S7-Graph on a PCS 7 Engineering Station: Compatibility, Installation, and Field-Proven Topologies

Siemens S7-Graph and the SFC editor used inside PCS 7 share the same Simatic Manager shell, but they belong to two distinct, version-coupled product lines. Installing S7-Graph (a STEP 7 optional package) on a workstation that already hosts PCS 7 is officially treated as an unsupported configuration, even though isolated field reports describe successful side-by-side installs. This reference covers the architectural reasons for that restriction, the actual version coupling, the documented and undocumented installation paths, the recommended engineering station topologies (physical, dual-boot, virtualized), and the migration routes that keep a mixed S7-300 / CPU-410 fleet maintainable.

1. Problem Definition: Two Product Lines, One Shell

STEP 7 (the engineering tool for SIMATIC S7-300 / S7-400 / WinAC) and PCS 7 (the process control system engineering tool, built on top of STEP 7) both load into the same Simatic Manager IDE. From a UI perspective they look almost identical, which is the source of most coexistence mistakes. Underneath, however, they install different sets of:

• Version-coupled optional packages (S7-Graph, S7-PLCSIM, S7-SCL, S7-HiGraph, CFC, SFC, …)
• Hardware catalogs and device library versions
• Authorized SIMATIC objects in the project tree (CFC charts, SFC charts, S7-Graph FB blocks)
• Compiler/linker versions and the internal S7-strip generation rules

PCS 7 always ships its own internal STEP 7 baseline, and any attempt to install a STEP 7 optional package against that baseline must satisfy the package's own STEP 7 prerequisite. When the prerequisite and the embedded STEP 7 version disagree, the optional package installer either refuses, registers a hotfix that PCS 7 later overwrites, or silently writes into a PCS 7-protected directory tree.

2. The Official Siemens Position

Siemens' general position, repeated across PCS 7 release notes, the PCS 7 Installation Manual, and the SIMATIC Compatibility Tool, is that a single engineering station may host either STEP 7 with its optional packages or PCS 7 with CFC/SFC, but not a hand-mixed combination. The SIMATIC Compatibility Tool (Siemens Compatibility Tool) is the only sanctioned lookup that resolves which STEP 7 version is embedded in a given PCS 7 version, and it is used to verify whether a third-party optional package can sit on top.

For S7-Graph specifically, the result is the same as for S7-HiGraph, S7-PDIAG, S7-Fuzzy, and the S7 PID Self-Tuner: the tool greys S7-Graph out when the base tool is selected as "PCS 7 Vx.y". Selecting "STEP 7 V5.x" exposes S7-Graph as a selectable option. This grey-out is the public, contractual answer to the question "can I install S7-Graph where SFC (PCS 7) is installed?" — and the answer it encodes is no for any Siemens-supported configuration.

3. S7-Graph vs. PCS 7 SFC vs. CFC

Engineers often ask why Siemens ships two sequential editors. The reason is product scope, not redundancy.

For new PCS 7 work, the rule is to use SFC and CFC only. For legacy S7-300 stations that were never migrated into PCS 7, S7-Graph is still the editor of choice, and that is exactly the scenario that creates the coexistence question.

4. Version Coupling: The Hidden Constraint

Every release of S7-Graph is published as a hotfix set against one specific STEP 7 minor version. PCS 7 V8.1 embeds STEP 7 V5.5; PCS 7 V8.2 embeds STEP 7 V5.5 + SPx; PCS 7 V9.0 embeds STEP 7 V5.6. The graph below shows how a single PCS 7 service pack move cascades through the dependent optional packages.

The coupling is one-directional: a newer S7-Graph hotfix will not necessarily run on an older STEP 7, and a newer STEP 7 will not register an older S7-Graph. PCS 7 service packs are not guaranteed to leave the S7-Graph registration intact, so even an install that worked yesterday can break after a routine PCS 7 update.

5. Documented Install Cases from the Field

The most often quoted side-by-side configuration in user discussions is:

• Host OS: Windows (engineering station class, e.g. Win 7 / Win 10 LTSC depending on PCS 7 release)
• PCS 7: V8.1 (and later service packs)
• Embedded STEP 7: V5.5 (installed by the PCS 7 setup)
• S7-Graph: V5.3 SP7, installed afterwards on top of the embedded STEP 7
• Reported result: S7-Graph launches, can open and edit .GR7 source files, and download to the S7-300 CPU on the secondary network

Several caveats apply to that report:

1. It is a field-verified observation, not a Siemens-supported combination. No call to Siemens Technical Support will be accepted against this layout.
2. It only works because the S7-Graph V5.3 line is built against STEP 7 V5.5, which is the exact baseline embedded in PCS 7 V8.1. A change to PCS 7 V8.2 (which can move the embedded STEP 7 baseline) typically invalidates the install.
3. Hotfixes for either side that arrive after the install are likely to break it without warning.

6. Engineering Station Topologies

For a fleet that contains both PCS 7 automation systems (CPU-410 / AS 400) and STEP 7-only S7-300 stations with S7-Graph sequences, three engineering station topologies are field-proven.

6.1 Dedicated PCS 7 ES + Dedicated STEP 7 ES (recommended)

Two physical PCs, one per product line. This is the layout Siemens prescribes and the one that survives all support cases, all service packs, and all license audits. The STEP 7 PC carries S7-Graph, S7-SCL, PLCSIM, and any machine-level optional package. The PCS 7 PC carries CFC, SFC, the PCS 7 OS engineering tools, and the PCS 7 authorization.

6.2 Dual-Boot ES (single hardware, two partitions)

One workstation, two partitions, two OS images. Each partition boots a clean product line: one boots into the PCS 7 environment, the other boots into the STEP 7 environment. The advantage is hardware consolidation; the drawback is that only one product line is online at a time, so you cannot modify a CPU-410 and an S7-300 simultaneously during a hot cutover.

Boot the partition you need, never both. This is the only way to avoid the version-cascade conflict entirely while sharing a single hardware investment.

6.3 Virtualized ES (VMware / Hyper-V)

Run the PCS 7 ES on the host and the STEP 7 ES inside a virtual machine (or vice versa). Virtualization introduces its own concerns: USB license dongles must be passed through to the guest, the network bridging for the plant bus must use a dedicated NIC in promiscuous mode, and the time-sync source for PCS 7 OS must be the host clock or a dedicated NTP source rather than the virtualized clock.

Recommended VMware configuration for STEP 7 in a VM:

• VMware Workstation Pro or ESXi with hardware version compatible with the chosen Windows guest
• One physical NIC bridged to the STEP 7 network (MPI/Profibus/Profinet)
• USB controller with the S7-Graph license dongle mapped to the guest
• CPU and memory sizing to match STEP 7 / S7-Graph recommended hardware list
• Snapshot taken before any S7-Graph hotfix so a failed upgrade can be rolled back in seconds

7. Verification Procedure for a Side-by-Side Install

Where the engineering decision is to accept the unsupported route, use the following verification sequence to confirm that the install is actually functional, not just registered. This procedure must be re-run after every PCS 7 service pack.

1. Open Simatic Manager. Confirm that the project tree shows both the CFC/SFC chart folder types and the S7-Graph source file types (\*.GR7) opening in their respective editors.
2. Open one existing GR7 source file from the S7-300 station. Confirm the graph opens, can be edited, and re-saves without warning.
3. Compile the GR7 file. Check that the resulting FB and instance DB download to the S7-300 CPU without SF LED and without block-consistency errors in the diagnostic buffer.
4. Open one existing CFC chart from the PCS 7 station. Confirm the chart compiles, the CPU-410 downloads successfully, and the OS faceplates continue to bind.
5. Force a cross-check by attempting a PCS 7 Charts → Compile pass on a multiproject that contains both the CPU-410 AS and the S7-300 AS. The pass must complete without "optional package missing" errors.
6. Apply a deliberately minor change to the GR7 file and re-download. Confirm the S7-300 stays in RUN and no STOP is forced by the S7-Graph runtime.
7. Capture a full screenshot set and a Service Desk-signed change record before any production download.

8. Migration Routes That Avoid the Conflict Entirely

If a long-term fix is acceptable, the conflict can be eliminated by removing one of the two product lines from the workstation.

8.1 Migrate the S7-300 program into PCS 7

Open the STEP 7 project in a dedicated STEP 7 ES, convert the S7-Graph FB to an equivalent SFC + CFC representation, then import the result into the PCS 7 multiproject under a new AS 300 station. The migration is a one-time engineering effort and removes the need for S7-Graph on the ES. The SFC editor inside PCS 7 supports the same state machine semantics and adds native operator prompts on the OS.

8.2 Expose the S7-300 as a distributed I/O station of the PCS 7 AS

Keep the S7-300 hardware in the field, but stop maintaining its program on the PCS 7 ES. Connect the S7-300 to the PCS 7 AS via an IM (Interface Module) over Profibus or Profinet, and address its I/O as standard distributed I/O. PCS 7 then sees the S7-300 only as a DP station or PN device, and the S7-Graph sequence stays on a dedicated STEP 7 ES that is no longer in the same physical workstation as the PCS 7 tooling.

The PCS 7 ES no longer needs S7-Graph. The STEP 7 ES no longer needs PCS 7. Each product line lives in its native environment, support is unrestricted, and the only constraint is the IM mapping table, which is engineering-controlled.

9. Pre-Install Decision Flowchart

10. Risk and Support Matrix

11. Commissioning Checklist for a Mixed Fleet

1. Inventory every CPU type in the fleet: CPU-410 / AS 410 / AS 400 / AS 300 vs. standalone S7-300 / S7-400 with S7-Graph sequences.
2. Decide which engineering stations are STEP 7, which are PCS 7, and which are dual-purpose.
3. For every dual-purpose or virtualized ES, document the Simatic Manager version, the optional package versions, and the license keys in a controlled spreadsheet.
4. For every S7-Graph file, capture the S7-Graph version that last edited it. The .GR7 file header records the editor version; mismatches will be refused by the runtime.
5. For every PCS 7 service pack upgrade, schedule a re-verification pass on every dual-purpose ES (see Section 7).
6. For every change to a S7-Graph sequence on a station that is also a PCS 7 I/O station, follow the standard PCS 7 change-management workflow and re-test OS faceplate bindings.
7. For virtualization, keep the host NTP source authoritative and do not let the guest's virtualized clock drift into the plant bus time domain.
8. Reserve at least one offline workstation as a "golden image" with the exact PCS 7 / STEP 7 / S7-Graph combination that was used for the last successful FAT.

12. Summary of the Compatibility Answer

The answer to "can I install S7-Graph on a PC where SFC (PCS 7) is installed?" is unambiguous in the official Siemens tool: no, not in a supported configuration. The reason is not the existence of overlapping editors but the version-cascade rule: PCS 7 owns its embedded STEP 7 baseline, and every STEP 7 optional package is locked to a specific STEP 7 minor version. The only sustainable answers for a long-lived installation are a separate engineering station, a dual-boot partition, or a virtualized guest. A field-reported side-by-side install of S7-Graph V5.3 SP7 on PCS 7 V8.1 is possible because both products sit on the same STEP 7 V5.5 baseline, but it is non-supported, fragile across service packs, and disqualifies the workstation from any Siemens support case.