Resolving F06200 Infeed Fault on SINAMICS S120 Active Line

Overview

The SINAMICS S120 drive system with an Active Line Module (ALM) performs automatic line identification on first commissioning and after certain configuration changes. When this identification fails, drive object INFEED raises fault F06200 — Infeed: Line supply identification unsuccessful. On SIMOTION D435-2 controllers with CX32-2 extensions, the fault is reported through the cyclic PROFIBUS/PROFINET interface and halts the infeed (Line Module) from transitioning to RUN. This article dissects a real commissioning case built around a 16 kW Active Line Module (6SL3130-7TE21-6AA4), an Active Interface Module (6SL3100-0BE21-6AB0), and a top-hat line filter (6SL3000-0BE21-6DA0), and documents the field-proven recovery procedure.

Affected System Topology

The reported installation is a SIMOTION D435-2 DP/PN motion controller with a CX32-2 controller extension, controlling a SINAMICS S120 booksize drive line-up. The full bill of materials is summarized below.

Note that no Voltage Sensing Module (VSM, e.g. 6SL3053-0AA00-3AA1) is fitted. This is a critical detail because Active Line Modules from firmware V4.x onward can identify the line either via the VSM or, on units with integrated measurement in the AIM, via direct measurement at the AIM terminals. The configuration parameter p0221 selects the source.

F06200 — Fault Definition and Reaction

F06200 is listed in the SINAMICS S120/S150 List Manual (LH1) under faults of drive object INFEED. Its canonical description is:

Infeed: Line supply identification unsuccessful — the characteristic line data could not be measured to the required accuracy within the maximum identification time.

The fault belongs to fault class FAULT_BUFFER (Class 3) with default reaction OFF2. The reaction can be reparameterized through p2100[0]/p2101[0], but suppression is not recommended because the ALM cannot reliably operate without valid line data.

The accompanying information message that appears during the identification attempt is:

• A06400 — Infeed: Line supply identification selected / active

The presence of A06400 on every cold start is normal; the ALM always performs line identification during the transition from commissioning mode (p0010 ≠ 0) or after a download. What is abnormal is the ALM then raising F06200 instead of clearing A06400 with a successful identification.

Root Cause Analysis

F06200 has a tightly constrained set of root causes. Investigate them in the order shown.

1. Missing or Undersized Line Filter / Reactor

This is the most common root cause and matches the symptom described — non-repeatable, intermittent, on first enable after power-up. SINAMICS S120 ALM regulations require either:

• A line filter (e.g. 6SL3000-0BE21-6DA0) in front of an external line reactor, or
• An Active Interface Module (6SL3100-0BE21-6AB0) which integrates the line filter and reactor as a single unit.

Operating the ALM without either combination causes excessive line-side harmonics. The identification algorithm reads back distorted voltage and current waveforms, computes a negative or out-of-range impedance, and aborts with F06200. Because the harmonic content of the supply depends on what other loads are online at the moment of cold start, the fault appears intermittent — exactly as observed.

2. VSM Configuration Without Hardware

If p0221.0 = 1 (line identification via VSM) but no VSM is wired, the ALM waits for VSM telegrams that never arrive and times out. Verify:

On AIM-equipped systems, p0221 must equal 0 unless an external VSM is explicitly wired to the DRIVE-CLiQ port X202 of the ALM.

3. DC-Link Capacitor Module Influence

The Capacitor Module 6SL3100-1CE14-0AA0 adds 1.4 mF to the DC link. On a 16 kW ALM the standard DC link is ~110 µF of internal capacitance plus connected Motor Module capacitances (each booksize 18 A module ≈ 20 µF, 9 A ≈ 10 µF). The total is well below the ALM's pre-charge controller's stability limit and does not in itself trigger F06200. However, during the line identification step the ALM deliberately applies a low-frequency current pulse through the line-side reactors and measures the response. Excessive DC-link capacitance shifts the resonance of that pulse network and can cause the algorithm to time out. If F06200 appears only when the capacitor module is plugged in, set p3421 = 0 to disable the line identification (use this only when line parameters are known with high certainty and stable).

4. Supply-Side Anomalies

Measure at the AIM input terminals with a true RMS meter:

The line identification sequence samples the supply during a ~1 s window; sustained sags, surges, or switching of large upstream loads during that window produce a misidentification. This also explains why the fault is reported as not repeatable — successive cold starts may catch the supply at different points of the upstream load cycle.

5. DRIVE-CLiQ Topology or Firmware Mismatch

On the CX32-2 controller extension, the connected Motor Modules appear as SINAMICS Integrated objects. The CX32-2 and ALM must share compatible firmware. Verify with the SCOUT/TIA commissioning tool that the firmware versions are within one functional range (cross-check on the Siemens Industry Online Support compatibility matrix). A mixed-firmware line-up sometimes disables the line identification routine silently, surfacing as F06200.

Resolution Procedure

1. Power down and lock out. Verify zero potential at the line filter input. Discharge the DC link by waiting the printed time (minimum 5 min for a 16 kW ALM after removal of the 24 V supply).
2. Confirm filter presence and seating. The 6SL3000-0BE21-6DA0 top-hat filter must be plugged into the AIM or wired in series with the line input. The PE stud of the filter must be bonded to the cabinet PE bus with the shortest practical conductor.
3. Verify AIM wiring. L1, L2, L3 of the supply → filter input → AIM X1 line side → AIM X2 output to ALM X1. Verify that the ground stud on the AIM is bonded and that the DRIVE-CLiQ cable from AIM port X202 to the Control Unit is intact.
4. Re-check p0221. In SCOUT/TIA, navigate to Infeed → Configuration and confirm:

p0221 = 0  // line identification via ALM/AIM measurement
p0222 = 0  // VSM not assigned

5. Clear the fault and re-attempt identification. On the SIMOTION HMI or in SCOUT, issue an Acknowledge on the active faults. Then issue OFF1→OFF1 to retrigger line identification. The ALM will raise A06400 for the duration of the identification.
6. If F06200 persists, capture the line identification result via parameter r3415 (line model values). Record:
   • r3415[0] — identified line resistance (Ω per phase)
   • r3415[1] — identified line inductance (H per phase)
   • r3415[2] — identified capacitance (F, line-to-line)
   • r3415[3] — line frequency (Hz)
7. If r3415[0] or r3415[1] reads zero or negative, the supply was not connected at the moment of identification — re-check the line contactor upstream.
8. Save the parameters offline (RAM → ROM).

Parameter Reference

Line Identification Sequence Explained

Understanding what A06400 / F06200 actually represent makes the troubleshooting faster. The ALM executes the following state machine when p3410 = 0:

1. State 0 — Idle. ALM waits for the first ON command after power-up or after a factory reset.
2. State 1 — Pre-charge. Pre-charge contactor closes, DC link rises to rectified peak line voltage.
3. State 2 — Identification request (A06400 raised). ALM injects a defined low-frequency current pulse through the integrated reactors and measures the voltage response.
4. State 3 — Compute. From V/I sample pairs the firmware derives R and L of the supply.
5. State 4 — Validate. Computed R and L are compared against plausibility windows stored in the firmware.
6. State 5a — Pass. A06400 cleared, ALM transitions to RUN, gating enabled.
7. State 5b — Fail. F06200 raised with the most recent sample in r3415 for diagnostics.

A failure at State 4 — when the firmware rejects the computed values — is what produces the seemingly random intermittent behavior. The values were computed, but they fell outside the expected physical envelope because the supply impedance seen from the ALM was too low (filter or reactor missing) or too high (excessive upstream impedance).

Commissioning Best Practices

• Always populate the SINAMICS S120 line-up with the AIM or the line filter + reactor pair listed in the S120 Equipment Manual for that ALM rating. The 16 kW class explicitly requires either combination; see the SINAMICS S120 Equipment Manual for booksize drive units for the configuration table.
• Perform the first ON after power-up with the upstream distribution transformer loaded only by this drive line-up. Other large loads in the same switchboard can shift the measured impedance.
• After each download of project data, the ALM will re-identify the line. If the supply is stable and known, set p3421 = 0 only as a permanent override; otherwise leave p3421 = 1.
• Document r3415 in the commissioning report. A baseline record speeds up future root-cause work if F06200 ever recurs.

Verification

After applying the corrective steps, validate the system through this checklist:

1. Power-cycle the line-up. Confirm no faults present at the Control Unit's 7-segment display or in SCOUT/TIA's fault buffer.
2. Issue an OFF1 enable to the infeed. Observe A06400 for ~1 s, followed by Infeed RUN and the green READY LED on the ALM.
3. Confirm no Motor Module raises F07802 (Ready missing) or F08501 (PROFIdrive communication failure) as a knock-on effect.
4. Issue a small velocity setpoint to one of the connected motors and verify torque-producing current (r0077) and DC-link voltage (r0070) are within expected bounds.
5. Capture r3415 as the commissioned baseline and archive it with the project.

Related Faults and Information Messages

Field-Proven Caveats

• The fact that F06200 clears after a power-cycle on the source system is consistent with a borderline line condition. A single observation of clearance is not proof that the line filter is correctly sized; record r3415 over several cold starts and verify the values are consistent within ±10 %.
• If the cabinet contains additional EMC/RFI filters from a third-party supplier on the same line input, they may appear in series with the AIM filter and shift the identification. The S120 Equipment Manual specifies the only approved filter combinations per ALM class.
• The CX32-2 introduces its own DRIVE-CLiQ node; the ALM must be the last node in the DRIVE-CLiQ chain or placed according to the topology rules in the SIMOTION D4x5-2 Commissioning and Hardware Installation Manual. Mis-ordering does not cause F06200 directly but can corrupt the line identification by introducing telegraph delays on X202.
• Do not connect a brake chopper or external 24 V supply to the DC link while the line identification is in progress (A06400 visible). The identification assumes a defined load model.

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