CP5512 PPI Interface Missing for S7-200: STEP 7 Micro/Win Fix

Problem Statement

Field engineers maintaining legacy S7-200 systems frequently encounter a situation where the CP5512(PPI) interface entry is absent from the PG/PC Interface dialog in STEP 7 Micro/Win, even though the CP5512 PCMCIA card is correctly installed in the laptop and recognized by the operating system. The interface list shows only CP5512(Auto), CP5512(FWL), CP5512(MPI), and CP5512(PROFIBUS), and the standard PPI programming path is therefore unavailable. Typical symptoms include:

• CP5512 entries visible: CP5512(Auto), CP5512(FWL), CP5512(MPI), CP5512(PROFIBUS)
• CP5512(PPI) entry missing from the selection list
• Standard USB/PPI or PC/PPI cable cannot be selected when the CP5512 is set as the active access point
• STEP 7 Micro/Win reports "Cannot establish connection to S7-200" with the active CP5512 interface
• Online → Upload/Download actions fail with timeout 30s error

This issue has been reproduced on installations of STEP 7 Micro/Win V3.2 combined with STEP 7 V5.4, where the Micro/Win installer did not register the PPI-specific CP5512 access point driver in the Windows registry. The documented workaround requires an ordered install/reinstall sequence, as confirmed by field technicians working on CPU 216, CPU 224, and CPU 226 systems. The same root cause applies to S7-200 SMART, although that platform uses Micro/Win SMART and a different driver stack that is out of scope here.

CP5512 Hardware Overview

The Siemens CP 5512 (Siemens part number 6GK1551-2AA00) is a PCMCIA Type II communications card designed to program SIMATIC S7-200, S7-300, S7-400, and C7 controllers from a laptop. It exposes a 9-pin D-sub PROFIBUS connector on its PCMCIA sled and supports the following protocols:

• MPI (Multi-Point Interface) up to 187.5 kbps; 1.5 Mbps with PROFIBUS profiles
• PROFIBUS DP master and slave up to 12 Mbps
• PPI (Point-to-Point Interface) — the proprietary Siemens protocol used by S7-200 CPUs at 9.6 kbps and 19.2 kbps
• FWL (Firmware Loader) — a maintenance mode for PROFIBUS CP firmware updates

CP5512 was discontinued and replaced by CP 5711 (USB) and CP 5602 (PCIe) for new deployments, but the card remains widely deployed in maintenance fleets supporting S7-200 hardware still in service. PPI protocol support is a software/driver feature on CP5512, not a hardware limitation. Whether PPI is exposed as a selectable PG/PC interface depends entirely on whether the Micro/Win installer (or the corresponding component of STEP 7) has registered the PPI access point with the Windows registry.

Why CP5512(PPI) Disappears from PG/PC Interface

The PG/PC Interface dialog in Micro/Win is populated from the Windows registry under HKEY_LOCAL_MACHINE\SOFTWARE\Siemens\AUTSW\PGPCInterface on 32-bit installations. On 64-bit Windows running 32-bit Micro/Win, the keys are mirrored under Wow6432Node. The CP5512 PPI driver is installed by the Micro/Win setup routine and registered as a subkey. Several conditions cause the PPI entry to be missing:

1. Micro/Win V3.2 with STEP 7 V5.4 coexistence. The V3.2 setup predates full CP5512 PPI driver integration; it registers MPI and PROFIBUS drivers but not PPI. The coexistence install sequence with STEP 7 V5.4 can suppress the PPI registration when STEP 7 is installed after Micro/Win, even though Micro/Win was V3.2 capable of attempting the registration.
2. Improper uninstall order. If STEP 7 is uninstalled before Micro/Win, the PPI driver registry keys may not be removed cleanly, leaving partial entries that point to a deleted DLL.
3. Corrupted driver registration. Manual removal of the PCMCIA card, BIOS power management transitions, or certain Windows updates can clear the Set\PPI\CP5512 subkey without re-registering it on next boot.
4. Missing Micro/Win V4.0 components. The PPI driver for CP5512 is delivered with the Micro/Win V4.0 SP2 (or later) installer. Earlier versions — including V4.0 SP0/SP1 — may register the entry but with a DLL version mismatch that prevents the access point from being selected.
5. Conflict with newer SIMATIC NET PC Software. If SIMATIC NET PC Software V8 or later is installed for PC Station use, its CP5512 access points can override the Micro/Win registration, and Micro/Win V3.2 will not re-register the PPI entry.

Resolution: Step-by-Step Driver Reinstall Procedure

Use this ordered procedure to restore the CP5512(PPI) interface entry. The procedure was validated against Micro/Win V4.0 SP2–SP9 and STEP 7 V5.4 SP3/V5.5 on Windows XP SP3, Windows 7 32-bit, and Windows 7 64-bit running 32-bit Micro/Win.

1. Back up the project and serial-number authorization. Copy C:\Program Files\Siemens\MicroWin\ project files and the *.MMC authorization disk image to external media. If Micro/Win is installed on C:\Siemens\, copy that folder as well.
2. Uninstall STEP 7 V5.4 via Control Panel → Add or Remove Programs. Confirm the "Communication Settings" component is also removed when prompted. Reboot when prompted.
3. Uninstall Micro/Win V3.2 via Control Panel → Add or Remove Programs. If a separate Micro/Win ToolBox is installed, remove it as well. Reboot when prompted.
4. Verify removal. Open PG/PC Interface. The CP5512 entries may still appear in the list because the registry keys are not always purged by the uninstaller. This is expected; do not delete them manually.
5. Install Micro/Win V4.0 (SP2 or later recommended; SP9 is the last released service pack for V4.0). Note that the Micro/Win installer registers CP5512(PPI), CP5512(MPI), CP5512(PROFIBUS), and CP5512(Auto) as separate access points. Reboot when prompted.
6. Install STEP 7 V5.4 (or V5.5). The STEP 7 installer overwrites some shared COM access points but preserves the CP5512 entries added by Micro/Win V4.0. If a custom install is offered, accept the default Communication Settings component.
7. Reboot a final time.
8. Open Micro/Win V4.0 → Communications → PG/PC Interface. The list must now contain the CP5512(PPI) entry. If it does not, proceed to the Registry Repair section below.

Registry Repair (Advanced)

If the CP5512(PPI) entry still does not appear after the ordered reinstall, verify the registry manually. This is a service-level operation and should be performed only by personnel familiar with the Windows registry. Always back up the registry before editing.

1. Open regedit as administrator.
2. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Siemens\AUTSW\PGPCInterface\CP5512.PPI.1 (or the equivalent Wow6432Node path on 64-bit Windows).
3. Verify the DriverDLL value points to a valid DLL, typically C:\Program Files\Siemens\MicroWin\Drivers\PPI\CP5512PPI.dll.
4. If the subkey is missing, export a working key from a known-good machine and import it, or reinstall the Micro/Win V4.0 communication component via the setup repair mode.
5. Reboot after any registry change.

Verification

After completing the procedure, perform the following checks before going on-site:

1. Interface list check. Open PG/PC Interface in Micro/Win V4.0. Confirm the CP5512(PPI) entry exists. Click Properties and verify the PPI network parameters (station address, baud rate, timeout, retries).
2. Diagnostic test. From Micro/Win, select Communications → Double-Click to Refresh. The connected S7-200 CPU should appear in the discovered devices list within 5–10 seconds.
3. CPU 216 validation. The reference field test was performed on a CPU 216 with the CP5512 inserted in a Toshiba Tecra laptop and a standard PPI network at 9.6 kbps. The CPU was discovered on the first poll, and online upload/download completed without timeout.
4. Driver version check. In Device Manager → PCMCIA adapters → Siemens CP 5512, the driver should report version 4.0.x.x or later, matching the Micro/Win installation. If the driver reports a V3.2 version, the PCMCIA driver was not upgraded; re-run the SIMATIC NET setup.
5. Loopback test. Disconnect from the S7-200, connect the CP5512 to a known-good CPU on the bench, and run Communications → Upload from CPU. The upload should complete within 30 seconds for typical program sizes.

CP5512 Interface Variants Reference

PPI Connection Parameters for S7-200

Default PPI parameters when using CP5512 with a CPU 21x or 22x S7-200:

Verify CPU-side PPI settings with Micro/Win under System Block → Communication Ports. Mismatched baud rate is the most common cause of "All connection attempts failed" errors when the CP5512(PPI) entry is otherwise correct. If a CPU 226 is used, port 0 and port 1 can be set independently; ensure the port connected to CP5512 is the one configured for PPI and not for freeport/user mode.

FWL (Firmware Loader) Interface Explained

FWL stands for Firmware Loader. It is a dedicated maintenance access point used to push firmware updates to a PROFIBUS CP module (for example, CP 342-5, CP 443-5, CP 443-1, ET 200S interface modules, or Y-Link). FWL is not used to update CPU firmware — the S7-200 CPU firmware is updated via PPI using Micro/Win's PLC → Firmware Update command, and the S7-300/400 CPU firmware uses a separate SIMATIC Manager procedure over MPI.

To use FWL, the target module must be in firmware-update mode, which is normally entered by holding the appropriate button combination or via a special PROFIBUS command. The FWL access point is delivered by STEP 7 setup; if it disappears after a Micro/Win reinstall, it can be restored by running the STEP 7 setup in repair mode with the Communication Settings component selected.

CP5511 vs CP5512: PPI Capability Clarification

Field sources occasionally state that CP5512 does not support PPI and that only CP5511 does. The case is more nuanced and worth a decision path rather than a flat rule:

• The CP5512 hardware is capable of running PPI; the bus interface is identical to CP5511, and the protocol stack is software-driven.
• PPI access point registration is a software concern. Micro/Win V3.2 does not register the CP5512(PPI) entry; Micro/Win V4.0 SP2 and later do.
• CP5511 (6GK1551-1AA00) is a parallel-port version of the same card and historically came with broader legacy driver support, which is the source of the misconception that CP5511 is the "PPI" card.
• CP5511 also requires the parallel port to be configured in ECP/EPP mode in the laptop BIOS for reliable operation. CP5512 does not have this constraint.

Decision path: If your Micro/Win version is V4.0 SP2 or later and the CP5512(PPI) entry is visible after the reinstall procedure, use the CP5512. If the entry cannot be made to appear after exhausting the reinstall and registry-repair steps, fall back to a USB/PPI cable (6ES7901-3DB30-0XA0) as a temporary workaround. The USB/PPI cable appears as PC/PPI cable (USB) in the PG/PC interface and is a reliable S7-200 programming path. For long-term fleet planning, migrate to CP5711 (USB) or to S7-1200 with TIA Portal — both paths avoid the legacy CP5512 driver stack entirely.

Common Error Messages and Interpretation

Troubleshooting Matrix

Field Commissioning Notes

• Always power the S7-200 CPU before inserting the CP5512 into the PCMCIA slot, and verify the PPI network is terminated (220 Ω at both ends, switch on the CPU and on any EM 277 or EM 241 modems present on the segment).
• On a multi-drop PPI segment, the CP5512 must be assigned a unique master address; address 0 is the default and is normally used. S7-200 CPUs occupy addresses 2 through 31; reserve 0 for the programming device.
• If a USB/PPI cable is used as a fallback, the cable's own DIP switches must be set to PPI mode (switch 5 = 1) and the local address must not collide with any CPU on the segment. The USB/PPI cable is itself a PPI master at the address set on its DIP switches.
• CP5512 is not hot-swappable. Insert the card only when the laptop is fully booted, and remove it before standby or hibernate to avoid driver reset issues. Configure the laptop power profile to disable PCMCIA power-down.
• For new deployments targeting S7-200, prefer CP5711 (USB) or migrate to S7-1200 with TIA Portal — both paths avoid the legacy CP5512 driver stack entirely and are supported on current Windows versions.
• On Windows 7 64-bit, run Micro/Win V4.0 in XP Mode or in a 32-bit virtual machine, because the 64-bit Micro/Win does not support CP5512. The CP5512 driver is 32-bit and does not have a 64-bit equivalent.
• Document the installed Micro/Win service pack (SP2, SP3, ..., SP9) and the STEP 7 service pack in the project folder. Driver issues are far easier to diagnose when the exact versions are recorded.

For official Siemens support, register the S7-200 site and CP5512 serial number at Siemens Industry Online Support and search the knowledge base for CP5512 PPI MicroWin — Siemens has published several FAQ entries covering this scenario. The CP5512 manual (printed matter number 6GK1551-2AA00) documents the protocol list and the LED diagnostics, but it does not cover the PG/PC Interface registration procedure; that information is in the Micro/Win online help and in the STEP 7 installation manual.

FAQ