Resolving ProSave USB Connection Missing for TP170 Micro Upload

1. Problem Overview

When commissioning or maintaining a Siemens SIMATIC TP170 Micro panel, engineers frequently attempt a project upload (backup) using SIMATIC ProSave and the USB/PPI Multi-Master Cable (6ES7 901-3DB30-0XA0). The expected workflow is: connect cable → launch ProSave → select Device Type → select Connection "USB" → choose Panel → click "Upload" (Restore from panel).

The reported failure is that the Connection drop-down only displays "Serial", not "USB". Because the engineer is physically using a USB-attached cable, the absence of the "USB" option appears to be a software bug or configuration gap. In practice the symptom is almost always caused by one of three conditions:

1. The TP170 Micro does not have a USB interface on the device itself. The TP170 Micro is a legacy PPI (RS-485) panel. Any "USB" entry in ProSave refers to USB-to-PPI bridging, which is only present in ProSave when the chosen panel supports USB natively (e.g. TP177, OP177, Comfort panels).
2. The installed ProSave version does not include the TP170 Micro under its USB/PPI driver manifest. Earlier builds (V7.0 / V7.2) only support serial transfers for legacy TP170 Micro devices. Full USB upload over the 6ES7 901-3DB30-0XA0 cable requires ProSave V7.4.0.0 or later combined with the correct cable SKU and firmware.
3. The cable driver (S7USB / PC Adapter USB) is not installed, so ProSave defaults to the only transport it can guarantee – serial COM via a virtual COM port.

2. Hardware Identification: TP170 Micro and Cable Variants

The TP170 Micro family comprises three variants; each uses the same PPI/MPI physical interface but differs in display backplane and memory size:

The 9-pin sub-D male connector on the back of the panel carries PPI (Point-to-Point Interface) signalling at 187.5 kbit/s or 19.2 kbit/s, with the panel acting as slave (address 1 by default, configurable from 1 to 31).

2.1 USB/PPI Multi-Master Cable (6ES7 901-3DB30-0XA0)

The order number 6ES7 901-3DB30-0XA0 (also written 6ES7901-3DB30-0XA0) is the USB/PPI Multi-Master cable. Key characteristics:

3. ProSave Connection Type Architecture

ProSave's "Connection" drop-down is dynamically populated based on three criteria evaluated at run-time:

1. Selected Device Type – ProSave filters supported transports per panel. TP170 Micro entries appear under the "TP170" device class.
2. Installed ProSave Build – Newer builds add USB transports for legacy panels; older builds cap at serial/modem/Ethernet.
3. Available System Drivers – If the S7USB driver is missing, the "USB" radio option is greyed out regardless of build.

For the TP170 Micro, the transport menu will normally expose:

• Serial – PPI/MPI via virtual COM (the 6ES7 901-3DB30-0XA0 cable is enumerated as COMx by the S7USB driver, so the upload still appears as "Serial" in the menu while the physical layer is USB).
• Modem – for remote transfer over PSTN or GSM.
• Ethernet / TCP/IP – only available if the TP170 Micro has been retrofitted with an Ethernet option (TP170 Micro does not have on-board Ethernet; requires an external RS-485 to Ethernet converter or PC-Adapter Ethernet).

This is why the menu shows only "Serial" for a TP170 Micro: the panel-side interface is RS-485 regardless of whether the PC-side plug is USB or DB-9. The label "USB" in ProSave is reserved for panels with on-device USB host ports (e.g. OP177B, TP177B, TP/OP277, Comfort).

4. Root Cause Decision Matrix

5. Solution Path A – Direct Serial/PPI Upload (Most Reliable)

The path with the highest success rate on legacy TP170 Micro hardware is to keep the ProSave connection set to "Serial" but ensure the virtual COM port from the USB cable is selected correctly.

5.1 Prerequisites

• ProSave V7.4 or newer installed (component of WinCC flexible 2008 SP5 / TIA Portal V13 HSP).
• USB/PPI cable 6ES7 901-3DB30-0XA0 OR serial/PPI cable 6ES7 901-3BF21-0XA0.
• Siemens S7USB driver installed (auto-installed with ProSave; manual install via Setup.exe in ProSave install medium under "Drivers\S7USB").
• TP170 Micro powered, DIP switches default (PPI slave, addr 1).

5.2 Procedure

1. Power on the TP170 Micro; allow 30 s for boot.
2. Connect the cable's USB plug to the engineering PC; allow Windows to enumerate. Note the COM port assigned (e.g. COM4).
3. Launch ProSave from Start → SIMATIC → ProSave.
4. In the General tab, set Device Type → TP170micro.
5. In the Connection tab, choose Serial as connection mode (this is correct – it refers to the PPI segment).
6. Select Port = the COM port assigned in step 2 (e.g. COM4).
7. Set Baud rate = 187.5 kbit/s (default for TP170 Micro).
8. Set Profile = PPI.
9. Click Test. ProSave should return "Connection OK". If it fails, jump to Section 9 (Diagnostics).
10. Switch to the Backup tab (or Restore for upload from panel).
11. Tick Complete backup, choose destination folder, click Start Backup / Start Restore.

6. Solution Path B – ProSave Version Upgrade

If Path A still fails or ProSave does not list the TP170 Micro at all, the ProSave version in use is missing the legacy panel manifest. Siemens published FAQ support.industry.siemens.com entry 10347815 documenting the panel-to-cable compatibility matrix; FAQ 11017496 describes the corresponding ProSave update procedure.

6.1 Required ProSave Build

6.2 Upgrade Procedure

1. Obtain the ProSave installer from the WinCC flexible 2008 SP2 / SP3 / SP5 installation medium, or from the Siemens KB entry support.industry.siemens.com 11017496.
2. Close all SIMATIC applications.
3. Run Setup.exe from the ProSave install folder. Use "Repair" or "Modify" if already installed.
4. Ensure the S7USB driver and WinCC flexible – ProSave Panel Plugin components are ticked.
5. Reboot Windows.
6. Verify new build: Help → About ProSave. Build string must read ≥ V7.4.0.0_xxx.

7. Solution Path C – Using a Serial/PPI Cable (No USB Confusion)

If the PC has a built-in RS-232 (COM1) port – common on older engineering laptops or via a USB-to-RS232 dongle on modern hardware – the legacy cable 6ES7 901-3BF21-0XA0 provides a transparent COM-to-PPI link without any USB drivers. This eliminates the "USB option" confusion entirely and is preferred for bench uploads in service shops.

Configuration parameters in ProSave:

• Connection = Serial
• Port = COM1 (or COM3/COM4 from USB-to-RS232 adapter)
• Baud rate = 187.5
• Profile = PPI

8. Driver Verification – S7USB Install Check

The S7USB driver creates the virtual COM port that ProSave uses for the USB/PPI cable. Without it, ProSave still shows "Serial" but lists no port, or returns error 0x0312 / 0x0310.

1. Open Device Manager (devmgmt.msc).
2. Expand Ports (COM & LPT).
3. Look for Siemens PC USB Adapter or S7USB device.
4. Note the assigned COM number.
5. If missing: right-click → "Scan for hardware changes"; or manually install from C:\Program Files\Siemens\Automation\ProSave\Drivers\S7USB\Setup.exe.
6. Confirm the driver version is ≥ V2.0.2 (Windows 7 / 10 compatible).

9. Diagnostic Workflow When Upload Still Fails

9.1 Common ProSave Error Codes

10. Configuring the Panel PPI Address

If the panel's PPI address has been changed, ProSave must match. The TP170 Micro PPI address is configured via the control panel Start → Settings → Control Panel → Set PG/PC Interface on the device itself:

1. On the panel, press Start → Settings → Control Panel → Transfer (or Communication).
2. Note PPI address (default 1) and baud rate (default 187.5).
3. Match these in ProSave's serial connection settings.

11. Migrating the Uploaded Project

Once the backup is extracted (typically a .pdb or .pdz file for ProTool projects, or a .hmi compressed folder for WinCC flexible), engineers usually want to reverse-engineer the project:

• Use ProTool V6.0 SP3 or WinCC flexible 2008 SP5 to open / convert the backup.
• For migration to TIA Portal V13 or later, use WinCC flexible's File → Migrate Project; TP170 Micro projects migrate to TP700 Comfort after warning.
• Some tag references, screen animations, and historical alarm logs may not survive the migration; verify by stepping through screens.

12. Verification Checklist

Confirm the upload was successful before removing the panel from service:

• Backup file size is reasonable (≥ 200 kB for a small ProTool project; ≥ 1 MB for a populated WinCC flexible project).
• Opening the backup in WinCC flexible / ProTool produces no warnings about missing references.
• Number of screens, tags, and alarms in the backup matches the panel's project summary.
• Restore the backup to a second panel of the same type to confirm round-trip integrity.

13. Field-Proven Caveats

• USB cable on USB-3 ports: Some engineering PCs with USB-3 controllers (Renesas, Fresco Logic) have known compatibility issues with the legacy S7USB driver. Use a USB-2 hub or USB-2 port.
• Y-cable required for some older PCs: USB ports that cannot source 500 mA may require a powered hub between the PC and the 6ES7 901-3DB30-0XA0 cable.
• TP170 Micro vs. TP170A/B: The TP170 Micro is a separate device family. Selecting TP170A or TP170B in ProSave causes a 0xE001 error.
• Multi-master cable is fine for transfer: The "Multi-Master" suffix of 6ES7 901-3DB30-0XA0 refers to PPI segment behaviour, not USB topology. The cable is appropriate for a single panel upload even though it supports multi-master on the PPI side.
• Replacing the panel: If the TP170 Micro has failed and a TP177 is used as a substitute, ProSave will show a different transport menu – the project must be migrated to the new panel in ProTool/WinCC flexible.
• Password protection: A TP170 Micro project protected with ProTool passwords cannot be uploaded without the password. ProSave will prompt; entering an incorrect password nine times locks the panel.

14. Recommended Tool Stack

15. Frequently Asked Questions