Installing SIMATIC Step 7 V5.5 and WinCC Flexible on Windows 7 for S7-200 / KTP 600 DP Programming

Field engineers still maintain a large installed base of SIMATIC S7-200 CPUs (CPU 221, 222, 224, 224XP, 226) paired with KTP 600 DP Basic Panels programmed with WinCC Flexible. Because the programming toolchain (STEP 7 Micro/WIN V4.0 and WinCC Flexible 2008) was originally targeted at Windows XP, moving to a Windows 7 engineering laptop is a common commissioning hurdle. This reference consolidates the official Siemens compatibility matrix, the correct PG/PC Interface parameter assignment for the PPI / MPI cable, and the verified cable topology between the CPU 200 and the KTP 600 DP.

The guidance below is intended for engineers who need to bring up an existing S7-200 program and an existing KTP 600 DP project on a Windows 7 (32-bit or 64-bit) notebook when no legacy Windows XP machine is available.

1. Software Stack Required for S7-200 + KTP 600 DP

2. Windows 7 Compatibility for the SIMATIC Toolchain

Siemens publishes the official compatibility matrix through the Compatibility Tool on the Siemens Industry Online Support portal:

Siemens SIMATIC Compatibility Tool

Always run your target versions through this tool before installing. The matrix below summarizes the release-state of the products most commonly used with the CPU 200 + KTP 600 DP combination.

*Windows 10 64-bit is workable on Micro/WIN V4.0 SP9 only when launched "Run as Administrator" and when the USB-serial converter driver is signed for Win10. Treat Windows 10 as outside the tested matrix for production deployment.

3. STEP 7 V5.5 – Installation Requirements on Windows 7

The discussion referenced the canonical Siemens FAQ "What are the requirements for installing STEP 7 version V5.5?". The required environment on Windows 7 is:

• Operating system: Windows 7 Professional, Ultimate or Enterprise (32-bit or 64-bit). Starter and Home editions are not supported.
• User context: local administrator account; UAC disabled for the install session.
• RAM: minimum 1 GB (Win7 32-bit) / 2 GB (Win7 64-bit).
• Free disk: ~3 GB for STEP 7 V5.5 base + Service Pack.
• Required redistributables (auto-installed by the V5.5 setup): Microsoft Message Queuing (MSMQ) and the SIMATIC diagnostic interface.
• Display: 1024 × 768 minimum, 65536 colors. Small fonts mode not supported.

Install sequence for a clean Windows 7 PC that must host both STEP 7 V5.5 (for S7-300/400 work) and Micro/WIN V4.0 SP9 (for S7-200 work):

1. Insert the STEP 7 V5.5 DVD; launch Setup.exe as administrator.
2. Accept the licence, choose Installation: STEP 7 plus the S7-200 option set if you plan to use wizards for S7-200 (only available in the Asia-Pacific localised build).
3. Install the latest Hotfix (HF) that ships with the DVD2 image.
4. Reboot.
5. Insert Micro/WIN V4.0 SP9; run Setup.exe as administrator. Accept the default folder C:\Program Files\Siemens\STEP 7 MicroWIN V4.0.
6. Install the PPI / MPI USB driver that ships with the S7-200 PC Adapter (USB/PPI) when prompted.
7. Reboot. Confirm that "SIMATIC Manager" and "STEP 7-Micro/WIN" both appear in the Start menu.

4. WinCC Flexible 2008 on Windows 7 – Install Notes

WinCC Flexible 2008 SP5 (Standard or Advanced) is the supported configuration tool for the KTP 600 DP (Basic Panel, 6"). On Windows 7:

• Choose WinCC Flexible 2008 SP5 – earlier service packs will install on Windows 7 but the HMI transfer / simulation will fault.
• Disable UAC before installation (otherwise the transfer channel will fail with "The handle is invalid (0x80070006)" when the runtime tries to enumerate the USB-serial COM port).
• Install under a local administrator account, not a roaming profile – WinCC Flexible stores licences in C:\ProgramData\Siemens\Automation\ and roaming redirection will break re-activation.
• If a "Can I buy the upgrade version and install it on a new pc without any installation from Step7 before?" scenario applies, the answer is yes provided a valid licence key is transferred with the Automation License Manager (ALM). A clean machine without prior STEP 7 still accepts the upgrade.

5. PG/PC Interface – Parameter Assignment for the PPI Cable

The single most common Windows 7 fault reported when bringing up an S7-200 station is the error "Could not open the interface to the PPI cable" raised from the PG/PC Interface dialog. The error is generated because Windows 7 plugs the USB-serial bridge into a different COM port number every reboot, and Micro/WIN still points at the original COMx.

Procedure to configure the interface correctly:

1. Plug the USB/PPI cable into a free USB port. Open Device Manager → Ports (COM & LPT). Note the new entry, e.g. USB Serial Port (COM4).
2. Start Micro/WIN. Open the left navigation pane and click Set PG/PC Interface (or use the menu Tools → Set PG/PC Interface).
3. In the dialog, choose PC/PPI cable (PPI) from the Interface Parameter Assignment Used list. Click Properties.
4. On the PPI tab: address = 0, timeout = 1 s, transmission rate = 9.6 kbit/s for legacy CPUs or 19.2 kbit/s for CPU 224XP / CPU 226 with newer firmware.
5. On the Local Connection tab: select the COM port identified in step 1. Transmission rate must match the PPI tab. Set the cable selection to USB/PPI Multi-Master Cable if your cable is the USB variant, otherwise RS-232/PPI Multi-Master Cable.
6. Click OK, then OK again. The PG/PC Interface dialog closes and the assignment is stored in C:\Program Files\Siemens\STEP 7 MicroWIN V4.0\S7MicroWin.ini.
7. Click the Communications icon in Micro/WIN and run Double-click to refresh. The connected CPU address should appear (default is address 2 for a factory CPU).

6. PPI vs. MPI – Which Cable for S7-200 → KTP 600 DP?

The KTP 600 DP (6" Basic Panel, DP suffix) exposes an RS-485 MPI/PROFIBUS-DP port on the back. The S7-200 CPU 224XP / 226 exposes a single RS-485 port that supports either PPI or MPI (MPI as of firmware 1.2 and later). A direct PPI cable is the supported point-to-point link between the two devices.

Recommended approach: use the MPI cable (6ES7 901-0BF00-0AA0) for commissioning. Wire pins 3 (Data B), 8 (Data A) and 5 (GND) only – the cable is a passive 1:1 RS-485 link, no termination required when used point-to-point. The CPU 200 is the master, the KTP 600 DP is the slave. Default MPI address of the KTP 600 DP is 1; the CPU is 2.

7. WinCC Flexible – Connecting to KTP 600 DP via PPI/MPI

To configure the HMI project for PPI/MPI communication:

1. Open the project in WinCC Flexible 2008. In the project tree, expand Connections; double-click the existing connection (default name: Connection_1).
2. Set the Communication driver to SIMATIC S7-200. WinCC Flexible automatically switches the port parameters to PPI.
3. Set HMI device address = 1 (KTP 600 DP), PLC device address = 2 (CPU 200). Network profile = PPI, Baud = 187.5 kbit/s when the network is MPI.
4. On the CPU side, in Micro/WIN open System Block → Communications Port. Set the address to 2 and the baud to match the WinCC Flexible side (9.6 kbit/s PPI or 187.5 kbit/s MPI).
5. Compile the WinCC Flexible project, then start Transfer → HMI OS Update / Transfer. Choose Serial / PPI / MPI. Set the PC COM port and baud, click Transfer.

8. Known Errors on Windows 7 – Quick Fix Matrix

9. Verifying the Installation

Use this end-to-end smoke test before handing the workstation back to the user:

1. Toolchain presence: Start → All Programs → Siemens Automation → SIMATIC → STEP 7-Micro/WIN V4.0. The splash screen must report "V4.0.9.x". Repeat for SIMATIC Manager and WinCC Flexible 2008.
2. Licence: Start → Siemens Automation → Automation License Manager. Verify the activation of Micro/WIN V4.0, WinCC Flexible 2008 (KTP 600 DP option) and STEP 7 V5.5.
3. CPU 200 communication: Micro/WIN → Communications → "Double-click to refresh". The CPU 224XP at address 2 must respond with firmware string "CPU 224XP REL 02.xx".
4. HMI communication: WinCC Flexible → Transfer → HMI OS Update. The transfer should report "Transfer completed successfully" within 10 s for a 1 MB project.
5. Round-trip: Force a tag from Micro/WIN (e.g. set QB0 = 0xAA). The KTP 600 DP must display the new value on the connected screen within 1 s, confirming that the PPI/MPI link is healthy end-to-end.

10. Alternate Platform Notes

If a true Windows XP machine is unavailable and Windows 7 cannot be stabilised, the supported fallback options are:

• Windows XP Mode on Windows 7 Professional/Enterprise/Ultimate – runs Micro/WIN V4.0 inside an XP virtual machine; the USB/PPI cable is forwarded via RDP USB mapping.
• VirtualBox / VMware with a Windows XP SP3 guest – attach the USB/PPI cable to the guest, install Micro/WIN inside the guest. Use this when the host OS is Windows 10.
• Re-target the project to a TIA Portal / WinCC Comfort project and migrate the S7-200 to a S7-1200 if the system is end-of-life – the KTP 600 DP is not supported in TIA Portal and must be replaced with a KTP 700 / KTP 900 Basic Panel.

11. Frequently Asked Questions