The IM 155-6 PN ST is the standard PROFINET interface module of the SIMATIC ET 200SP distributed I/O system: it sits at the left end of the station, talks PROFINET to the controller and passes the process image to and from the I/O modules plugged to its right. People usually land on it by order number (6ES7155-6AU01-0BN0, 6ES7155-6AU02-0BN0 and similar) looking for three things: the manual, the GSD file and the right firmware or HSP for their TIA Portal version. This guide explains how the pieces fit together and where each one comes from. For figures (current draw, maximum number of modules, cycle times, temperature ranges) the reference is always the official Siemens equipment manual: we link to it below instead of hosting a copy.
In particolar modo vedremo:
Where to find the official manual
Siemens publishes the equipment manual of the interface module, together with the ET 200SP system manual, on Siemens Industry Online Support. Search for the exact order number printed on the side of your module:
- Siemens Industry Online Support: manuals for 6ES7155-6AU02-0BN0
- Siemens Industry Online Support: all manuals for IM 155-6 PN ST
Download the manual from there rather than from a third-party mirror: Siemens updates it with every hardware or firmware release, and an old PDF can describe limits that no longer match your module. Read two documents together: the equipment manual of the interface module (technical data, LEDs, functions) and the ET 200SP system manual (mounting, BaseUnits, potential groups, wiring rules).
Order numbers: what changes between the variants
The last part of the order number tells you the hardware version and what comes in the box. Before you configure anything, compare the number on the module with the one in your project: a mismatch is the most common reason for a station that refuses to go into data exchange.
| What you see | What it means in practice | What to check |
|---|---|---|
| 6ES7155-6AUxx-0BN0 | Interface module only; the BusAdapter is ordered separately | That you have a BusAdapter (BA 2xRJ45, BA 2xFC or a fibre-optic version) for the cabling you planned |
| 6ES7155-6AAxx-0BN0 | Bundle with accessories in the box | The bundle content listed in the manual or on the packaging |
| AU01 vs AU02 | Different hardware generations of the same module | That your TIA Portal hardware catalog contains the exact version; if not, install the HSP or a newer TIA Portal update |
| Firmware version (e.g. V4.x, V6.x) | Functions available on the device | That the version configured in the project is not higher than the firmware on the module |
GSD file, HSP or hardware catalog: which one you need
These three are often confused, and they solve different problems.
- Hardware catalog of TIA Portal: if you work with a Siemens controller in TIA Portal and your version already lists the exact order number, you need nothing else. Drag the module from the catalog and you get full integration, including module parameters and diagnostics.
- HSP (Hardware Support Package): if the module is newer than your TIA Portal version, the catalog does not show it. Siemens publishes an HSP that adds that module to a specific TIA Portal version. Download it from Industry Online Support, install it with TIA Portal closed, then update the catalog. The HSP is tied to the TIA Portal version: one for V17 does not install on V19.
- GSDML file: you need it when the controller is not configured in TIA Portal (a third-party PROFINET controller, a PC-based controller, another vendor’s engineering tool) or when you deliberately want a generic integration. The GSDML describes the device to any PROFINET engineering tool. Import it into your tool, then configure the modules slot by slot exactly as they are mounted.
Rule of thumb: Siemens controller in TIA Portal, use the catalog or the HSP; anything else, use the GSDML from the same support portal.
Bringing a new station online, step by step
- Mount and wire: interface module with its BusAdapter, then the BaseUnits with I/O modules, and the server module at the right end. The station does not start without the server module.
- Check the potential groups: the first BaseUnit after the interface module, and every BaseUnit that opens a new 24 V supply group, must be the type that feeds a new potential group (light-coloured terminal type); the others pass the supply on. A wrong BaseUnit type shows up as missing supply diagnostics on whole groups of modules.
- Configure the station in the project with the same order numbers, firmware version and slot order as the real hardware.
- Assign the PROFINET device name: online, find the device by its MAC address (printed on the module) and give it exactly the name configured in the project. The controller finds the device by name, not by IP address.
- Download the controller and watch the LEDs. With the station in data exchange the error LED goes off and the I/O modules stop reporting diagnostics.
Firmware updates
Firmware for the interface module is published on the same support portal, searchable by order number. Before updating, read the release notes: they list which hardware versions accept the new firmware and what changes. An update is done online from TIA Portal or with the dedicated Siemens tools, with the station out of production. Afterwards, align the firmware version in the project so that it is not higher than the one on the device: the reverse (project lower than device) is normally accepted, project higher than device is not.
Quick troubleshooting
| Symptom | Most likely cause | First check |
|---|---|---|
| Controller reports the device as missing | Device name not assigned, or different from the project | Online accessible devices: name and MAC address |
| Device found but configuration error | Order number, firmware or slot order differ between project and hardware | Compare module by module, including the server module |
| A group of modules reports missing supply | Potential group not opened by the right BaseUnit, or 24 V not wired to it | BaseUnit type at the start of the group and the supply terminals |
| Module not available in the catalog | TIA Portal older than the module | Install the HSP for your TIA Portal version or update TIA Portal |
| Third-party controller cannot see all slots | Old GSDML or slots configured in a different order | Import the current GSDML and rebuild the slot list |
Frequently asked questions
Can I download the IM 155-6 PN ST manual from this blog?
No. The manual belongs to Siemens and the current version is always the one on Siemens Industry Online Support (links above). This page explains how to use it.
Do I need the GSD file if I use TIA Portal?
Not with a Siemens controller: use the hardware catalog, and the HSP if your TIA Portal version does not list the module yet. The GSDML is for other engineering tools and third-party controllers.
Why does my station not start even though everything is wired?
Check the server module at the end of the station, the device name and that order numbers and firmware in the project match the hardware. Those three cover most first start-up problems.
Where are the technical figures (power, maximum modules, temperatures)?
In the equipment manual of your exact order number. They change between hardware versions, so take them from the manual of your module, not from a generic article.
Related reading on this blog: ET 200SP CPU configuration (Italian) and updating ET200SP firmware in TIA Portal (Italian).
Alessandro Strongoli has been programming PLCs and commissioning machines and plants for many years: S7-1200/S7-1500 with TIA Portal, WinCC panels, SINAMICS drives. Writing here since 2021. About the author
