Siemens PCS 7 ES, OS, AS Software Packages: Functions Compared

1. Overview: How Siemens PCS 7 Splits Engineering, Operator, and Automation Roles

Siemens PCS 7 (Process Control System 7) is structured around three functional station roles that map to three distinct software package families. Understanding the boundary between AS, OS, and ES software is mandatory before a system can be properly licensed, engineered, or maintained. Confusion typically arises because the OS abbreviation carries two valid meanings, and the ES package actually embeds both AS and OS engineering components. This reference isolates the components of each package, lists what an engineer can and cannot do with each license, and provides a configuration and verification path for PCS 7 V6.1 systems.

At the bottom of the hierarchy sits the AS (Automation Station), which is the SIMATIC S7-400 or S7-410 PLC plus the engineering tools that target it. The OS (Operator Station) sits in the middle and provides the WinCC-based supervisory layer. The ES (Engineering Station) sits at the top of the engineering workflow and bundles everything required to author, compile, and download both AS and OS content. The three roles are not strictly bound to three physical PCs; PCS 7 explicitly supports combined ES/OS stations for small plants, while AS content always lives on the PLC itself and is engineered from an ES.

The package model is enforced by the PCS 7 license manager. Installing only the AS package on a PC will not let you open WinCC Explorer; installing only the OS runtime will not let you compile CFC charts. Knowing which physical PC carries which package is therefore the foundation of any PCS 7 network node diagram.

2. AS - Automation Station Software Package

The AS software package is the toolchain that targets the PLC. In PCS 7 V6.1, the AS engineering toolset is essentially STEP 7 V5.4 (with the matching service pack) bundled with the PCS 7 V6.1 add-on libraries. Installing the AS package equips an engineering PC to do everything required to create, modify, compile, and download a PLC program for a SIMATIC S7-400 or S7-410 station.

Components installed by the AS package:

• SIMATIC Manager (STEP 7) - the project tree that holds S7 programs, hardware configuration, and NetPro network views.
• HW Config - the rack/station editor for assembling the AS-400 or AS-410 station (PS, CPU, IM, CP, SM, FM, CP443-1, etc.).
• SCL Compiler - for source-level ST code that generates FBs and FCs.
• CFC (Continuous Function Chart) - the graphical chart editor used for the bulk of PCS 7 application code. Charts are inserted into plant hierarchy folders and run in OB35 (typically 1 s) on the AS.
• SFC (Sequential Function Chart) - for step/transition state machines, used for batch-style and mode-sequenced processes.
• PCS 7 Library V6.1 - the motor block (MOT_SPEED, MOT_SPD), valve block (VALVE_ANA, VALVE_MOT), PID block (CTRL_PID), and dozens of I&C faceplate blocks. The library is what differentiates PCS 7 CFC from a generic STEP 7 install.
• NetPro / S7 Connections - for binding the AS to the OS server across Industrial Ethernet.
• Download / Online tools - online view, watch tables, force tables, diagnostic buffer viewer.

What the AS package explicitly does not do:

• It does not let you open the WinCC Explorer of a PCS 7 OS project.
• It does not let you build OS server or OS client pictures, archives, user administration, or alarm logging.
• It does not include any operator runtime - the AS package is engineering only; the AS station (the PLC) runs the compiled program without any WinCC runtime present.

The AS package is licensed per AS instance. The PCS 7 V6.1 AS engineering license is one of the foundational MLFBs in the bill of materials and is consumed once per engineering seat, not once per PLC. A single ES with one AS package can program any number of AS-400/AS-410 stations in the project, provided the OS-side data point count and S7 connection count license terms are met elsewhere.

3. OS - Operator Station: The Package With Two Meanings

The OS abbreviation is the single largest source of confusion in PCS 7 project documentation because it is used for two completely different concepts. The ambiguity is worth stating explicitly so that subsequent decisions in the configuration step can be checked against it.

OS meaning 1 - the software package family (WinCC for PCS 7): This is the installable software that lives on a PC. Within this meaning, OS splits again into two sub-roles:

• OS Engineering software - the WinCC Explorer and its editors (Graphics Designer, Alarm Logging, Tag Logging, User Administrator, Global Script, Picture Tree Manager, Time Synchronization). Installing OS Engineering is what lets you author pictures, configure archives, and define the operator screens that will run in the plant.
• OS Runtime software - the WinCC Runtime that displays pictures, evaluates alarms, logs tags, and serves the HMI to operators. Runtime alone cannot edit pictures. An OS client traditionally carries runtime only.

OS meaning 2 - the physical role (the Operator Station PC): This is the hardware PC in the plant network. By default, the Operator Station PC runs only OS Runtime (no editing tools). An Operator Station that is also authorized to edit is, in practice, an ES/OS combined station (see Section 6).

What OS Engineering lets you do:

• Open the WinCC project of the OS server, edit .PDL graphics files, add I/O field and faceplate objects, bind tags to AS symbolic addresses.
• Configure Alarm Logging (message classes, colors, acknowledgment rules) and Tag Logging (archive tags, compression, swap-out).
• Configure user administration, time synchronization, and picture hierarchy.
• Compile and download the OS server and OS client projects.

What OS Runtime does not let you do:

• Edit .PDL files. Graphics Designer is not present.
• Edit Alarm Logging or Tag Logging configuration. The user can acknowledge alarms and view trends but cannot add a new archive tag.
• Open SIMATIC Manager or compile CFC charts. The OS package family does not include the AS engineering tools.

OS licensing split: In PCS 7 V6.1, OS Server and OS Client are licensed separately. The OS server license is typically sized by archive tag count and external tag count; the OS client is licensed per installed client. A redundant OS server pair requires a redundancy license add-on. The license key is what enforces the boundary - a runtime-only PC will not pick up the OS engineering editors even if the binaries are physically copied to disk.

4. ES - Engineering Station: The Bundled Toolchain

The ES package is the top of the PCS 7 engineering hierarchy. Installing ES on a PC effectively installs the AS engineering tools and the OS engineering tools, all driven from SIMATIC Manager. The ES is the only seat from which a complete PCS 7 plant can be authored end to end.

Components installed by the ES package:

• Everything in the AS package (SIMATIC Manager, HW Config, SCL, CFC, SFC, PCS 7 Library).
• Everything in the OS Engineering package (WinCC Explorer, Graphics Designer, Alarm Logging, Tag Logging, User Administrator, Global Script).
• The PCS 7 plant view and component view that bridge SIMATIC Manager and WinCC Explorer. The plant view drives both the AS hierarchy and the OS picture hierarchy from a single source of truth.
• NetPro with full S7 connection editing between all AS stations and the OS server.
• Version Trail / version cross-check functions for change management of CFC charts and pictures.

What the ES does not install: ES does not install the OS Runtime. A pure ES is an offline engineering PC; it does not display live plant graphics. To view live plant data, you must install an OS Runtime on the same PC (creating an ES/OS combined station) or have a separate OS Server / OS Client on the network.

Convention: when reading a PCS 7 project document, the term ES almost always refers to the engineering seat (a license, a PC, or both). The ES package can be a single-user license or a floating license served from a license server; the V6.1-era floating option used the standard Siemens License Server (SLS) with parallel ports or USB dongles.

5. Package Capability Matrix

The following table summarizes what each installed package allows and disallows. Use it as a single-page reference when reviewing a project's license allocation.

Decision rule: If the engineer is going to modify the PLC program (FBs, FCs, CFCs, SFCs, HW Config), the seat must include the AS tools. If the engineer is going to modify screens, archives, or alarm routing, the seat must include OS Engineering. A single ES seat covers both activities; two separate engineers on a single ES need to schedule the seat, or each engineer needs their own license.

6. ES/OS Single-Station (Combined) Deployment

PCS 7 explicitly supports a single PC acting as both ES and OS. This is the small-plant / lab / skid configuration where the budget or the rack space does not justify a dedicated engineering PC and a dedicated operator console.

Required software on the combined station:

1. Windows XP Professional SP3 or Windows Server 2003 (the operating systems supported by PCS 7 V6.1 - confirm with the PCS 7 V6.1 Readme for the exact supported list and patches).
2. PCS 7 V6.1 ES package (AS engineering + OS engineering).
3. PCS 7 V6.1 OS Server Runtime (single-station license) or OS Single Station package if you do not need a separate OS client network.
4. SIMATIC NET PC software for the CP1613 / CP1623 / CP1628 communications processor used to talk S7 to the AS.

Typical use cases:

• Lab testing and factory acceptance test (FAT) rigs - one PC, one AS-410 or AS-400 on the bench, scripts and screens edited live.
• Small skid systems with one or two AS stations and one operator panel.
• Training classrooms where students edit CFCs and watch them run on the same PC.

Limitations to flag for the customer:

• The combined station is a single point of failure - if the PC crashes, both engineering and operator view are lost.
• The combined station does not scale to multi-client plants. A separate OS server / client topology is required once more than one operator console is needed.
• PCS 7 V6.1 enforces a maximum number of OS clients per OS server. Verify the limit (typically 32 clients per server in PCS 7, but the licensing tier may restrict it lower) against the SIMATIC HMI catalog for the actual MLFB purchased.

7. Hardware Platform Requirements for Each Role

Each PCS 7 V6.1 role has minimum hardware expectations. These were typical for the V6.1 era; confirm with the official PCS 7 V6.1 Readme file shipped on the installation DVD for the binding requirements.

For combined ES/OS stations, the higher of the ES and OS Server requirements applies. The CP1613 / CP1623 is mandatory for the plant bus because standard Windows TCP/IP cannot guarantee the deterministic timing that PCS 7 expects for AS-OS communication.

8. PCS 7 V6.1 Licensing and MLFB Numbering

Every PCS 7 software component is sold under a Siemens MLFB (Machine-Readable Product Designation). The V6.1-era software MLFBs follow the 6ES7 6xx-xxxxx-xxxx pattern. Exact MLFBs change with service packs, so always quote the MLFB that matches the install DVD in the customer's hand. The catalog structure looks like the table below.

License key mechanics:

• PCS 7 V6.1 uses the Siemens License Server (Automation License Manager in later versions). The license is a file transferred onto a USB dongle, a parallel port dongle, or a license server on the plant network.
• The ES license is consumed only when an engineering tool (SIMATIC Manager, WinCC Explorer) is actually opened. It is released when the tool closes.
• The OS Runtime license is consumed by the running WinCC Runtime service and is not floating - if the OS server reboots and the license is unavailable, the runtime starts in demo mode and watermarks the screens.

9. Add-on Engineering Packages (Drives ES, Route Control, etc.)

The base ES package covers motor blocks, valve blocks, PID, and the standard PCS 7 faceplate library. Specialty equipment requires an additional ES add-on. Each add-on installs as a child package under the parent ES install and registers its own library, its own CFC catalog, and (often) its own faceplates into the WinCC picture tree.

Each add-on has its own MLFB, must be ordered separately, and must be present on the ES and on every OS that displays the add-on's faceplates. A common field issue is that the Drives ES library is loaded on the ES but the SINAMICS faceplates are missing on the OS - the operator sees a placeholder grey box and the alarm log shows "picture not found". The fix is to install the matching OS-side faceplate component shipped with the add-on.

10. Building a Network Node Block Diagram with MLFB Legend

On any PCS 7 project of meaningful size, the network node block diagram (NNBD) should be drawn before hardware is ordered, and the legend on the diagram should list the MLFB of every software and hardware component on every node. The diagram below shows the topology for a mid-sized PCS 7 V6.1 plant.

MLFB legend template (paste into the diagram title block):

| Node      | Hardware MLFB          | Software MLFB (V6.1)        | License type |
|-----------|------------------------|------------------------------|--------------|
| ES-01     | 6ES7 670-... (PC)      | 6ES7 658-... PCS 7 ES        | Single-user  |
| OS-SRV    | 6ES7 670-... (PC)      | 6ES7 658-... OS Server RT    | Server       |
| OS-CL1    | 6ES7 670-... (PC)      | 6ES7 658-... OS Client RT    | Client       |
| OS-CL2    | 6ES7 670-... (PC)      | 6ES7 658-... OS Client RT    | Client       |
| AS-410#1  | 6ES7 410-5H (CPU)      | (AS runtime - no PC SW)      | -            |
| AS-400#2  | 6ES7 417-4H (CPU)      | (AS runtime - no PC SW)      | -            |
| AS-410#3  | 6ES7 410-5H (CPU)      | (AS runtime - no PC SW)      | -            |
| Plant bus | 6GK7 443-1EX20 (CP443) | 6GK1 704-... SIMATIC NET PC  | Per CP       |

The MLFB column is what survives an audit. Without it, you cannot prove that the AS engineering tools on the ES are licensed, that the OS server archive license is sized to the tag count, or that the SINAMICS drives are covered by a Drives ES add-on.

11. Commissioning and Verification Checks

After the ES / OS / AS software is installed and before the first download, run the following checks. They take about 30 minutes and catch 90 percent of the package-related issues seen during site acceptance tests.

1. License visibility. Open the Siemens Automation License Manager on every node. Confirm that every expected license is present and "OK" (not "Missing", not "Demo"). On the ES, the AS engineering and OS engineering licenses must be visible. On the OS server, the OS server runtime license must be visible. On each OS client, the OS client runtime license must be visible.
2. Package presence. On the ES, open SIMATIC Manager and WinCC Explorer from the same Windows session. If WinCC Explorer refuses to open with a license error, the OS Engineering portion of the ES bundle is missing or the license file is corrupt. Re-run the license transfer.
3. Plant view integrity. Open the plant view in SIMATIC Manager. Expand every hierarchy folder. Each AS folder should show its CFC/SFC charts; each OS folder should show its pictures. If a folder is empty after a project download, the OS engineering install on the ES is suspect.
4. Compile and download dry run. Compile the AS program first (full build), then the OS server project, then the OS client projects. A compile failure on the OS side while the AS compile succeeds almost always points to a missing PCS 7 V6.1 library or a WinCC version mismatch.
5. S7 connection check. In NetPro on the ES, right-click each S7 connection between an AS and the OS server and choose "Connection diagnostics". A green status means the connection is online. A red status with error code 0x0001 typically means the CP443-1 on the AS is not online; error 0x0002 typically means a routing issue between subnets.
6. Live picture check. On the OS server, open the runtime. Click into the first process picture. Verify that a motor faceplate shows live feedback (actual speed, current) and that a valve block shows real position feedback. If the picture loads but every I/O field shows "####", the AS-OS connection is up but the symbolic I/O addresses are wrong - the AS engineering data block is missing the relevant bits.
7. Alarm round-trip. Force a single binary input on the AS. The OS server should generate a "process alarm" with the correct timestamp, priority, and message text. Acknowledge the alarm on the OS. The acknowledgment should propagate back to the AS and clear the "unacknowledged" bit in the CFC chart.

If every step above is green, the package allocation is correct and the project is ready for operator handover.

12. Field-Proven Pitfalls and Migration Notes

The following issues are repeatedly observed on PCS 7 V6.1 site work and are worth pre-empting in any project plan.

Pitfall 1 - The AS package cannot edit WinCC pictures. This is the single most common question from engineers new to PCS 7. The AS package installs CFC, SFC, and HW Config, but it does not install the WinCC Explorer or Graphics Designer. To change a single button color on an operator screen, the seat must include OS Engineering - either as a standalone OS Engineering package or as part of the ES bundle.

Pitfall 2 - OS Runtime cannot be used to edit. An operator station that carries only the OS Runtime license will open the plant pictures, but double-clicking a faceplate will not let the operator drop into CFC editing. The right-click "Open CFC" option requires AS engineering tools on the same PC, which means an ES or an ES/OS combined station. Do not promise operators "online CFC tuning" on a runtime-only client.

Pitfall 3 - Mixing PCS 7 V6.1 with newer WinCC versions. The PCS 7 V6.1 OS Engineering binaries are tied to a specific WinCC version (typically WinCC V6.2 SP3 in the V6.1 era). Installing a newer WinCC on the same PC will break the OS Engineering compile. Always install PCS 7 V6.1 from its own DVD and do not layer an unrelated WinCC V7 install on top of it.

Pitfall 4 - Licensing the OS server by external tag count. The OS server runtime license is tiered. Under-sizing the license results in the runtime starting in demo mode and watermarking the screens; over-sizing is wasted budget. The number to count is external tags - that is, every address the OS reads from the AS via the S7 connection. Internal derived tags (calculations, status flags) do not count.

Pitfall 5 - The AS engineering license does not cover the OS side. When the same engineer is doing both PLC and screen work, give them a single ES seat - do not buy an AS package plus an OS Engineering package separately. The ES bundle is cheaper than the two halves purchased individually.

Pitfall 6 - Mixing AS-400 and AS-410 in the same project. PCS 7 V6.1 supports both, but the CFC library and the OB35 / OB1 cycle differ subtly. The AS-410 supports the new CPU 410-5H redundancy concept, while the AS-400 with CPU 417-4H uses the older S7-400H redundancy. CFC charts compile and run on both, but if the project includes S7 F Systems safety code, the F-runtime license is sized per AS family.

Migration note. Customers upgrading from PCS 7 V6.1 to a newer PCS 7 version (V7.x, V8.x, V9.x) typically have to replace the OS Engineering tools with the new release's OS Engineering, replace the AS engineering with the new STEP 7 / CFC, and relicense everything. The AS PLC program (CFC / SFC) is largely source-compatible, but a project migration tool is run in SIMATIC Manager to upgrade the project format. Plan at least a week of engineering effort per AS station for the migration, plus a full re-loop check on the OS side.

Related Documentation

For the official description of the package roles, the PCS 7 V6.1 manual set shipped on the install DVD is the binding reference. The PCS 7 Process Control System - Engineering System manual and the PCS 7 Operator Station manual cover ES and OS roles in detail. The PCS 7 V6.1 Readme lists the supported Windows versions, the supported service packs, and the known installation issues. For the current product family, the Siemens Industry Online Support portal is the authoritative source of KB articles, firmware updates, and migration guides.

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