ET200S vs ET200SP: Selecting Distributed I/O for S7-1200 PROFINET

Overview

The SIMATIC ET200S and SIMATIC ET200SP are two generations of modular, IP20 distributed I/O systems designed for cabinet-mounted operation behind a SIMATIC controller. Both are PROFINET-capable, both connect as I/O devices to an S7-1200 CPU such as the 6ES7214-1AG40-0XB0 (CPU 1214C DC/DC/DC), and both expose the same logical channel image to the controller through a GSD file imported into TIA Portal. They differ in mechanical footprint, power structure, diagnostic depth, module catalog, and lifecycle status.

The ET200S is the legacy platform; the ET200SP is the current platform and the recommended choice for new machines. Both are still maintained for spare-part and migration scenarios, but new projects should be specified against the ET200SP catalog. The product overview PDF from Siemens (re-hosted on the Digi-Opus catalog portal) summarizes the position:

SIMATIC ET 200SP Catalog and Overview (PDF) — "a multi-functional and finely scalable distributed I/O system ... about 50% narrower than" the prior generation.

System Architecture: ET200S

The ET200S is built around a backplane that accepts one Interface Module (IM) followed by a stack of I/O modules terminated by a terminating module. The IM is the only fieldbus gateway in the station; everything downstream is backplane I/O. Key architectural properties:

• IM variants: PROFIBUS IM151-1 (6ES7151-1BA02-0AB0), PROFINET IM151-3 PN (6ES7151-3BA23-0AB0), and PROFINET IM151-3 PN HF (high-feature, 6ES7151-3BA23-0AB0 family) — verify the exact order suffix in the current Siemens Online Help for your firmware target.
• Power structure: PM-E power modules feed 24 V and load-voltage into the backplane. The PM-E sits after the IM and before any digital output or analog output modules that require a separate load group.
• Channel density: Standard DI/DO modules are 15 mm wide with up to 4 or 8 channels; analog modules are 15-25 mm wide.
• Configuration: Each module position is fixed; modules are inserted left-to-right with a terminator at the end of the rack.

System Architecture: ET200SP

The ET200SP replaces the screw-in ET200S backplane with a click-in BaseUnit system. Every I/O module plugs onto a BaseUnit (BU), and the BaseUnit carries the backplane contacts and the load-voltage distribution.

• IM variants: IM155-6 PN ST (standard, 6ES7155-6AU01-0BN0), IM155-6 PN HF (high-feature, supports shared device, MRP, MRPD, isochronous mode, 6ES7155-6AU00-0BN0), IM155-6 PN BA (basic, lower-cost, fewer slots), and PROFIBUS IM155-6 DP ST (6ES7155-6BA00-0BN0). Confirm the firmware version required for the desired PROFINET conformance class.
• BaseUnits (BU): Type A0 (no AUX terminal, no voltage group feed-through), Type A1 (AUX terminal, no feed-through), Type B0 (new load group, feed-through), Type B1 (new load group + AUX). The baseunit type controls how 24 V and load voltage are routed between adjacent modules.
• Channel density: Standard digital modules are 15 mm wide with 8 or 16 channels; analog modules are 15 mm wide; the overall station is approximately 50% narrower than the equivalent ET200S station.
• Color-coded labeling: Each module uses a color code on the slot and on the side of the module (CCxx) to prevent wrong-insertion; the BU label set is also color-coded by voltage group.

ET200S vs ET200SP Feature Comparison

S7-1200 CPU 1214C Compatibility

The S7-1200 CPU 1214C is a PROFINET IO Controller with a single PROFINET port on the CPU body. The PROFINET port on the CPU is the only network interface available for connecting PROFINET IO devices; there is no integrated PROFIBUS port and no PROFIBUS module add-on for the S7-1200. Therefore, when connecting ET200S or ET200SP, the choice of fieldbus is effectively PROFINET.

• CPU 1214C PROFINET variant (firmware V4.x and later) acts as PROFINET IO Controller per IEC 61158 / PROFINET specification, conformance class A; the PROFINET port supports real-time class 1 (RT) and, with CPU firmware V4.2 and TIA Portal V14 SP1+, real-time class 2/3 (IRT) where the IO device supports it.
• Direct-attach architecture: Both ET200S and ET200SP are wired directly to the CPU's PROFINET port via a managed or unmanaged switch. A typical cabinet topology uses a SCALANCE XC switch between the CPU and one or more I/O stations.
• Maximum IO devices: The CPU 1214C supports up to 16 PROFINET IO devices. Both ET200S and ET200SP count as a single IO device each, regardless of slot count.
• Device configuration in TIA Portal: IM155-6 PN ST and IM155-6 PN HF are imported via GSDML file; the IM155-6 PN BA is supported natively in TIA Portal V14 SP1 and later without an external GSD import. ET200S IM151-3 PN modules are similarly imported through GSDML or selected from the catalog if the HSP is installed.

Interface Module (IM) Selection

The IM is the gateway between the fieldbus (PROFINET or PROFIBUS) and the backplane. Choose based on the fieldbus, the required feature set, and the available firmware on the CPU.

I/O Module Catalog Highlights

Both platforms share the same channel-level interface to the S7-1200 (process image, value status, channel diagnostics). The catalog however differs.

The ET200SP catalog is the active catalog and continues to receive new modules; the ET200S catalog is in maintenance. For new builds, prefer the ET200SP catalog unless a legacy module type is required.

PROFINET Topology and Cabling

Wiring between the CPU 1214C PROFINET port and the ET200S/ET200SP IM uses standard RJ45 patch cabling. Use Cat 5e or higher, industrial-grade, with M12 D-coded connectors at the cabinet cable entry for vibration-tolerant installations.

• Star topology: Each IM connects to a port on a managed switch (e.g., SCALANCE XC206-2SFP). The CPU 1214C and the switch sit on the same subnet. This is the most common topology for cabinet-internal wiring.
• Linear topology: ET200SP IM155-6 PN ST and HF support the PROFINET device as a 2-port switch; you can daisy-chain them. The ET200S IM151-3 PN variants also act as 2-port switches in linear topology. Linear is convenient for distributed cabinets but requires all devices to be PROFINET conformant.
• MRP / MRPD: Use Media Redundancy Protocol only with a managed switch acting as MRP manager. IM155-6 PN HF supports MRPD (seamless redundancy) for high-availability lines.
• Cable length: Up to 100 m between two devices per PROFINET specification; copper only. For longer distances use SCALANCE media converters or fiber modules (SFP).

TIA Portal Configuration Procedure

Configure both ET200S and ET200SP as PROFINET IO devices under the CPU 1214C in TIA Portal. The procedure is similar; the differences are in catalog selection and slot counts.

1. Add CPU 1214C to the project from the device catalog. Match the firmware version to the CPU's actual firmware (read from the CPU's online diagnostics under "Online & Diagnostics" > "Identification").
2. Open the PROFINET port on the CPU (X1) in the device view. Confirm the IP address (default 192.168.0.1, mask 255.255.255.0) and device name (default s7-1200). Device name must be unique on the subnet for PROFINET LLDP discovery.
3. Install the matching HSP (Hardware Support Package) for ET200SP from the Siemens Support site (entry ID 109751706 is the consolidated TIA Portal HSP collection; verify the latest in your TIA Portal installation). For ET200S, the older HSP is required if your TIA Portal is V14+.
4. Add the IM from the catalog (Devices & Networks > Network view > drag the IM into the rack view). The IM appears as a new IO device. Connect its PROFINET port to the CPU PROFINET port. TIA Portal assigns an IP and a device name.
5. Populate the station by dragging I/O modules from the catalog into the IM's rack in the same slot order as the physical build. The first slot after the IM is slot 1; the BaseUnit or backplane slot number is fixed.
6. Set the device name on the IM physically via TIA Portal "Assign PROFINET device name" or via PRONETA / Topology Editor. The device name must match the configured name exactly, including case.
7. Compile and download the hardware configuration to the CPU. The CPU will establish PROFINET AR (application relationship) to each IM; the IM will then negotiate slots.
8. Verify in the Online & Diagnostics view that the IO device status is "OK" and that each module reports "No fault".

Hardware Configuration Rules

• Slot rules — ET200S: Maximum slot count depends on the IM. PM-E power modules occupy slots like any other module but are not addressable; they configure the load group. End the rack with a 6ES7193-4JA00-0AA0 terminating module.
• Slot rules — ET200SP: Maximum slot count depends on the IM: BA = 12, ST = 32, HF = 64. Insert a server module (6ES7155-6AU00-0CN0 family) in the last slot to terminate the backplane and hold the cover. The first BaseUnit must be type A0 or A1 (after the IM) unless your configuration requires a B-type in slot 1; the BU type after that controls whether the next module is in the same load group.
• Load group sizing: Each load group can source up to 10 A continuous on the load-voltage rail; verify the digital output module's total continuous current against this limit. For ET200SP use BU type B0/B1 to start a fresh group.
• Derating: Both platforms require derating above 40 °C horizontal mounting or 50 °C vertical mounting. Derate analog modules per module datasheet; digital output modules typically derate to 0.5 A at 60 °C.

Migration: ET200S → ET200SP

Migration is usually driven by spare-part availability or by a desire to consolidate onto the current platform. It is mechanical and electrical work, plus software re-work.

1. Inventory the existing ET200S rack: Capture module order numbers, slot positions, and the IO addresses in the S7-1200 project. Export the S7-1200 hardware configuration from TIA Portal.
2. Map each ET200S module to its ET200SP equivalent. For most DI/DO and AI/AO modules there is a direct replacement in the ET200SP catalog. For specialty modules (e.g., 1Count24V, SSI, old pneumatic valve modules) verify availability; some legacy types were not migrated.
3. Plan the cabinet layout: The ET200SP rack is approximately 50% narrower, so the new station will fit a shorter DIN section. You may need to relocate the existing station.
4. Select the IM: Replace IM151-3 PN with IM155-6 PN ST (typical) or HF (if shared device or isochronous was used). Re-import the new GSDML file into TIA Portal.
5. Rewire power: ET200S used PM-E power modules; ET200SP uses BU type B0/B1 to define load groups. Re-wire the load-voltage feed and AUX terminal to the new BUs.
6. Re-assign addresses: ET200SP module I/O addresses are configurable per slot. Reassign to match the original S7-1200 program addresses if possible, otherwise update the program to the new addresses.
7. Download and verify: As in the TIA Portal configuration procedure above.

Troubleshooting Matrix

Selection Recommendations

• New machine build: Specify ET200SP with IM155-6 PN ST as default. Add IM155-6 PN HF only if shared device, isochronous, or MRPD is required.
• Cost-optimized small station (≤12 slots, RT only): IM155-6 PN BA is appropriate.
• Existing ET200S station, no spare parts available: Plan a migration; do not stock new ET200S modules long-term.
• PROFIBUS only available on a legacy line: Stay on ET200S (IM151-1 DP). For a new PROFIBUS station the ET200SP IM155-6 DP ST can be considered, but on the CPU 1214C path PROFINET is the only fieldbus option.
• Motion / isochronous / Safety: ET200SP IM155-6 PN HF with F-modules in the ET200SP catalog. CPU 1214C supports PROFIsafe via the IO device, not via the local CPU.

Verification Checklist

1. CPU 1214C PROFINET port link LED is green; the port speed autonegotiates to 100 Mbit/s full duplex (PROFINET requirement).
2. IM reports its assigned PROFINET device name and IP via TIA Portal online view; the device's MAC address matches the physical label.
3. Every slot in the IM's TIA Portal configuration matches a physically inserted module of the same order number and firmware version.
4. Each output channel can be forced in TIA Portal and the corresponding field voltage is present at the load terminal.
5. Each input channel toggles when the field device is actuated and the corresponding bit in the process image reflects the change within the configured update time.
6. Diagnostic buffer on the IM contains no entries after the station has been operating under load for at least one hour.
7. Power group current draw on each BU type B0/B1 load group is below the 10 A continuous limit; verify with a clamp meter on the load feed.

References (linked inline)

Documentation references cited in this article:

• SIMATIC ET 200SP Catalog and Overview (PDF)
• Siemens Industry Online Support — search entry "ET 200SP" and "ET 200S" for manuals, GSDML files, HSPs, and firmware.
• Siemens Industry Mall — order number validation, configurators, and the SIMATIC Selection Tool.