Resolving SINAMICS G130 Topology Alarm 1416 with SMC30 Encoder

Problem Summary: Alarm 1416 on a SINAMICS G130 with an SMC30 Encoder Module

A SINAMICS G130 chassis drive (article-number family 6SL3310-1GE..-.AA3 / .BA3) configured for closed-loop speed control with encoder evaluation raises warning A1416 - "Topology: Comparison additional component in actual topology" - whenever the physical DRIVE-CLiQ topology detected at power-up does not match the offline project stored on the Control Unit's CompactFlash card. On a drive object configured for an external Sensor Module Cabinet-Mounted (SMC30, article number 6SL3055-0AA00-5CA2 or the safety-extended variant 6SL3055-0AA00-5CA3), the most common trigger for this warning is an offline project in which no SMC30 was inserted at the corresponding DRIVE-CLiQ port of the CU320-2 Control Unit (article numbers 6SL3040-1MA01-0AA0 for PROFIBUS and 6SL3040-1MB01-0AA0 for PROFINET).

The warning appears as a yellow ALARM LED indication on the AOP30 operator panel and as text in the STARTER / Startdrive diagnostic buffer, but does NOT latch the drive to fault state. The drive remains runnable, motor identification completes, and basic V/Hz or sensorless vector operation is possible. Encoder-based control loops (n-set speed actual from r0061, position actual from r0482) operate with default or fallback parameters until the topology is reconciled. Until then, drive-side encoder errors and slip conditions cannot be diagnosed correctly because the encoder parameters p0400 through p0431 on the affected drive object remain at their initial values. Refer to the SINAMICS G130 Operating Instructions for the full DRIVE-CLiQ topology rules.

Decoding Alarm 1416 via r2124 and r2125

SINAMICS alarms are produced as structured values rather than free text. The active alarm text shown on the AOP30 is built from the alarm number (1416) plus the alarm value stored in parameter r2124[0...63] on the alarm-producing drive object. For A1416 the r2124 value encodes the component class, DRIVE-CLiQ port index, and component number of the additional component found in the actual topology. The typical decode for the value 36177099 decimal reported on the affected drive is summarised in the table below.

The corresponding status word in r2125[0...63] shows bit 0 (alarm active) and bit 7 (alarm still present) set, with bit 1 (alarm no longer present) cleared. This combination is what produces the yellow alarm rather than a fault: A1416 is a warning, not a fault, so the drive object's state machine allows continued operation. On a separately-armed fault class (F1415) the same topology mismatch would latch a fault and pulse-inhibit the drive.

If a different alarm value is reported - for example one in which r2124 encodes a different DRIVE-CLiQ port index or component class - it points to a different missing component. The decoder above is specific to a configuration of an SMC30 on X202 of a CU320-2 PN with one active SMC slot. The exact DRIVE-CLiQ port index on which the encoder module is found is also recorded in r9906 (compare topology: target) and r9907 (compare topology: actual) once the topology comparison has been performed.

Root-Cause Matrix for A1416

A1416 can be produced by several distinct root causes that share the same alarm number but differ in the value stored in r2124. The five cases most frequently encountered on SINAMICS G130 installations are listed below, together with their distinguishing fingerprint.

The reported case (alarm 1416, alarm value 36177099, SMC30 not visible in the offline component depot of STARTER) is consistent with root-cause #1 with a specific twist: the SMC30 was selected during the configuration wizard but never actually instantiated in the offline project. The encoder dropdown in the wizard generates only the parameter list, not the topology node; a separate "Insert encoder module" action is required in the topology editor.

SINAMICS G130 Topology Architecture and SMC30 Hardware

The SINAMICS G130 chassis drive is built around three mandatory physical components: a Control Unit (CU320-2 DP or CU320-2 PN), a Line Module (Active Line Module ALM or Basic Line Module BLM), and a Motor Module. Optional components - Terminal Modules, Sensor Modules (SMC10/20/30/40), Hub Modules (DMC20), and the AOP30 operator panel - connect to the Control Unit via DRIVE-CLiQ, a proprietary Siemens serial real-time protocol that carries encoder, torque, and inter-DO communication traffic.

The CU320-2 has four physical DRIVE-CLiQ ports (X100, X101, X102, X103 on the basic variant) plus two ports on a plug-in CBE20 communication board (X1200 / X1201 for PROFINET). On the extended variant the additional ports X200 through X203 become available. The conventional topology for a single-axis G130 with encoder feedback is:

• Port X100: Power Module chain (Line Module + Motor Module, fixed topology)
• Port X101: AOP30 operator panel (optional)
• Port X102: Terminal Module TM31 (optional I/O)
• Port X103 or X201/X202: SMC30 (or SMC20) for encoder feedback

If the system uses a CU320-2 PN with the second DRIVE-CLiQ board fitted, the additional ports X200, X201, X202, X203 become available, and the SMC30 is normally placed on X201 or X202 - matching the r2124 port index of 2 (X202) decoded above. Whatever the port, the topology comparison performed at every power-up looks at the offline p9905 descriptor and compares it against the actual DRIVE-CLiQ enumeration; a mismatch is what raises A1416.

The SMC30 is the SINAMICS Sensor Module for cabinet mounting that supports HTL, TTL, and SSI encoders at voltages of 5 V and 24 V. It is the encoder evaluation board used whenever the encoder is mounted on the motor side and connected to the cabinet via a separate cable - for example on retrofit applications where the existing encoder on the motor cannot be wired to a Sensor Module Integrated (SMI) on the motor.

The SMC30 occupies one DRIVE-CLiQ node. It has three sub-slots for encoder channels (X521 for HTL/TTL incremental, X531 for SSI absolute, plus a third for SSI secondary if safety is fitted). On a single-channel speed-control application only X521 is used, so the project can leave p014 at 1 and configure only X521. The "two options" the configuration wizard presents are normally the two encoder interface families that the SMC30 supports: HTL/TTL incremental on connector X521 and SSI absolute on connector X531. Selecting the appropriate option ensures that parameters p0400 through p0431 on the affected drive object receive a non-default encoder configuration.

Commissioning Workflow in STARTER

The configuration wizard in STARTER walks through control structure (V/f, sensorless vector, vector with encoder) and - for the encoder case - presents the encoder interface selection. The wizard does NOT instantiate the SMC30 as a topology node. Inserting the SMC30 into the offline project is a separate manual step in the topology editor. The complete offline commissioning sequence is:

1. Open STARTER (V5.4 SP3 or later) or Startdrive in TIA Portal V16+.
2. Open the project for the affected G130 and navigate to the drive object (typically DO 2 = "Drive_1" / SERVO or VECTOR, depending on the control mode selected).
3. Run the configuration wizard. For encoder-based speed control, choose "Speed control with encoder".
4. In the encoder subsystem page of the wizard, select "SMC30" as the sensor module and "Incremental HTL/TTL" (or SSI if the encoder is absolute).
5. Complete the wizard; this writes p0400...p0431 on the drive object with the correct defaults for the selected encoder family.
6. Click "Finish" - the wizard closes and returns to the project tree.
7. In the project tree, locate the CU320-2 entry (top-level), right-click the DRIVE-CLiQ port where the SMC30 is physically connected (X202 in the reported case), and select "Insert new component > Sensor Module > SMC30 (6SL3055-0AA00-5CA2)".
8. The topology editor now shows the SMC30 as a child node of the CU320-2. Confirm the article number matches the physical SMC30 (read it from the nameplate of the real module).
9. Save the project (Ctrl+S) and download to the drive ("Download to target device").
10. After the download, STARTER prompts to copy RAM to ROM. Click "Yes" to write the new topology to the CompactFlash card.

If step 7 is skipped, the wizard populates the encoder parameters but the SMC30 never appears in the offline topology. At next power-up the drive enumerates the physical SMC30 over DRIVE-CLiQ and produces A1416 because no matching slot exists in the saved project. Refer to the SINAMICS S120 / G130 List Manual for the complete parameter reference.

Encoder and Sensor Module Parameters

The encoder parameter block lives on the drive object, not on the SMC30. The SMC30 only carries the interface firmware and the digital signal conditioning; all encoder semantic parameters are written to p04xx on the DO. The most commonly adjusted parameters for an encoder evaluation path are:

All these parameters are written into the project on the drive object via the configuration wizard. They are NOT sufficient by themselves to clear A1416; the topology node must also exist. The reason is that the encoder parameters bind a logical encoder ID (p0400...p0431) to a sensor module that the topology editor must have inserted as a DRIVE-CLiQ child of the CU320-2.

When the topology is correctly inserted, STARTER creates a second sub-DO under the CU320-2 for the SMC30. The parameters most commonly inspected on that sub-DO are:

If A1416 is cleared but the drive then produces F31117 or A33417 (encoder signal failure), inspect the p34xx block on the SMC30 sub-DO. The most frequent misconfiguration is p3402 set to 5 V while the encoder cable delivers 24 V HTL - the SMC30 will not detect edges and the encoder status word reports no signal.

Accepting the Actual Topology: p9905 to p9909

If the offline project cannot be edited (for example on a black-box retrofit where the original STARTER source has been lost), SINAMICS provides a one-step mechanism to make the offline topology match the actual topology: the "Accept actual topology" function. It is implemented as a parameter write to p9905 with a specific handshake pattern, and propagated through p9906, p9907, p9908, p9909:

The accepted procedure in STARTER is to call "Topology > Accept actual topology" from the right-click context menu on the CU320-2 node. STARTER then internally sets p9909 = 1, waits for the drive to reboot, and confirms the new topology is saved. After the reboot the value of r9908 should be 0 (no differences) and A1416 should be cleared from the diagnostic buffer. The CompactFlash is updated as part of the same handshake; no separate "copy RAM to ROM" is needed.

If the drive is locked out of STARTER access, the same operation can be performed manually via the AOP30: navigate to p9909, set to 1, confirm with OK, and accept the resulting "Topology changes - reboot?" prompt. The drive will power down and restart with the actual topology loaded.

Output Filter Check After Power Module Replacement

The supplementary conditions document shipped with SINAMICS Startdrive V17 contains a related topology-relevant warning: after replacing a power module, the output filter parameters p230, p231, p232, p233, and p234 may revert to factory defaults and must be re-checked. While this is a different alarm class from A1416, the principle is the same: a topology or component change can propagate parameter defaults that look like drive errors but are really configuration regressions. After accepting the actual topology and clearing A1416, take a moment to verify p230...p234 against the design specification - particularly on drives with sine-wave filters or du/dt filters. The full list of V17 caveats is documented in the SINAMICS Startdrive V17 Supplementary Conditions.

Verification Procedure After the Fix

Once the topology has been reconciled and the project downloaded, the verification checklist is:

1. Power-cycle the drive. The CU320-2 performs a fresh DRIVE-CLiQ enumeration and a topology comparison. The diagnostic buffer should contain no A1416 entries after this reboot.
2. Inspect r9908 on the CU320-2. The value should be 0 (no topology differences). A non-zero bitmask indicates a residual mismatch.
3. Inspect r0450[0] on the drive object. Bit 0 (initialised) should be set; bit 15 (encoder fault) should be cleared.
4. Verify the encoder pulses in r0061 move in the correct direction and at the correct speed when the motor is turned manually or jogged. A sign reversal can be compensated by p0410[0].bit 14 (invert encoder signal).
5. Run the motor identification routine p1910 = 1 (motor data identification, standstill) and, if required, p1960 = 1 (speed controller optimisation). These populate p1441/p1470 and other control parameters using the real encoder feedback.
6. Save the parameter set with p0977 = 1 (RAM to ROM). The CompactFlash now holds the corrected topology and encoder configuration.

Related Alarms and Diagnostic Matrix

SINAMICS produces a family of topology-related alarms and faults. Knowing which alarm maps to which defect reduces mean time to repair on the bench. The matrix below covers the cases most often confused with A1416.

Edge Case: Misleading Topology Messages in Startdrive V17

The SINAMICS Startdrive V17 Supplementary Conditions lists a class of misleading warning messages that appear under specific conditions during online topology comparison. The most relevant ones for the user's scenario are:

• When the project was created in an older STARTER version (pre-V5.4) and opened in Startdrive V17, A1416 may fire spuriously at the first download because the offline topology descriptor uses an old format that Startdrive V17 does not fully recognise. The fix is to open the project in STARTER V5.4 first, save it once to refresh the descriptor, then re-open in Startdrive V17.
• When the CU320-2 firmware is V5.2 SP3 or older and the SMC30 firmware is more recent, A1416 may fire even though the topology is correct because the older CU firmware does not fully decode the newer SMC electronic nameplate. The fix is to update the CU320-2 firmware to V5.2 SP3 HF3 or later via p7820/p7821.
• When the project is run through a TIA Portal V17 project migration, the topology descriptor may lose the SMC30 child node. The fix is to re-insert the SMC30 in the TIA Portal topology editor and re-download.

If A1416 reappears within minutes of being cleared, check whether the diagnostic buffer contains a preceding F1415 (component comparison failed) - this points to a firmware-version mismatch rather than a missing-topology-node issue.

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