How to Upgrade SIMATIC S7-410 System Expansion Card (SEC) Process Objects and Resolve Download License Errors

When downloading a PCS 7 program to a SIMATIC CPU 410-5H (MLFB 6ES7410-5HX08-0AB0) and encountering errors such as 'Maximum number of communication jobs exceeded' or AS RT PO license shortages, the project has exceeded the Process Object capacity authorized by the CPU's System Expansion Card (SEC). Unlike classic S7-400 controllers that rely purely on RAM/Flash cards, the CPU 410 hardware performance is governed by the hardware SEC card. To resolve this, purchase the required CPU 410 Expansion Pack licenses (in 100 or 500 PO increments), connect to the CPU online in Automation License Manager, and execute the online SEC upgrade directly in RUN mode.

Architecture of the CPU 410-5H System Expansion Card (SEC)

The SIMATIC CPU 410-5H (order number 6ES7410-5HX08-0AB0) represents the standard high-performance automation controller for modern PCS 7 architectures.

Unlike legacy S7-400 CPUs (such as CPU 416 or CPU 417) which were differentiated by distinct physical hardware models with fixed memory limits, all CPU 410-5H units share identical, high-grade hardware processing power:
* The operational capacity and maximum Process Object (PO) limit of the controller are determined exclusively by the System Expansion Card (SEC) inserted into the rear compartment of the CPU.
* SEC cards are pre-configured from the factory with baseline capacities (such as 100 POs, 500 POs, or 1000 POs).
* When a compiled CFC program instantiates more technological blocks than authorized by the SEC, the controller blocks program downloads or flags license violation alarms in the diagnostic buffer.

Distinguishing AS RT POs, OS RT POs, and SEC Hardware Capacity

To maintain commercial licensing compliance, automation engineers must clearly distinguish three separate licensing concepts:
1. CPU 410 SEC Hardware Capacity:
* A hardware-locked capacity entitlement stored cryptographically on the physical SEC memory card.
* Authorizes the CPU 410 operating system to execute a specific number of Process Objects in its real-time program image.
2. AS RT Process Objects (Software License):
* A runtime software license managed in Automation License Manager on the Engineering Station to license software block compilation.
3. OS RT Process Objects (WinCC License):
* Authorizes the WinCC OS Server to monitor and control technological process tags.
* Redundant OS servers require symmetric licensing across both physical server nodes.

Calculating Process Object (PO) Consumption in SIMATIC Manager

Before initiating an SEC upgrade, determine the exact PO count required by the project:

Open Process Object View:
* In SIMATIC Manager, open the multi-project.
* Select the target AS station and open View > Process Object View.
Inspect Chart PO Totals:
* In the bottom status bar, SIMATIC Manager displays: Configured POs: X, Licensed POs: Y.
* A Process Object corresponds to an instantiated technological block with operator control and monitoring attributes (such as MotL, VlvL, PIDConL, DoseL). Basic math and logic blocks (e.g., And04, Add04) do not consume POs.
Determine Required Upgrade Size:
* If the project requires 350 POs and the SEC currently has 100 POs, you must order an expansion volume of 300 POs (purchased as three 100 PO packs) to reach a total capacity of 400 POs.

Step-by-Step Online SEC Upgrade Procedure via Automation License Manager

One of the greatest operational advantages of the CPU 410-5H is that its SEC capacity can be upgraded online in RUN mode without shutting down the plant:

Procure Expansion Packs:
* Order the required CPU 410 Expansion Pack licenses (e.g., 100 PO pack 6ES7653-2CA00-0XE0 or 500 PO pack 6ES7653-2CD00-0XE0) through an authorized Siemens distributor.
* Transfer the delivered license keys into Automation License Manager (ALM) on the Engineering Station.
Connect ALM to Target CPU 410:
* In ALM, select menu Edit > Connect Target System > Connect AS410.
* In the dialog box, select the CPU 410 automation station from the accessible nodes list or enter its plant bus IP address.
* The CPU 410 appears in the ALM navigation tree under Target Systems.
Transfer License Keys to CPU:
* Drag the CPU 410 Expansion Pack license keys from drive C: and drop them onto the connected AS410 target system node.
Execute License Upgrade:
* In the online view of the CPU 410 in ALM, select the newly transferred license key.
* Select menu License Key > Upgrade....
* ALM communicates with the CPU operating system, cryptographically writes the new PO capacity directly to the SEC, and updates the hardware authorization table.
* The CPU continues executing active process control in RUN mode throughout the procedure.

Comparison of S7-400 Memory Cards vs CPU 410 SEC Architecture

The table below compares the hardware capacity architectures of classic S7-400 controllers versus the CPU 410-5H.

Architecture CharacteristicClassic S7-400 (CPU 416 / 417)SIMATIC CPU 410-5HHardware Capacity ModelFixed CPU model with static RAM/ROMSingle hardware unit (6ES7410-5HX08-0AB0) scalable via SECMemory Card FunctionStandard RAM / Flash MMC memory storageProprietary System Expansion Card (SEC) with cryptographic POsCapacity Upgrade MechanismReplace physical CPU with larger modelOnline PO upgrade in RUN via ALMPO Expansion GranularityStep changes by CPU modelFlexible 100 PO or 500 PO expansion packsPlant Downtime for UpgradePlanned shutdown required to swap CPUZero downtime (Bumpless upgrade in RUN)

Verification

To confirm that the SEC PO upgrade was successful:
1. In Automation License Manager, select the connected AS410 station: confirm that the total licensed PO capacity matches the new target.
2. In SIMATIC Manager, open PLC > Module Information for the CPU 410. Select the Special Statistics or Performance tab: verify that the authorized PO limit reflects the upgrade.
3. In CFC, initiate a program download: PLC > Download > Changes Only.
4. Confirm that the download dialog accepts the program without license warnings and that the CPU remains in RUN mode.

Limitations and Operational Precautions

In redundant S7-400H / CPU 410-5H systems, SEC PO capacity must be expanded symmetrically on both CPU SEC cards; asymmetric licensing prevents redundant master-standby synchronization.
Never remove the physical SEC card from the rear of the CPU while power is applied or while the CPU is in RUN mode; removing the card triggers an immediate CPU STOP.
When planning system expansions or purchasing replacement equipment, always validate final license quantities and MLFBs against the applicable Siemens catalog and authorized distributor quotation.
SEC expansion packs cannot be divided or split across multiple controllers; an ordered pack must be assigned to a single SEC card.

Engineer FAQ

Can an SEC card be transferred to a spare CPU 410?

Yes. The PO capacity entitlement is stored directly on the physical SEC card. If a CPU 410 unit suffers a hardware failure, you can remove the SEC card from the damaged CPU and insert it into a replacement CPU 410, transferring the full licensed capacity instantly.

Why did the CPU 410 report 'Maximum number of communication jobs exceeded'?

This warning typically accompanies an attempt to download a CFC project whose Process Object count exceeds the licensed SEC limit, or when communication instance handles (such as S7 Named Connections) exceed the allocated memory quota in CPU properties.

What is the maximum PO capacity supported by a single CPU 410-5H?

A standard CPU 410-5H can be expanded up to 2600 Process Objects (or up to its maximum memory boundary), providing massive processing headroom for large chemical and refining units.