modules in supported configurations, and single-module hot swapping.

The module measures approximately 50 × 117 × 74 mm and weighs approximately 0.147 kg without a BusAdapter. The listed net weight for the relevant order configuration is approximately 0.170 kg.

The product is particularly relevant to railway-related automation and industrial distributed I/O systems that need PROFINET communication and extended environmental protection.

When selecting or replacing this module, the most important considerations are the exact order code, BusAdapter arrangement, controller compatibility, peripheral-module configuration, environmental conditions, and required maintenance functions.