Resolving 'Connected CPU Has Rejected the Load Order' on CPU 410-5H in SIMATIC PCS 7 - Driver Library and Firmware Compatibility

In SIMATIC PCS 7, the error 'The connected CPU has rejected the load order' occurring at approximately 6% of the AS program download progress on a CPU 410-5H (6ES7410-5HX08-0AB0) indicates that the controller firmware has rejected incompatible system blocks, obsolete driver libraries, or invalid system function calls (SFCs/SFBs). When migrating older projects from PCS 7 v7.x or v8.0 to a CPU 410-5H, retaining legacy V7 driver blocks causes download rejection because the CPU 410-5H requires modern PCS 7 Basis Library drivers (V8.1 or higher). To resolve this, upgrade the driver blocks in the Master Data Library to match the CPU 410 release and recompile with module driver generation.

CPU 410-5H Firmware Architecture and Load Order Validation

The SIMATIC CPU 410-5H (6ES7410-5HX08-0AB0 / 6ES7410-5HX08-4AB0) is Siemens' dedicated flagship controller for SIMATIC PCS 7. Unlike standard S7-400 CPUs (e.g. CPU 417-4H), the CPU 410-5H operates a modern high-performance firmware architecture (Firmware V8.0, V8.1, V8.2) designed specifically to work with modern PCS 7 system libraries.

When an engineer initiates a program download from SIMATIC Manager:
* At approximately 6% download progress, the programming package transfers the core system blocks, organization block table, and hardware-specific system function calls (SFCs / SFBs).
* The CPU 410-5H firmware validates these blocks against its internal firmware execution tables.
* If the incoming program contains obsolete system blocks from older PCS 7 releases (e.g. legacy V7.0/V7.1 driver blocks or retired SFCs), the CPU firmware rejects the download order to protect controller memory from fatal microkernel halts.

Root Causes of Download Rejection at 6% Progress

The specific root causes that trigger download rejection on CPU 410-5H:
1. Migration 'Without Utilization of New Functions': In legacy project migrations (e.g. v7.0/v7.1 -> v8.0 SP2 / v8.2), engineers often select the migration option 'Without utilization of new functions' to avoid changing block types. However, inserting a CPU 410-5H is fundamentally a hardware replacement that mandates new functions.
2. Legacy Driver Blocks in Master Data Library: Driver blocks from PCS 7 V7.1 (e.g. MOD_D1, CH_AI, PA_CPU, OB_BEGIN) contain SFC calls that do not exist or have different signature checks in CPU 410-5H firmware.
3. Corrupted or Obsolete Global Data Blocks: Old global DBs created in STEP 7 V5.3/V5.4 may contain header attributes or memory alignment structures incompatible with CPU 410-5H 64-bit alignment.

Remediation - Upgrading Basis Library Drivers and Cleaning Old Blocks

To eliminate load order rejection and enable clean downloading to CPU 410-5H:

[Phase 1: Update Master Data Library with Compatible Drivers]
   │  • Open: File -> Open -> Libraries -> "PCS 7 Basis Library V8.1" (or V8.2)
   │  • Copy the following core driver blocks into your Multiproject Master Data Library:
   │      - MOD_D1, MOD_D2, MOD_HA, MOD_CP
   │      - CH_AI, CH_AO, CH_DI, CH_DO
   │      - OB_BEGIN, OB_END, DIAG_INF
   │
[Phase 2: Update Block Types in CFC]
   │  • In SIMATIC Manager: Open CFC Editor
   │  • Select: Options -> Block Types...
   │  • Select your Master Data Library as the source
   │  • Click "Clean Up" to purge unreferenced legacy blocks
   │  • Select all updated Basis Library blocks -> Click "New Version..."
   │  • Confirm the update across all charts in the S7 Program
   │
[Phase 3: Recompile Hardware and Software]
   │  • In HW Config: Execute "Station -> Save and Compile" -> Download HW Config
   │  • In CFC: Select "Chart -> Compile -> Changes Only" (or Entire Program)
   │  • Ensure "Generate module drivers" checkbox is checked!
   │  • Execute PLC -> Download -> Entire Program -> CPU 410 accepts the load order!

Procurement Notice: Validate all final license quantities, media packages, and part numbers against current Siemens Industry Mall catalogs and with an authorized Siemens distributor quotation prior to procurement.

CPU 410-5H System Compatibility and Driver Block Matrix

Compare driver library compatibility across SIMATIC PCS 7 controller generations:

Controller HardwareMLFBMinimum PCS 7 ReleaseDriver Library CompatibilityRejection at 6% ProgressCPU 417-4H (Legacy)6ES7417-4HL04-0AB0PCS 7 v6.0 - v7.1PCS 7 Standard Library V7.xAccepts V7 legacy driversCPU 417-5H6ES7417-5HT06-0AB0PCS 7 v7.1 SP3 - v8.2Basis Library V7.1 / V8.0Compatible with V7.1 driversCPU 410-5H Standard6ES7410-5HX08-0AB0PCS 7 v8.1 (or v8.0 SP2)Basis Library V8.1+ RequiredRejects V7.x Driver BlocksCPU 410 SMART6ES7410-5HN08-0AB0PCS 7 V8.1 SP1 AsiaBasis Library V8.1+ RequiredRejects V7.x Driver Blocks

Verification

To confirm that the CPU 410-5H accepts the software download:
1. In STEP 7 SIMATIC Manager, select the AS Station -> PLC -> Download.
2. Observe the download progress bar; confirm that the progress moves past 6% without error dialogs.
3. Verify that the entire block transfer reaches 100% and prompts to switch the CPU to RUN mode.
4. Open HW Config Online; verify that CPU 410-5H status indicates RUN with green LEDs and zero diagnostic faults.
5. In CFC, switch to Test Mode; confirm that live dynamic values update across all charts.

Limitations and Operational Precautions

Never attempt to force an obsolete block into a CPU 410-5H by disabling block consistency checks. CPU 410-5H enforces hardware capacity and execution licensing via the System Expansion Card (SEC). If the program size exceeds the licensed Process Object (PO) count allocated on the SEC, the controller will reject the download with a PO license overrun fault.

Engineer FAQ

Why did the download fail at exactly 6% progress?

At 6%, STEP 7 finishes downloading basic system parameters and begins loading organization blocks and driver system calls (SFCs). Incompatible driver blocks trigger immediate firmware rejection at this threshold.

Can I run CPU 410-5H with PCS 7 V8.0 SP2?

Yes, with the dedicated CPU 410-5H Hardware Support Package (HSP) and the updated PCS 7 Basis Library V8.0 SP2 update installed.

What does 'Generate module drivers' do during compilation?

The CFC compiler inspects HW Config and automatically generates the appropriate diagnostic and signal conditioning blocks (MOD_*, CH_*) matching the hardware.

How do I identify which specific block is rejected by the CPU?

Open the CPU Diagnostic Buffer immediately after the rejection; look for events reporting 'Error loading block [FB/FC/DB Number]' or 'Block cannot be executed in this CPU'.