Problem Overview
Engineers commissioning a Siemens PCS 7 V7.1 SP3 system occasionally need to install the engineering station (ES) and operator station (OS) on a temporary PC while a project-specific workstation is on order. The challenge arises when the only available machine is a legacy desktop that does not meet the disk-capacity figures published in the official readme file. A typical scenario: an Intel Pentium 4 class machine with 2 GB RAM, an 80 GB hard disk, and a 20 GB C: partition, where the readme states that 120 GB of free disk space is recommended.
This article documents a field-verified method to install PCS 7 V7.1 SP3 on such a legacy PC, the performance caveats that come with the choice, and the migration procedure required to move the license and runtime data to the replacement PC when it arrives.
Affected Versions and Components
- Process Control System: SIMATIC PCS 7 V7.1 SP3 (released as a service pack for the V7.1 line)
- Hardware platform: Intel Pentium 4 processor, 2 GB system RAM, 80 GB HDD, 20 GB C: partition
- Component scopes evaluated: ES (Engineering Station), OS (Operator Station); no Batch, Route Control, or SIMATIC PDM components installed during the temporary build
- Target workflow: pre-commissioning only – final commissioning is performed on the replacement PC
Minimum Hardware Requirements for PCS 7 V7.1 SP3
The readme file shipped with PCS 7 V7.1 SP3 lists the recommended minimum hardware configuration. For the Engineering Station / Operator Station single-user case the relevant figures are:
| Component | Minimum (per readme) | Legacy PC in Question | Status |
|---|---|---|---|
| Processor | Intel Pentium 4, ≥ 2.4 GHz (CAS) – newer CPUs for higher releases | Intel Pentium 4 | Meets minimum |
| System RAM | 2 GB (ES), 2 GB (OS single-user) | 2 GB | Meets minimum |
| Free hard disk space | 120 GB recommended (full install footprint) | 80 GB total, 20 GB on C: | Below recommended |
| Operating system | Windows XP Professional SP2/SP3 (32-bit) or Windows Server 2003 for ES | Per local readme | Verify per local readme |
The 120 GB figure in the readme represents the full installation footprint, including all optional components (Batch, Route Control, PDM, S7-PLCSIM, SFC Visualization, SFC Documentation, examples, Help system, and SQL Server/MSDE databases for archive/log configuration). Field practice shows that a basic engineering install with no Batch, no Route Control, and no PDM consumes only about 19 GB of disk space.
Root Cause Analysis of the Disk-Size Mismatch
The mismatch is a planning artefact, not a binary compatibility issue. The installer of PCS 7 V7.1 SP3 does not check for a minimum disk size above a small lower bound; it only checks whether the target partition has enough free space for the components selected in the setup dialog. Three drivers cause the published 120 GB recommendation:
- Archive sizing: WinCC alarm and tag logging databases grow at runtime. A 30-day retention window for a mid-sized project will commonly require 20-50 GB on the archive drive alone.
- Optional components: SIMATIC PDM (Process Device Manager), Route Control, SFC Visualization, and BATCH flexible expansion each add 2-15 GB of additional footprint.
- SQL Server / MSDE growth: The embedded database engine allocates transaction log space that expands during engineering.
On a temporary build intended for pre-commissioning only, none of these drivers apply. The 20 GB C: partition and 80 GB total drive are therefore sufficient for the short term, with a clear caveat that archive retention must be tuned aggressively or stored externally.
Solution: Partition Strategy and Install Workflow
Step 1 – Repartition the Legacy Disk
- Back up any data currently on the disk – repartitioning is destructive on a disk that already contains an operating system partition.
- Boot the legacy PC from a Windows PE or commercial partition manager (e.g. GParted, EaseUS, or Acronis Disk Director).
- Resize the C: partition upward. Field-recommended size for a temporary PCS 7 install: 30 GB for C: (operating system + PCS 7 base install) plus the remainder as a data partition D: used for WinCC projects, archives, and swap.
- Apply the changes and reboot. Reinstall or repair the Windows XP / Windows Server 2003 image so the boot record and MBR are aligned to the new partition layout.
Step 2 – Pre-Install Verification
- Confirm Windows is fully patched to the SP level documented in the local readme (Windows XP SP2/SP3 is typical for V7.1).
- Disable antivirus real-time scanning during the install – Siemens setup performs thousands of file copies and antivirus software can double the install time.
- Verify the following Windows components are present and enabled:
- Message Queuing (MSMQ)
- Internet Information Services (IIS) if WinCC Web Navigator will be used
- DCOM and COM+ services set to Automatic
- Set the screen resolution to 1024 x 768 minimum – PCS 7 OS Runtime requires 1024 x 768 as a floor and behaves erratically on smaller displays.
Step 3 – Install PCS 7 V7.1 SP3
- Insert the PCS 7 V7.1 SP3 DVD or mount the ISO.
- Start the setup as a local administrator account.
- When prompted for the install type, choose ES (Engineering Station) or OS (Operator Station) Single-User as required. For a single physical machine used for both engineering and operator visualization, use the ES/OS Single-User package.
- Deselect optional components that are not required for pre-commissioning:
- SIMATIC BATCH
- Route Control
- SIMATIC PDM (only enable if the project uses intelligent field devices such as HART or PROFIBUS-PA)
- Examples and Demo Projects (can consume 1-2 GB)
- Select the target drive: install the PCS 7 base to C:\, place WinCC projects and archives on D:\.
- Restart when prompted. The post-install reboot is mandatory – setup writes registry keys and DCOM configurations that are only finalized during the first boot.
Step 4 – License the Installation
- Install the Automation License Manager (ALM) – bundled on the DVD.
- Transfer the license from the USB License Key (Dongle) or from the license file. With a USB dongle, the license is auto-detected; with a software license, use ALM → License Key → Transfer to push the license to the local PC.
- Verify with ALM → License Analysis that all required modules (AS Engineering, OS Runtime, WinCC, optional components) show valid status.
License Migration to the Replacement PC
When the project-specific Dell T1600 (or equivalent) workstation arrives, the license must move from the temporary PC to the new one. PCS 7 V7.1 SP3 supports two license transports:
| Mechanism | Procedure | Pre-condition |
|---|---|---|
| USB License Key (Dongle) | Physically unplug the dongle and plug it into the new PC. The license becomes active after ALM re-detects the device. | The dongle is the bound medium. No virtual backup is possible. |
| Software License (file-based) | On the old PC, ALM → License Key → Transfer. On the new PC, install ALM, then ALM → License Key → Transfer back. Alternatively, use ALM → License Key → Back-up and restore. | The old PC may be reactivated by Transfer if the new PC is offline. |
| ASRT-PO Booking Back | If a software license is moved, Automation License Manager will report that the old PC no longer has the license. There is no CPU STOP penalty on the controller – the AS RT-PO license is a PC-side authorization, not a PLC-side stop condition. The PLC continues to execute the S7 program without interruption. | The PLC CPU is unaffected by the license move. |
Performance Expectations on a Pentium 4 Class PC
The Pentium 4 platform meets the readme minimum for V7.1 SP3 (CAS – Central Archive Server) and for an ES/OS single-user. Realistic performance figures during pre-commissioning:
| Task | Expected Performance | Mitigation |
|---|---|---|
| STEP 7 / CFC / SFC compile of a 200-function block project | 5-15 minutes per compile cycle | Compile during lunch / overnight runs; use incremental compiles |
| WinCC OS Runtime startup | 3-6 minutes cold start | Leave the OS in process mode rather than restarting frequently |
| Tag logging (1,000 external tags at 1 s) | Database growth of 0.5-1 GB per day | Reduce logging frequency to 5 s for slow variables; archive to D:\ |
| Alarm logging (2,000 active alarms/day) | Acceptable; WinCC dispatches without lag | Disable ring-buffer flushing; set retention to 7 days |
| Graphics screen change | 1-3 s – acceptable for commissioning but slow for production | Pre-cache screens in OS Project Editor |
Archive Management on a Constrained Disk
- Open WinCC Explorer → Tag Logging and Alarm Logging editors.
- Open the Archive Configuration and set the archive path to
D:\PCS7_Archives\<ProjectName>. - Reduce the archive retention period to 3-7 days for the temporary build.
- Enable Segmented Archives with daily segments, so each segment can be moved to external media without affecting the active database.
- Schedule a Windows task that runs WinCC Archive Connector or a manual copy script to move segments older than 24 hours to a USB drive or network share.
Verification Checklist After Installation
| Step | Expected Result | Pass/Fail Criterion |
|---|---|---|
| SIMATIC Manager launches | No DLL errors, no licence warnings | Main window displays within 30 s |
| Open the project in STEP 7 | All S7 programs visible | No “Cannot access” red icons |
| CFC/SFC libraries loaded | Master data library available | Master Data Library visible in SIMATIC Manager |
| OS Project Editor run | Generates WinCC database without error | Compile report: 0 errors |
| OS Runtime startup | Process mode shows standard picture | Top-of-screen alarm line responsive within 2 s |
| PLC online connection | Accessible via TCP/IP or MPI | Online view shows CPU in RUN |
| Alarm logging test | Trigger a forced alarm from CFC | Alarm appears in OS within 3 s |
| Tag logging test | Force a process tag value change | Value appears in trend view |
| License Manager – License Analysis | All required modules green | No red “missing license” entries |
Troubleshooting Matrix
| Symptom | Likely Cause | Remedy |
|---|---|---|
| Setup aborts with “Insufficient disk space” on C: | C: is still 20 GB; setup requires 2-3 GB free for staging | Resize C: to 30 GB or change install drive |
| WinCC OS Runtime cannot start – DCOM error 0x80070005 | DCOM permissions not configured | Run dcomcnfg, add "Everyone" to launch permissions for WinCC services |
| Compile errors referencing SFC Visualization | Optional component not installed | Re-run setup, add SFC Visualization, OR remove the SFC chart from the project |
| Alarm logging frozen on first alarm | MSDE database corrupt from interrupted power | Use WinCC Archive Configuration to repair; restore from previous good backup |
| License Manager reports "License not found" | USB dongle driver not installed; or ALM service stopped | Reinstall dongle driver; restart ALM service |
| CPU goes to STOP after download from new PC | Project version mismatch (V7.1 SP2 vs SP3) | Verify SP level on both PCs; do not mix SP levels in a single project |
| OS graphics red X placeholders everywhere | Picture cache not generated | Run OS Project Editor → Compile OS |
| Tag logging database does not write to D: | WinCC service still pointing to default C:\ path | Edit archive path in Tag Logging editor; restart WinCC Runtime |
Field-Proven Pre-Commissioning Workflow
- Install PCS 7 V7.1 SP3 on the temporary PC with the minimum component set (no Batch, no Route Control, no PDM unless required).
- Load the customer project archive (the *.zip or PCS 7 backup file) into the ES.
- Compile the S7 program in STEP 7 and CFC/SFC. Resolve any compile errors before going online.
- Download the program to the controller (AS). Use PLC → Download to Target System with the right CPU selected.
- Bring the controller to RUN. Verify on the OS that process values are updating.
- Use the OS Runtime for I/O checkout, loop tuning, and operator-screen validation.
- At end of each shift: export tag-logging segments and alarm-logging segments to external media.
- When the replacement PC arrives, install PCS 7 V7.1 SP3 to the equivalent component set, transfer the project, transfer the license, and continue commissioning without data loss.
Safety and Operational Notes
- Do not use the temporary PC as a long-term operator station. The Pentium 4's sustained IPC and disk throughput are below the safe-comfort threshold for a 24/7 production environment.
- Keep the temporary PC isolated from the plant network or behind a managed switch with a static IP until the project-specific network configuration is verified.
- Back up the project daily during the pre-commissioning phase. A Pentium 4 with a small C: partition has a non-trivial risk of running out of disk mid-write, which can corrupt the S7 project file.
- Document the license position (USB key serial number or license file hash) before moving it to the new PC. If the license is lost, Siemens Customer Support requires proof of entitlement.
Can PCS 7 V7.1 SP3 be installed on a PC with only 80 GB of hard disk?
Yes. The readme's 120 GB figure represents the recommended footprint for a fully loaded configuration including Batch, Route Control, and PDM. A basic ES/OS single-user install consumes approximately 19 GB. The functional limit is the free space on the C: partition (recommended 30 GB after repartitioning), not the total disk size.
Will the S7-400 CPU go to STOP if the ES license is transferred to another PC?
No. The AS RT-PO license is a PC-side authorization checked by STEP 7 / PCS 7 ES. The PLC CPU only goes to STOP if the S7 program itself contains a runtime authorization check, which is uncommon in V7.1 SP3 projects. The PLC continues running its scan cycle normally during a license move.
How do I transfer a software license from the temporary PC to the new workstation?
On the temporary PC, open Automation License Manager and use License Key → Transfer to move the license to a license file or to the new PC directly over the network. On the new PC, install ALM and use License Key → Transfer back. The temporary PC will report the license as missing, which is expected.
What is the recommended C: drive size for a temporary PCS 7 V7.1 SP3 install?
30 GB. This provides the 19 GB base install footprint plus 5-10 GB of headroom for Windows updates, swap, and engineering project files. Keep all runtime archives on a separate D: partition.
Can WinCC tag and alarm logs be stored on a separate drive to save space on C:?
Yes. In WinCC Explorer, edit the Tag Logging and Alarm Logging archive configuration and set the archive path to D:\PCS7_Archives. Enable segmented archives with daily segments so each completed segment can be backed up and deleted to reclaim disk space without disturbing the active database.