Siemens 6ES7155-6AU01-0CN0 Distributed I/O

Basic Identification & Model Decoding

Full Designation: SIMATIC ET 200SP IM 155-6 PN/2 HF

6ES7: S7 Distributed I/O Series

155: ET200SP PROFINET Interface Module

6AU01: 2nd-generation 2-port High-Feature (HF) hardware version

0CN0: HF (High Feature) functional variant

Positioning: Head module for ET200SP remote stations, enabling remote I/O expansion via PROFINET for S7-1500 CPUs (1511C / 1513C / 1515 / 1517)

2. Core Hardware Specifications

2.1 Physical Dimensions & Power Supply

2.2 I/O Expansion Capacity

Local backplane: Up to 64 ET200SP signal modules (fully compatible with digital, analog, counter, positioning and safety modules)

Remote extension: Up to 16 ET200AL remote terminal modules

Hot swapping support: I/O modules can be replaced during operation without interrupting station-wide communication

Maximum backplane single-slot load: 1 A / 24 V DC (in conjunction with PM-E power terminals)

2.3 PROFINET Communication Capabilities (Core HF High-Feature Functions)

1. Integrated 2-port switch; BusAdapter is a separately ordered accessory (not included with the base unit)

Optional BusAdapter types: 2×RJ45, 2×M12, 2×FC quick connectors, LC/SCRJ fiber optic, etc.

2. Transmission Rate: 100 Mbps full-duplex, auto-crossing and auto-negotiation
3. Full coverage of real-time protocols:

PROFINET RT (Standard Real-Time)

IRT Isochronous Real-Time: Minimum cycle of 31.25 μs, dedicated for multi-axis motion synchronization

MRP Media Redundancy Protocol (ring self-recovery < 200 ms upon cable breakage)

S2 System Redundancy (dual CPU hot standby for industrial high availability)

Shared Device, PROFIenergy power management, priority startup

4. Maximum PN connections: 16 I/O controllers / HMI hosts

2.4 Front Panel Status LEDs

PWR (Green): 24 V power supply normal

RUN (Green): Module operating correctly

ERROR (Red): Fault indication (communication / backplane / short circuit)

MAINT (Yellow): Maintenance reminder, diagnostic alarm

BusAdapter fitted with dual LINK/ACT port status LEDs

3. Exclusive Advantages of HF High-Feature Version (vs Standard ST Model 6AU01-0BN0)
4. Supports IRT isochronous synchronization and S2 system redundancy (unavailable on standard variant)
5. Complete cable diagnostics, port packet loss statistics, granular channel-level diagnostics
6. Larger backplane address space, compatible with more special function modules (high-speed counters, position input, safety F-modules)
7. Multi-controller Shared Device, priority startup, precision clock forwarding for motion control
8. Enhanced anti-interference and surge protection, ideal for high-reliability production lines in automotive, lithium battery and pharmaceutical industries
9. Mandatory Matching Accessories (Separate Ordering Required)
10. BusAdapter (mandatory; network cables cannot be connected without this adapter)
11. ET200SP Server Terminal Module (installed at the far right end of the station, Part No. 6ES7193-6PA00-0AA0, required to terminate the backplane bus)
12. Various signal base units, PM-E power terminals, digital/analog/counter/safety I/O modules
13. 24 V power terminal plug (supplied as standard with the module)
14. Software Compatibility

Programming Software: TIA Portal V15.1 or higher

Compatible CPUs: Full S7-1500 series, ET200SP Open Controllers

GSDML Version: V2.34, interoperable with third-party PROFINET masters

6. Typical Application Scenarios
7. Automobile Complete Vehicle & Component Production Lines: Multi-axis synchronized welding, conveyor lines relying on IRT isochronous synchronization
8. Lithium Battery & PV Equipment: MRP redundant ring networks, high-availability demand with S2 dual hot standby CPUs
9. Packaging & Injection Molding Machine Tools: Remote expansion of high-speed pulse counter and positioning modules
10. Pharmaceutical & Food Processing Lines: Online hot-swap I/O replacement to minimize downtime
11. Distributed Remote I/O Cabinets for Large Production Lines: Up to 64 modules per station to save cabinet installation space
12. Same Series Model Comparison (Selection Differentiation)

8. Installation & Commissioning Key Points
9. Installation Sequence: DIN rail → IM155-6PN HF base unit → sequential mounting of I/O base modules → server terminal module at the far right end
10. Insert BusAdapter into the upper slot of the module and fasten the locking clip; shield grounding for both ends of network cables
11. IRT Synchronization Applications: Enable isochronous synchronization on the CPU; synchronization domain cycle must match 31.25 / 62.5 / 125 / 250 μs
12. Redundant Ring Network: Activate MRP across the whole line for automatic switchover at ring breakpoints
13. Fault Troubleshooting: Steady red ERROR light → backplane short circuit / missing terminal module; flashing red ERROR light → PROFINET disconnection / IP address conflict
14. Selection Pitfalls to Avoid
15. 0CN0 HF variant is mandatory for motion control, multi-axis synchronization and dual CPU hot standby; the standard 0BN0 model does not support IRT or S2 redundancy
16. BusAdapter must be ordered separately; network port connectors are not pre-fitted to the base unit
17. Missing server terminal module at the station end triggers backplane faults and steady red ERROR LED
18. Derated operation is required at ambient temperatures above +60 °C; reduce the quantity of backplane I/O modules
19. Incompatible with ET200MP interface modules (IM155-5); backplane base units cannot be interchanged

Six Practical Field Application Cases of 6ES7155-6AU01-0CN0 (IM155-6 PN/2 HF)

Exclusive core capabilities of this module: IRT isochronous synchronization, S2 system redundancy, MRP ring network, runtime hot swapping, maximum 64 I/O modules, expansion via up to 16 ET200AL units. All below cases select this HF model for its high-performance features, which cannot be fulfilled by the standard 6AU01-0BN0 variant.

Case 1: Multi-Robot Synchronized Production Line in Automotive Welding Workshop (Core IRT Application)

Project Overview

Main body welding line of a domestic vehicle OEM, controlled by S7-1517T motion CPU. The full line contains 12 remote I/O cabinets, each equipped with one 6ES7155-6AU01-0CN0. Every station carries 48 ET200SP I/O modules (digital input/output, safety F-modules, encoder acquisition), realizing synchronized control with multiple S120 servo drives, KUKA robots and vision cameras.

Network & Functional Design

1. BA 2×RJ45 BusAdapters adopted; full line configured as an IRT isochronous synchronization domain with a minimum cycle of 62.5 μs.
2. Shared system clock for multi-robot welding trajectories, conveyor servos and vision positioning, synchronization error < 1 μs.
3. Linear topology formed by cascading dual ports of each station; local segments built as MRP media redundant rings, with automatic self-recovery within 200 ms upon cable breakage without line shutdown.
4. Supports Shared Device: I/O signals of one station can be read and written simultaneously by the main PLC controller and robot controllers.

Reason for Selecting HF (0CN0) Model

The standard variant lacks IRT function, leading to excessive jitter in multi-axis synchronization and welding offset defects. The HF model delivers precise clock forwarding to meet high-precision automotive welding process standards.

On-Site Benefits

Full-line control cycle reduced from 18 ms to 7 ms, welding reject rate cut by 65%. Faulty I/O modules can be hot-swapped online, cutting single workstation maintenance downtime by 80%.

Case 2: Lithium Battery Stacking Equipment (S7-1500R/H S2 System Redundancy)

Project Overview

Fully automatic stacking machine for new energy power batteries with customer requirement of zero downtime continuous production. Main control adopts S7-1515R redundant CPU; all four remote ET200SP stations deploy 6ES7155-6AU01-0CN0 to collect analog signals of pole piece positioning, correction servos, vacuum suction cups, temperature and pressure.

Redundant Architecture Design

1. S2 System Redundancy (multi-assigned I/O) enabled on each IM155-6 PN HF; two network cables connect to primary and standby redundant CPUs respectively.
2. Seamless takeover of all remote I/O by standby PLC the instant the primary PLC fails, with no signal loss or equipment alarm/shutdown.
3. MRP ring redundancy ensures production continuity despite single-point failures of cables or switches.
4. 64-slot backplane expansion integrates high-speed counter modules to acquire encoder signals from stacking servos.

Key Selection Consideration

The standard 0BN0 model does not support S2 redundancy. Lithium production lines suffer massive scrapping losses once halted, making the HF version compulsory.

Case 3: Aseptic Filling Line for Pharmaceutical Products (Hot Swap + Granular Diagnostics)

Project Overview

Aseptic oral liquid filling line with distributed multi-station I/O, clean environment and frequent format changeovers; full-line shutdown for maintenance is prohibited. The main station uses S7-1511F safety PLC, with 8 ET200SP remote stations fitted with 6ES7155-6AU01-0CN0 paired with safety F-DI/F-DO modules to comply with GMP safety regulations.

Unique HF Field Functions Implemented

1. Full-module runtime hot swap: Faulty valve or sensor I/O modules at filling stations can be directly replaced while the PLC remains running without production stop.
2. Granular channel diagnostics: Precise location of single-channel sensor open circuits or short circuits, with pop-up fault point alerts on HMI.
3. PROFIenergy power saving function automatically cuts backplane I/O power during station standby to reduce energy consumption in clean rooms.
4. Wide temperature operation range of -25 °C ~ +60 °C, suitable for high-temperature control cabinets adjacent to sterilization ovens.

Disadvantages of Standard Variant for Comparison

0BN0 lacks complete channel-level diagnostics, limiting fault localization to the entire station and causing multi-hour troubleshooting delays; fine-grained energy management is unsupported.

Case 4: High-Speed Full-Servo Packaging & Printing Production Line (Short-Cycle Motion Control)

Project Overview

High-speed gravure printing machine for flexible food packaging with 12 servo axes for register control and a maximum printing speed of 300 m/min. Remote I/O cabinets distributed at unwinding, printing, slitting and rewinding stations all adopt IM155-6 PN HF 6ES7155-6AU01-0CN0, paired with S7-1516T CPU.

Core Application Advantages

1. IRT isochronous synchronization delivers accurate multi-color register alignment and eliminates printing ghosting defects.
2. Linear cascading wiring via dual ports reduces the quantity of industrial switches and lowers total cost.
3. Supports extension of up to 16 ET200AL remote terminals close to printing machine rollers, shortening sensor cable runs.
4. High real-time bus achieves lag-free acquisition of encoder pulse signals, with no register offset during high-speed start-stop cycles.

Case 5: MRP Redundant Ring Network for Large Automated Warehouse Logistics

Project Overview

E-commerce automated high-bay warehouse with 16 ET200SP remote I/O stations around racking systems to control stacker cranes, sorting switches, photoelectric sensors and weighing analog signals. All stations use 6ES7155-6AU01-0CN0 to build a complete MRP redundant ring network.

Topology Design

Dual ports of all IM155 HF modules are cascaded end-to-end to form a large ring. Any single cable or interface module fault triggers automatic ring bypass switching; stacker cranes operate continuously without cargo jams. Up to 64 I/O slots per station enable centralized cabinet installation at rack ground level and reduce on-site sub-cabinet count.

Selection Explanation

While standard ST models support MRP, their low bus throughput leads to communication congestion and emergency stops of stacker cranes under concurrent heavy signal loads. The HF hardware doubles bus throughput capacity.

Case 6: Wastewater Treatment Plant Retrofit & Upgrade (Harsh Wide-Temperature Environment)

Project Overview

Retrofit of remote I/O systems for aeration tanks, sedimentation tanks and chemical dosing rooms at a large municipal wastewater plant, replacing legacy ET200M hardware. Outdoor control cabinets face extreme temperature fluctuations and high humidity with condensation. A total of 9 units of 6ES7155-6AU01-0CN0 are deployed to collect dissolved oxygen, pH, liquid level and pump valve signals.

On-Site Adaptation Highlights

1. Wide operating temperature range of -25 °C ~ +60 °C, tolerating subzero winter conditions and high cabinet internal temperatures in summer.
2. 1500 V AC electrical isolation between PN ports and backplane ensures stable communication under heavy interference from water pump inverters.
3. Comprehensive cable diagnostics distinguish sensor open circuits, cable aging and ground faults.
4. Fanless passive cooling eliminates dust accumulation failures in high-humidity wastewater environments, with MTBF exceeding 120,000 hours.

General Selection Summary (Mandatory Scenarios for 6AU01-0CN0 HF Model)

1. Applications requiring IRT isochronous synchronization: multi-axis servo drives, robots, printing presses, lithium battery stacking equipment
2. S7-1500R/H redundant systems requiring S2 multi-assigned I/O
3. MRP redundant ring topologies where production line shutdown is unacceptable
4. Demand for online hot swapping of I/O modules and granular single-channel diagnostics
5. Multi-controller Shared Device I/O sharing and PROFIenergy energy management
6. High-density stations (over 32 I/O modules per station, with ET200AL remote extensions)