Mapping PCS 7 Hardware Bundle Order Numbers (MLFBs) to HW Config - Steel vs Aluminum Backplane Racks

When configuring an automation station in SIMATIC PCS 7 Hardware Configuration (HW Config) and attempting to match a commercial Bundle Order Number (such as 6ES7654-6CP00-4GF1 featuring a steel mounting plate) against the catalog wizard, the specific bundle number may not appear because Siemens Bundle MLFBs represent procurement packages rather than physical electronic modules. In HW Config, backplane racks are modeled by their individual physical rack MLFBs (e.g., standard Universal Rack UR2). Electrically and logically, steel base plate racks and aluminum base plate racks share identical bus backplanes and slot addressing. To resolve configuration discrepancies, configure the standard rack and CPU via the wizard or insert them manually, then right-click the rack in HW Config -> 'Exchange Object...' to select the precise individual rack MLFB.

Commercial Procurement Bundles vs Physical HW Config Components

In industrial project engineering, electrical drafting departments order automation hardware using Siemens Pre-Assembled System Bundles (such as pre-assembled AS bundles like 6ES7654-6CP00-4GF1 for AS 410 or classic S7-400 systems). A single bundle order number consolidates multiple physical hardware elements: a 9-slot or 18-slot rack, redundant or single power supplies, backup batteries, a CPU, runtime capacity expansion cards, and mounting base plates.

A frequent point of confusion arises when the automation engineer opens SIMATIC Manager and launches HW Config:

The engineer searches for the exact bundle number (e.g., 6ES7654-6CP00-4GF1) and finds that the catalog wizard only lists -3GF1 or does not display the bundle number at all.
The Architectural Reason: HW Config is a microprocessor execution tool, not a procurement catalog. Microprocessor firmware communicates with physical silicon modules—CPUs, CPs, and interface ASICs. Consequently, HW Config catalogs operate strictly at the level of individual component MLFBs (e.g., CPU 6ES7410-5HX08-0AB0, Rack 6ES7400-1TA01-0AA0).

Deciphering the Bundle Order Number Structure (Steel vs Aluminum Plates)

The differences between bundle suffixes often denote mechanical mounting variants rather than electronic logic:

-3GF1: AS Pre-assembled system mounted on an Aluminum base plate (lightweight, standard industrial environments).
-4GF1: AS Pre-assembled system mounted on a Steel base plate (high mechanical rigidity, seismic vibration resistance, heavy-duty marine/offshore environments).
Both variants utilize the exact same internal subrack (such as the Universal Rack UR2 or CR3). The backplane bus circuit boards, connectors, power supply rails, and slot numbers (Slots 1 to 9) are 100% identical.

Backplane Bus Compatibility: Why Racks Share Identical Logical Drivers in HW Config

Because the backplane bus architecture is identical regardless of plate material:

The S7-400 P-bus (Peripheral bus) and C-bus (Communication bus) function identically on steel and aluminum assemblies.
In HW Config, selecting the standard aluminum bundle template automatically configures the correct rack type, CPU slot, and power supply slot.
If electrical CAD documentation requires absolute MLFB matching in HW Config reports, the engineer can use the 'Exchange Object...' function to align the specific subrack MLFB.

Identifying Pre-Assembled CPUs and System Expansion Cards within Bundles

When a bundle wizard generates a station, engineers often wonder which specific CPU model and capacity card have been instantiated:

In SIMATIC Manager, the wizard reads the internal bundle breakdown table and places the corresponding CPU in Slot 3 (or Slot 4).
For the CPU 410-5H, the bundle MLFB dictates the initial Process Object (PO) capacity embedded in the System Expansion Card (SEC) (e.g., 500 PO, 1000 PO, or 2000 PO).
In HW Config, double-clicking the CPU opens Object Properties, where the physical CPU MLFB and firmware revision are explicitly displayed.

Comparative Hardware Matrix: Commercial Bundle MLFB vs HW Config Physical MLFBs

The following table demonstrates how a commercial procurement bundle maps to discrete physical hardware entries in HW Config:

Commercial Bundle ItemCommercial MLFBPhysical HW Config ComponentIndividual Physical MLFBHW Config Rack SlotPre-Assembled Bundle6ES7654-6CP00-4GF1N/A (Procurement Container)N/AN/ASubrack (Steel Plate)Included in BundleSubrack UR2 (9 Slots)6ES7400-1TA01-0AA0Rack FramePower Supply ModuleIncluded in BundlePS 407 10A (120/230VAC)6ES7407-0KR02-0AA0Slot 1 & 2Process ControllerIncluded in BundleCPU 410-5H PA V8.26ES7410-5HX08-0AB0Slot 3System Expansion CardIncluded in BundleSEC PO 10006ES7653-2CC00-0XB0CPU Rear Slot (Firmware)

Commercial Accuracy Disclaimer

Commercial Accuracy Disclaimer: Software order numbers (MLFBs), package structures, and hardware capacity prerequisites vary across PCS 7 versions and hardware platforms. System integrators must confirm exact software entitlements and licensing requirements against the official Siemens Catalog CA 01 and obtain an authorized Siemens distributor quotation prior to purchasing.

Hardware bundle numbers change across catalog cycles. Always cross-reference the breakdown of bundle packages in the Siemens Industry Mall or CA 01 catalog to confirm individual component part numbers before finalizing cabinet electrical designs.

Step-by-Step Procedure to Configure and Exchange Bundle Hardware in HW Config

Follow this procedure to configure bundled hardware accurately in HW Config:

Create Station via Wizard or Manual Insertion:
- In SIMATIC Manager, select Insert > Station > SIMATIC 400 Station.
- Double-click Hardware to open HW Config.
Insert Equivalent Subrack:
- In the hardware catalog, expand: SIMATIC 400 > RACK-400.
- Select the rack matching your bundle size (e.g., UR2 for 9-slot or UR1 for 18-slot).
- Drag the rack into the configuration window.
Insert Power Supply and CPU:
- Drag the matching power supply (e.g., PS 407 10A) into Slot 1.
- Expand CPU 410 > CPU 410-5H and drag the CPU into Slot 3.
Exchange Subrack Object (If Exact MLFB Alignment Required):
- Click on the outer border frame of the rack.
- Right-click and select Exchange Object....
- The catalog opens filtered to compatible subracks; select the exact subrack MLFB specified on your hardware delivery note.
- Click OK to swap while preserving all seated modules.
Save and Compile:
- Click Save and Compile (Ctrl+S). Confirm zero errors.

Verification

Verify hardware configuration accuracy through these checks:

In HW Config, verify that all seated cards (PS, CPU, CPs) display green status without red exclamation marks.
Double-click the CPU: confirm that the MLFB displayed matches the physical label on the delivered CPU module.
Connect the Engineering Station to the AS CPU via Industrial Ethernet.
Execute Target System > Download to Module... in HW Config. Verify that the hardware configuration downloads successfully without rack parameter faults.

Limitations and Operational Precautions

Redundant S7-400H Racks: In fault-tolerant (H) systems, ensure both racks in the redundant pair utilize identical subrack types and identical CPU firmware revisions.
Power Supply Sizing: When calculating cabinet heat dissipation, ensure power supply models match physical cabinet thermal calculations.
System Expansion Card Verification: While HW Config configures the CPU, verify the physical SEC card PO capacity in CPU Module Information (Ctrl+D) online before commissioning.

Engineer FAQ

Why can't I find my bundle MLFB (such as 6ES7654-6CP00-4GF1) in HW Config?

Bundle numbers such as 6ES7654-6CP00-4GF1 are commercial packaging codes. HW Config only catalogues the individual physical electronic components (6ES7410-..., 6ES7400-..., 6ES7407-...).

Is there any functional difference between a steel plate and an aluminum plate rack?

No. Electrically, logically, and software-wise, they are 100% identical. The difference is purely mechanical rigidity and mounting plate material.

Can I exchange a 9-slot rack for an 18-slot rack using 'Exchange Object'?

No. 'Exchange Object' only works between subracks of identical slot capacity. To change from 9-slot to 18-slot, you must insert a new UR1 rack and move the modules.

Where can I find the exact component breakdown of a Siemens bundle?

The component breakdown is listed in the Siemens Industry Mall under the bundle's product details or in the PCS 7 Catalog ST PCS 7.

What is a UR2 subrack?

The UR2 (Universal Rack 2) is a 9-slot S7-400 subrack supporting both central processing and distributed communication cards on the P-bus and C-bus.