Configuring ET200M with Two IM153-2 in PCS7 v9.1 HWConfig

Problem Overview

When configuring a Siemens PCS 7 v9.1 redundant automation system with two S7-400H CPUs (CPU 414-5H) and redundant CP 443-1 communication processors, engineers frequently encounter an HWConfig limitation: it appears that two IM 153-2 interface modules cannot be placed side-by-side in a single ET 200M rack in HWConfig. This problem surfaces when the I/O is intentionally not redundant—only the controllers and the PROFIBUS DP master systems are redundant—yet the engineer still wants both IM 153-2 modules to be visible in the same physical I/O rack for documentation and maintenance reasons.

The error manifests as a grayed-out slot, an “Invalid configuration” warning in the SIMATIC Manager diagnostic buffer, or HWConfig silently refusing to insert a second IM 153-2 in the same rack object. The underlying reason is that HWConfig enforces a 1:1 mapping between an ET 200M station and a single PROFIBUS DP master system. To place two IM 153-2 modules “side by side” in HWConfig, each module must belong to a different DP master system, which in turn means each one must be drawn under a different CPU (CPU 0 or CPU 1) of the H-station.

Target System Architecture

The configuration described in the field case is a classic S7-400H redundant cell with PROFIBUS DP distributed I/O. The required topology is summarized below:

Root Cause: HWConfig Rack Constraints

HWConfig models an ET 200M station as a single PROFIBUS DP slave attached to exactly one DP master system. Internally, the rack object is the slave's slot frame: slot 0 is reserved for the IM 153-2 itself, slot 1 is the power supply (if present), and slots 2 through 11 (or up to 12 with the wide rack) accept S7-300 I/O modules.

When you attempt to drag a second IM 153-2 into the same rack object, HWConfig rejects the operation because the rack already has a slave identity. The PROFIBUS DP standard (IEC 61158 / IEC 61784) only allows one station address per physical slave, and SIMATIC Manager enforces this rule in the GSD-based station view.

The user-visible result is the perception that “HWConfig does not let me place two IM 153-2 modules beside each other in one rack.” The correct mental model is that there are two racks in HWConfig—one per DP master system—even though physically both modules may share the same ET 200M mounting rail and the same set of backplane wiring. The HWConfig representation differs from the physical layout.

Resolution: Configure Two Independent ET 200M Stations

The resolution is to add two independent ET 200M slave objects in HWConfig, one connected to the DP master system of CPU 0, the other connected to the DP master system of CPU 1. The following procedure applies to PCS 7 v9.1 (and is structurally identical back to PCS 7 v8.x). It is the configuration pattern Siemens Support documents under Entry ID 109756485 – S7-400H with ET 200M configuration.

Prerequisites

• SIMATIC Manager with PCS 7 v9.1 SPx installed (HF installation recommended for the S7-400H F-library compatibility).
• HWConfig catalog populated with the IM 153-2 GSD files. For an IM 153-2BA10 (PROFIBUS DP-V0) the GSD file is part of the standard catalog. For IM 153-2BB00 or later (BX30) used with H-systems, install the corresponding hardware support package (HSP) shipped with PCS 7 v9.1.
• CPU 414-5H V6.0 or higher (CPU firmware V6 is the recommended baseline for the redundant operating modes used with PCS 7 v9.1; V5 firmware is end-of-life and not supported by PCS 7 v9.1).
• Two DP master systems already configured in HWConfig (DP1 on CPU 0, DP2 on CPU 1), and at least one PROFIBUS bus line drawn in the H-station.

Step-by-Step Configuration

1. Open the S7-400H station in HWConfig via SIMATIC Manager (right-click the H-station → Open Object → HWConfig).
2. Confirm that the H-station has been inserted with the correct type (S7-400H with sync module slot). The slot frame of the H-station has two CPU rows (R0 and R1) plus CP 443-1 slots.
3. Locate the DP master system on the CPU 0 side. Right-click the DP interface of CPU 0 (slot 3, IF1) → Add Master System. Confirm the default PROFIBUS address 2 and baud rate 1.5 Mbit/s (or 12 Mbit/s for short-distance racks).
4. Add a second DP master system on the CPU 1 side in the same way. Use a different PROFIBUS address on the master side (e.g., 3) and the same baud rate as DP1.
5. Open the HWConfig catalog (View → Catalog) and navigate to PROFIBUS DP → ET 200M. Drag the IM 153-2 (e.g., 6ES7153-2BA10-0XB0 for BA10, or 6ES7153-2BB00-0XB0 for BB00) onto the DP master system of CPU 0. Assign PROFIBUS address 4.
6. Open the Object Properties of the IM 153-2 (double-click the module). Switch to the “Redundancy” tab. In PCS 7 v9.1 with H-systems, the option “Connect to 2 DP master systems” becomes available only if the GSD supports redundant operation. For a non-redundant I/O cell, leave this option cleared. Confirm with OK.
7. Add the S7-300 signal modules to the slots of this first ET 200M. Slots 0 (IM 153-2), 1 (PS 305/307 if used), 2–11 (SM modules).
8. Drag a second IM 153-2 of the same type from the catalog onto the DP master system of CPU 1. Assign PROFIBUS address 5.
9. Configure the redundancy tab of the second IM 153-2 in the same way (cleared, since the I/O is not redundant). Populate the S7-300 modules in slots 2–11.
10. Save and compile the HWConfig (Station → Save and Compile). Confirm that the diagnostic buffer reports no errors.

What the User Will Now See in HWConfig

Instead of “one rack with two IM 153-2 modules”, the engineer will see two separate ET 200M stations in the project tree, each with its own DP master system. The PROFIBUS topology view shows two DP lines emerging from the H-station—one to the left (CPU 0), one to the right (CPU 1). The NetPro view confirms the redundant H-station and the two DP master systems.

Object Properties: Redundancy Tab

The “Redundancy” tab in the IM 153-2 object properties dialog is the control point for switching a slave from single-master to dual-master operation. The available settings are summarized below:

Verification

After saving and compiling HWConfig, perform the following verification checks:

1. Open the diagnostic buffer of the S7-400H station. There must be no entries of type “Station failure”, “Slave not found”, or “Parameter error”.
2. In NetPro, confirm that both DP master systems are listed under the H-station and that both are bound to the active CPU. The redundant binding is automatic; PCS 7 propagates the DP configuration from the active CPU to the standby CPU at link-up.
3. Download the HWConfig to the H-station (Target System → Download). The H-system will perform a link-up; expect a brief RUN-REDU → RUN-SOLO transition.
4. On each physical IM 153-2, the SF and BF LEDs should extinguish after parameterization. A persistent BF LED indicates a baud-rate mismatch or a missing termination on the PROFIBUS segment.
5. From the H-station, use a PG/PC with SIMATIC Manager connected to either CPU and read the module status of the two ET 200M stations (Accessible Nodes, or PLC → Module Information). Both must report “OK”.
6. Test the redundancy switchover: trigger a STOP → RUN on the active CPU, or pull the active CPU's power and observe that the standby CPU takes over, re-parameterizes both DP master systems, and brings the I/O back into process. The expected switchover time is < 100 ms for the CPU redundancy; the I/O comes back within 1–2 s after the new active CPU re-initializes the PROFIBUS.

Troubleshooting Matrix

Reference: IM 153-2 Variants Relevant to S7-400H

For the engineer's reference, the IM 153-2 product line relevant to S7-400H systems is summarized below. Always confirm the exact order number against the current Siemens catalog and the project's hardware list.

Field-Proven Caveats

• In PCS 7 v9.1 the HWConfig catalog must be populated with the IM 153-2BB00 / BX30 entry from the matching HSP. If the entry is missing, install the HSP shipped with the PCS 7 v9.1 DVD set before opening HWConfig.
• The two ET 200M stations in this configuration are not redundant. If the active CPU fails, the DP master on CPU 0 (or CPU 1) takes over, but the ET 200M on the failed side is no longer reachable until the original CPU is restored. This is the intended behavior for cost-optimized cells where I/O availability is not safety-critical.
• For applications that require redundant I/O, the IM 153-2BB00 / BX30 in object-property mode “Connect to 2 DP master systems” allows the same physical module to be reached by both CPUs. The slave is then configured twice in HWConfig (once per DP master system) but maps to the same PROFIBUS address and the same set of I/O channels.
• CFC charts in PCS 7 v9.1 will see a single process image; the I/O driver block (CH_AI, CH_DI, etc.) is bound to the symbolic I/O address of the active CPU's DP master. There is no driver-level change required when moving from a single DP master to two DP masters; only the I/O address prefix differs.
• Avoid mixing IM 153-2BA10 and IM 153-2BB00 in the same redundant cell. The GSD files differ in their parameterization services, and the H-system's link-up will report a configuration mismatch.
• When terminating the PROFIBUS segments, place the active terminator at the physical ends of each DP line. S7-400H systems with two DP masters in the same rack benefit from external terminators rather than the on-board PROFIBUS terminator, especially at 12 Mbit/s.
• After every HWConfig change, run a full “Save and Compile” with the option to update the S7 program as well. PCS 7 v9.1 sometimes leaves stale address entries in the symbol table if the compile step is skipped.

Comparison: Single-Sided vs Redundant I/O in S7-400H

Summary

The “two IM 153-2 in one rack” requirement is satisfied in HWConfig by configuring two independent ET 200M stations, each on its own DP master system attached to one of the two H-CPUs. The physical mounting can remain as originally planned; the HWConfig representation is what must be corrected. The redundancy tab in the IM 153-2 object properties is only meaningful for redundant I/O cells; for single-sided I/O in an S7-400H station, leave the option cleared and rely on the H-system's controller-level redundancy to keep the process running through a CPU switchover.

FAQ