Configuring Compact Industrial Architectures: SIMATIC PCS 7 BOX RTX vs Standard Modular Systems

SIMATIC PCS 7 BOX RTX integrates a software controller (WinAC RTX) and a WinCC Single Station (OS) onto a single rugged industrial PC (such as the SIMATIC IPC627C). When deploying a PCS 7 BOX RTX with an external Engineering Station (ES), the minimum procurement scope comprises the IPC hardware with real-time communications hardware, the PCS 7 BOX RTX Software package (incorporating WinAC RTX, OS Single Station, and runtime Process Object licenses), and the external ES engineering license. Because the controller runs in software on the PC, standard S7-400H hardware redundancy and large-scale multi-client server topologies are not supported.

Architecture of PC-Based Control: SIMATIC PCS 7 BOX RTX

In small automation plants, compact package units, and OEM skid systems, deploying a full-scale modular DCS architecture (with separate S7-400 hardware racks, dedicated redundant OS servers, and engineering stations) is often economically or physically impractical.

To address this market segment, Siemens developed the SIMATIC PCS 7 BOX family:
* The All-In-One Philosophy: Combines the Automation Station (AS) and Operator Station (OS) inside a single compact Industrial PC (IPC).
* The WinAC RTX Engine: The automation controller executes not on a proprietary hardware CPU backplane, but as an embedded real-time software controller: SIMATIC WinAC RTX. Operating underneath a Windows real-time extension (IntervalZero RTX), WinAC executes deterministic logic cycles (OB1, cyclic OB35 down to 1 ms) isolated from Windows operating system crashes or reboots.
* Integrated WinCC Single Station: The WinCC runtime subsystem runs on the same IPC, communicating with WinAC RTX via internal high-speed shared memory (Softbus / PC Internal), completely eliminating network transmission bottlenecks between AS and OS.

Hardware Foundation: SIMATIC IPC627C and Fieldbus Interfaces

The physical deployment of a PCS 7 BOX RTX centers on high-reliability industrial hardware, such as the SIMATIC IPC627C (6AT8010-6BA00-0BA0):

Industrial PC Characteristics: Compact metal enclosure, solid-state drives (SSD) or RAID 1 hard drives, ECC RAM, and high thermal tolerance for harsh factory environments.
Fieldbus and I/O Connectivity:
Because there is no S7-400 rack backplane, all distributed I/O (such as ET 200M, ET 200S, or ET 200SP) must connect via industrial fieldbuses:
PROFIBUS DP: Supported via an integrated CP 5611 / CP 5622 communications processor or PCI slot card.
PROFINET IO: Supported via dedicated industrial Ethernet interfaces (such as CP 1616 onboard or standard server NICs using Softnet-PN).
Plant Bus Interface: A secondary standard Ethernet port connects the IPC to the external Engineering Station (ES) for programming downloads and diagnostic monitoring.

Software Licensing Scope: BOX RTX Runtime vs External ES Licensing

Configuring a viable PCS 7 BOX RTX system requires two distinct software packages:

PCS 7 BOX RTX Software Package (6ES7650-1CL00-2XB5):
Installed directly on the IPC627C. This bundle provides:
* WinAC RTX Software Controller: Embedded real-time execution engine.
* WinCC Single Station Runtime: Full SCADA operator interface for local displays.
* Runtime Process Objects (PO): Tiered licenses (typically 250, 500, or 2,000 POs) covering both AS runtime execution and OS visualization.
* SIMATIC NET PC Software: Drivers and Station Configuration Editor.
External Engineering Station (ES) Software (6ES7658-2CX58-0YB5):
Runs on a separate desktop or engineering laptop. Includes SIMATIC Manager, CFC, SFC, and WinCC Engineering tools. The external ES compiles the project and downloads the AS program to WinAC RTX and the OS project to the WinCC Single Station over Industrial Ethernet.

Process Object Capacity and Architectural Boundaries

While PCS 7 BOX RTX delivers complete DCS capabilities in a compact footprint, it is subject to strict architectural boundaries:

Capacity Limits: Engineered for applications up to a maximum of 2,000 Process Objects (typically 250 to 1,000 POs). Deploying larger projects exceeds the IPC's memory caching and real-time execution bandwidth.
No S7-400H Hardware Redundancy: WinAC RTX cannot form a fault-tolerant redundant controller pair. Redundant CPU failover with zero bumpless switchover (as provided by S7-400H or CPU 410-5H) is strictly unavailable.
Limited Client-Server Topologies: The integrated OS operates primarily as a Single Station. While it can host up to two Web Navigator clients or thin clients, it cannot serve as a central OS Server for multi-client control room environments.

Comparison: PCS 7 BOX RTX vs Microbox RTX vs Modular S7-400 / AS 410

The following table contrasts PCS 7 BOX architectures against standard modular systems:

Architectural MetricSIMATIC PCS 7 BOX RTX (IPC627)SIMATIC PCS 7 Microbox (IPC427)Standard Modular AS 410 / S7-400Form FactorCompact Box IPC with PCI slotsUltra-compact fanless DIN-rail IPCModular 19" Rack / DIN RailController TypeSoftware Controller (WinAC RTX)Software Controller (WinAC RTX)Hardware CPU (CPU 410-5H / S7-417)Maximum PO CapacityUp to 2,000 POsUp to 500 POsUp to 2,600+ POs per CPUHardware RedundancyNot supportedNot supportedFully supported (S7-400H / FH)Fail-Safe (F-Systems)Supported via S7 F Systems RTXSupported via S7 F Systems RTXFully supported (SIL 3 / Ple)Integrated HMIYes (WinCC Single Station)Yes (WinCC Single Station)No (requires separate OS server)Typical Target ApplicationLarge OEM skids, pilot plantsSmall standalone utility packagesFull-scale refinery / chemical plantPrimary MLFB Reference6ES7650-1CL00-2XB56ES7650-1BD18-0YA06ES7410-5HX08-0AB0

Step-by-Step Procedure to Commission a PCS 7 BOX RTX System

Follow this verified engineering workflow to commission a PCS 7 BOX RTX system:

Verify IPC Hardware and BIOS Settings:
* Inspect the IPC627C. Ensure the real-time extension (RTX) is supported in BIOS.
* Enable Intel VT-x and disable power-saving CPU C-states to prevent real-time clock jitter.
Configure Station Configuration Editor on IPC:
* Open Station Configuration Editor on the IPC627C.
* Add the components into virtual rack slots matching standard PCS 7 Box conventions:
- Slot 1: WinCC Application
- Slot 2: WinAC RTX
- Slot 3: IE General (for external ES plant bus)
- Slot 4: CP 5622 / CP 5611 (for PROFIBUS DP) or CP 1616 (for PROFINET IO)
Configure the PC Station in SIMATIC Manager (on ES):
* On the external ES, create a new SIMATIC PC Station matching the exact station name of the IPC.
* In HW Config, insert the matching virtual rack components in Slots 1 through 4.
* Add distributed I/O (e.g., ET 200SP) to the WinAC RTX fieldbus master line.
Compile and Download:
* In NetPro, configure the S7 connection between WinCC Appl. and WinAC RTX using internal connection routing (Named Connections via PC Internal).
* Download the hardware configuration to the IPC over Industrial Ethernet.
* Download the CFC/SFC program to WinAC RTX.
* Compile and download the OS project to the WinCC Single Station.

Verification

Verify operational readiness of the compact system:
1. On the IPC627C, open the WinAC RTX Control Panel; verify that the software controller state displays RUN with green indicator and zero bus faults.
2. Open WinCC Explorer on the IPC and activate Runtime; confirm that the process graphics display live fieldbus measurements from connected distributed I/O without communication delay.
3. Open Windows Task Manager on the IPC; verify that CPU utilization remains stable (< 40%) and that real-time threads run without preemption.
4. From the external ES, execute a minor CFC delta change; confirm that delta compile and delta download execute cleanly in RUN mode.

Limitations and Operational Precautions

Windows Reboots Affect OS but Not RTX: While WinAC RTX is shielded from many Windows user-mode application faults, a full Windows operating system reboot or bluescreen (BSOD) will eventually reset the hardware and stop WinAC. Maintain strict cyber hygiene and disable automated Windows updates on the IPC.
Separation of Network Interfaces: Never mix the fieldbus I/O network with the external plant bus network on the same physical Ethernet NIC. Use dedicated physical adapters for PROFINET IO and plant bus communications.
Uninterruptible Power Supply (UPS): Industrial PCs are susceptible to file system corruption if power drops abruptly during write operations. Always power the IPC627C through an industrial UPS with automated shutdown signaling.
Commercial Accuracy: Verify the IPC hardware MLFB (6AT8010-6BA00-0BA0 / IPC627C), runtime software bundle (6ES7650-1CL00-2XB5), and engineering licenses against current Siemens product catalogs. Procure through an authorized Siemens distributor quotation.

Engineer FAQ

Can an external Engineering Station be eliminated by engineering directly on the PCS 7 BOX RTX?

While Siemens offers a 'PCS 7 BOX RTX Engineering' bundle that installs STEP 7 and CFC directly on the IPC, running intensive engineering compilations on the same machine running active process control and operator graphics is strongly discouraged in production environments.

What happens to the WinAC RTX controller if WinCC Explorer crashes?

Because WinAC RTX executes in a protected real-time kernel extension (RTX) operating below the Windows OS layer, a crash or restart of the WinCC user interface will not stop the controller. Process control continues uninterrupted.

Can a PCS 7 BOX RTX be upgraded to an S7-400H redundant system later?

The software controller itself cannot become an S7-400H. However, the engineering project (CFC charts, SFC sequences, and WinCC screens) can be migrated to an S7-400H or CPU 410-5H hardware station with minimal refactoring.

Does PCS 7 BOX RTX support safety-instrumented functions (S7 F Systems)?

Yes. Siemens offers S7 F Systems RTX, allowing the software controller to execute fail-safe logic (SIL 3 / Ple) over PROFIBUS / PROFINET with PROFIsafe distributed I/O.