DriveMonitor for Siemens Micromaster: RS485 Connection Guide

Overview

DriveMonitor is the Siemens commissioning and diagnostic utility shipped with the legacy MICROMASTER 4th-generation (MM4) inverter family, including the MICROMASTER 420 (MM420), MICROMASTER 430 (MM430), and MICROMASTER 440 (MM440) drives. The application provides online parameter read/write, fault-history retrieval, firmware readout, trace recording, and a graphical control panel for start/stop and speed reference override.

DriveMonitor uses the Siemens USS protocol (Universal Serial Interface protocol) over an RS485 half-duplex bus for most MM4 commissioning tasks. A second path uses the PROFIBUS DP-V0 interface on MM430/MM440 with the optional PROFIBUS module (order code 6SE6400-1PB00-0AA0). For most engineers working at a bench or on a single drive, the RS485/USB path is the practical choice.

The remainder of this guide covers: drive-side wiring at terminals 29 and 30, parameter configuration for USS address and baudrate, RS485↔USB converter selection, DriveMonitor installation, and a verification procedure that confirms a clean online session.

Prerequisites

Before attempting a DriveMonitor session, verify the following hardware and software items are present.

Communication Path Selection

Three physical paths exist for connecting a PC to an MM4 drive. Each has different commissioning effort and reliability characteristics.

The Drive-PC kit is the officially supported path and eliminates most converter-related issues. When a kit is unavailable, an RS485 converter to either RS232 or USB is required because the MM4 exposes only RS485 on its user terminals (no native RS232 for the USS bus).

Drive-Side Wiring at Terminals 29 and 30

The MM4 control board carries the USS/RS485 interface on two screw terminals at positions 29 (P+, non-inverting) and 30 (N-, inverting) of the control terminal strip. A third terminal, 31 (functional earth / shield clamp), is the bonding point for the cable shield.

Step-by-step wiring

1. Power down the drive and wait five minutes for the DC bus to discharge. Confirm with a Cat III multimeter between DC+ and DC-; the reading must be below 5 V DC.
2. Open the lower front cover of the MM4 (two captive screws on MM440) to expose the control terminals.
3. Strip 8 mm of insulation from each conductor of the shielded twisted pair (Belden 3106A recommended).
4. Connect the positive (white/blue) conductor to terminal 29 (P+).
5. Connect the negative (blue) conductor to terminal 30 (N-).
6. Bond the cable shield to terminal 31 using the supplied shield clamp or a P-clip within 50 mm of the terminals.
7. Torque each terminal screw to 0.5 Nm.

RS485 Termination and Bias

For a single-drive, single-PC link (the most common DriveMonitor use case), terminate only at the two ends of the RS485 segment.

• At the drive: install a 120 Ω resistor across terminals 29 and 30 if MM4 parameter P2010 is set to RS485 Termination ON — accessible through P2010 = 1 on some firmware versions; verify with P2011 readback on MM440.
• At the converter: enable internal termination on the USB converter (typical DIP switch ON, ON, OFF for most Phoenix and Advantech units).
• If the drive is mid-bus on a multi-drop network, leave drive termination off and terminate only at the two physical end nodes.

Configuring USS Address and Baudrate on the Drive

Two MM4 parameters control the USS link. Both must match what DriveMonitor expects on the host side.

Use the Basic Operator Panel (BOP) or Advanced Operator Panel (AOP) to set the parameters above. From the BOP:

1. Press P to enter parameter mode.
2. Use the arrow keys to scroll to P2010, press P to access.
3. Set the index with the right-arrow key (index 0 for terminals 29/30), press P.
4. Scroll to the desired baudrate code (6 = 9600, 7 = 19200, 8 = 38400), press P to confirm.
5. Repeat for P2011, setting node address to 1.
6. Press Fn to exit back to the run display.

Converter and Driver Installation

USB converter path

1. Install the converter driver before plugging in the device. For FTDI-based units, download the WHQL-signed driver package (CDM21228 or later). For non-FTDI chips, prefer the OEM signed driver; never rely on Windows Update for VCP support on legacy OS images.
2. Plug in the converter and verify in Device Manager → Ports (COM & LPT) that a new COM port appears (for example COM4).
3. Note the assigned COM number — DriveMonitor will require this value.

RS232 converter path

1. Identify the COM port number in BIOS (legacy) or Device Manager.
2. Set the converter's DIP switches for DTE mode, echo off, and 120 Ω termination on.
3. Connect the converter's RS232 side to the laptop's DB-9 (use a null-modem adapter only if the converter is DCE-marked).

Installing DriveMonitor Software

1. Insert the STARTER / DriveMonitor DVD (order code 6SL3072-0AA00-0AG0 for the older 5.x series, or the Siemens support download portal for current releases).
2. Run setup.exe as Administrator.
3. Choose Custom Installation and enable DriveMonitor and STARTER → DriveMonitor bridge.
4. Accept the default installation directory (C:\Siemens\DriveMonitor).
5. Restart when prompted so the OPC and USS service daemons load.

The DriveMonitor manual is not a separate PDF — it is delivered as a compiled HTML help (DriveMonitor.chm) and is invoked from Help → Contents inside the application. This help is the canonical reference and is updated per firmware.

Establishing a DriveMonitor Online Session

1. Launch DriveMonitor from Start → Siemens Automation → DriveMonitor.
2. From the menu choose Online → Connect to target system (or press F5).
3. In the Connect to target system dialog, select the PC-COM tab.
4. Set:
   • COM port: the COM number from Device Manager (e.g., COM4)
   • Baudrate: must match P2010 on the drive (e.g., 19200)
   • Address: must match P2011 on the drive (e.g., 1)
5. Click OK. The status bar should report Online (USS) within 3–5 seconds.
6. Double-click any parameter in the parameter list to confirm read/write round-trip.

Verification

Once DriveMonitor reports Online (USS), run the following verification sequence:

1. Parameter read-back: open parameter list, navigate to r0010 (drive output frequency). The reported value must reflect the current setpoint within 0.1 Hz. If the value is stuck at 0.00 Hz, the USS telegram is read but the process data (PZD) channel is broken — check P2014.
2. Fault buffer check: navigate to r0947[0..7] (fault code history). Confirm no F0070 (USS telegram failure) or F0071 (USS telegram off) entries appear after a 60-second idle period.
3. Write test: change P0010 to 30 (factory settings) and back to 0 (ready). The status LED on the drive must transition from yellow (commissioning) to green (run-ready) without faults.
4. Control word test: in the DriveMonitor control panel, click Run. The drive must respond within 200 ms with a green status indicator. Click Stop to verify coast-down.
5. Trace recording: open Trace → New trace, record r0021 (actual RPM) for 10 seconds. The trace must be continuous; dropouts indicate intermittent bus errors.

Troubleshooting Matrix

Related Tools and Documentation

DriveMonitor is part of the broader Siemens drive commissioning ecosystem. For legacy MASTERDRIVES and SIMOREG platforms, the DriveMonitor 1.x utility was distributed with firmware CDs and is referenced in the Siemens support entry listed below. For SINAMICS G110/G120/G120C drives (the modern equivalent of MM4), the DriveMonitor concept has been replaced by STARTER and the webserver built into SINAMICS G120 with the CU250S-2 control unit. The ABB DriveMonitor product is a separate, ABB-specific software agent and is not interchangeable with the Siemens utility described here.

• Siemens DriveMonitor entry and attachments: Siemens MASTERDRIVES / SIMOVERT DriveMonitor PDF
• MICROMASTER 440 Operating Instructions (current revision on Siemens support portal): referenced by order code 6SE6400-5AW00-0BP0.
• USS protocol manual: 6SE7080-AKB60 (Siemens drive interface protocol reference, USS specification).

Safety and Field-Commissioning Notes

• Always isolate and lock the input power before opening the MM4 control terminal cover. The drive's DC bus remains energized for up to five minutes after power removal.
• Do not connect the shield to terminal 31 on more than one drive — this creates a ground loop. Bond the shield at one end only.
• When commissioning a motor for the first time, leave the motor uncoupled from the load. Use DriveMonitor's Control panel to apply a small speed reference (e.g., 5 Hz) and verify rotation direction before reconnecting the load.
• Save the final parameter set with DriveMonitor's Upload to file (DMP-format). The upload includes P0010 through P3999 and is the recommended method to clone settings between identical drives.