SINAMICS S110 Switch-On Disable Resolving F31131 and F7453 Faults

Troubleshooting SINAMICS S110 "Switch-On Disable" and Encoder Faults F31131 / F7453 During STARTER Commissioning

The SINAMICS S110 is a single-axis servo converter in the SINAMICS family, designed primarily for positioning tasks with synchronous servomotors and asynchronous induction motors. When commissioning a new S110 with the STARTER commissioning tool (SINAMICS Startdrive or SCOUT equivalents depending on firmware generation), the most common first-start blocker is the message "The switch-on disable of the drive is active" when the green start button in the control panel is pressed. This article documents the precise diagnostic and corrective steps for that condition, the follow-on fault F31131 ("Deviation, position incremental/absolute too large") and the related LR fault F07453 ("LR position actual value preprocessing error"), including parameter p10 (drive state), p210 (line supply voltage), control priority handling, encoder wiring checks, and safety function handling.

1. Problem Description and Symptoms

During the first STARTER-driven commissioning of a SINAMICS S110 the user observes one or more of the following:

• The green start button in the STARTER control panel does not energize the drive.
• The status line reports "The switch-on disable of the drive is active".
• Parameter r0002 shows the drive is parked in state (0) Ready / Switch-on inhibit (or displays r899 bits that indicate OFF1/OFF2 inhibit, depending on firmware).
• After a brief successful jog, the drive faults out and the diagnostic buffer lists:
  • F31131 – "Deviation, position incremental/absolute too large" (encoder value mismatch).
  • F07453 – "LR position actual value preprocessing error" (position actual value conditioning on the Local/Remote or LR channel).
• Parameter p0010 is at =0 "Ready" (commissioning mode exited) but control priority has not been granted to STARTER.

2. SINAMICS S110 Drive Family Background

The SINAMICS S110 (catalog entry in the Siemens Industry Mall) is positioned between the basic SINAMICS V-class inverters and the multi-axis SINAMICS S120 platform. It accepts both synchronous servomotors (1FK7, 1FT7, 1FK2, etc.) and asynchronous induction motors, but unlike the S120 it does not natively support direct drives such as linear or torque motors. The reference manual is the SINAMICS S110 Equipment Manual (PDF).

Firmware versioning on the S110 historically uses the 4.x branch (CU305 PN control unit). STARTER versions 4.x and 5.x are the typical commissioning tools; SINAMICS Startdrive in TIA Portal V14+ can also target the S110 with the appropriate GSD/SINAMICS support package.

3. Root Cause Analysis

The "switch-on disable" condition is not a single fault – it is a state in which one or more of the S110 internal enable signals are missing. The four canonical enable paths on a SINAMICS drive are:

1. OFF1 enable (terminal / PROFINET control word bit 0)
2. OFF2 enable (control word bit 1; sources include safe standstill if a Safety Integrated function is configured)
3. OFF3 enable (control word bit 2)
4. Infeed / line contactor enable (depends on line configuration; for a basic S110 without Active Line Module this is internally tied)

For an S110 connected to a stand-alone line supply (no separate line filter module), the most common reasons the enable chain is incomplete on first start are:

3.1 Why F31131 and F07453 Follow a Brief Jog

When you press the green start button in the STARTER control panel after granting control priority, the drive usually does begin to energize for a brief moment – enough to pulse the motor a fraction of a turn. The encoder system returns a position value, but the absolute/incremental discrepancy filter detects an inconsistent result and raises F31131. F31131 in the S110 lists means: "Deviation between incremental and absolute position too large." This is the position-monitoring channel flagging that either:

• The encoder is wired with swapped signals (A/A̅ or B/B̅).
• The SSI absolute track and the sin/cos incremental track are not aligned (typical when the motor has a zero-mark offset that was not entered).
• The encoder was configured for a different motor during offline configuration.
• The encoder cable shield is not terminated correctly and noise is corrupting the position value.

F07453 ("LR position actual value preprocessing error") is raised by the position controller (Local/Remote or LR namespace in STARTER parameter view) when its input – the position actual value from the encoder system – is invalid because of F31131 or a related encoder fault. Clearing F31131 typically clears F07453 automatically on the next ramp-up; if F07453 persists after F31131 is cleared, the position-controller configuration itself is at fault.

4. Preconditions Before Clearing the Faults

Before re-attempting the start sequence, confirm the following preconditions:

1. The motor connected to the S110 is identified and the drive has been configured either by automatic configuration (for DRIVE-CLiQ motors, where the electronic nameplate is read over the drive-cliq cable) or by a manual offline commissioning in which you entered the motor data and encoder data.
2. The line voltage at the S110's line input terminals matches parameter p210 (line supply voltage). Common values are 380 V, 400 V, 480 V. Setting this incorrectly does not block the first enable but will produce nuisance faults during motion.
3. The encoder cable shield is clamped to the sub-D connector backshell on both ends.
4. Any Safety Integrated function (STO, SS1, SBC, SLS) has been explicitly configured to disabled if you are not wiring safety on the first start.

5. Step-by-Step Resolution

Step 1 – Verify Drive State via p0010 / r0002

In the STARTER expert list, navigate to parameter p0010 and confirm it is at =0 "Ready". Then check r0002 (drive operating display). A value of (0) "Ready / Switch-on disable" means STARTER has acknowledged the drive but enable signals are still missing. A value of (1) "Ready" is what you need before the green button will start the motor.

Step 2 – Grant Control Priority to STARTER

The most common reason the green start button fails on the first attempt is that the master control / control priority dialog was dismissed. Proceed as follows:

1. Click on the drive in the STARTER project navigator.
2. Open Control Panel (right-click the drive > Control Panel > Activate).
3. When the dialog "Do you want to take control priority?" appears, click Accept. Some STARTER versions require clicking the green "Take Control Priority" icon on the toolbar before the green start button becomes effective.
4. Confirm that the status bar shows "STARTER has control priority".

Alternatively, control the drive from the BOP (Basic Operator Panel) if one is mounted on the front of the S110. The BOP does not depend on STARTER control priority and is useful to isolate whether the issue is with STARTER's handshaking or with the drive's enable chain itself. On the BOP:

• Press P to access parameter view.
• Use the arrow keys to navigate to p0010; press P again.
• Confirm p0010 = 0; press P to save.
• Press the green I button to enable the drive, then the green "start" arrow.

Step 3 – Disable Safety Integrated Temporarily

Safety Integrated on the S110 is configured via parameters in the r97xx and p96xx/p98xx namespaces. If the drive is not wired for safety but STARTER's offline commissioning preset has STO enabled, the drive will sit in switch-on disable waiting for STO release. To disable on first start:

1. In STARTER, navigate to Drive > Functions > Safety Integrated.
2. Set the safety function selection to Basic Safety (STO via terminal) or without selection, depending on STARTER version.
3. If using extended safety, set p9601.0 = 0 and run the safety commissioning wizard to reset the CRC.
4. Save the project to the drive.

Step 4 – Confirm Control Word and Status Word

With STARTER connected, monitor r0054 (control word 1, from STARTER) and r0052 (status word 1, from drive). The status word bit pattern during correct operation should show:

• r0052.0 (Ready to switch on) = 1
• r0052.1 (Ready) = 1
• r0052.2 (Operation enabled) = 1 once enabled

If r0052.0 = 1 but r0052.1 = 0, look at the missing enable bits in the status word or in r899 (status word 2 / fault word). A typical pattern on S110 with Safety Integrated still active is r0052.1 = 0 with r9772.x indicating STO active.

Step 5 – Resolve the Encoder Fault F31131

If pressing the green button initially seems to work (motor jogs a fraction of a turn) but then faults with F31131, treat this as an encoder wiring or configuration issue. The encoder system on the S110 can be of three types: resolver, incremental sin/cos, or absolute SSI sin/cos (EnDat 2.1/2.2 also supported).

For an induction motor without DRIVE-CLiQ commissioned offline, you need to enter the encoder parameters manually. The relevant parameters are:

Procedure for clearing F31131 on a non-DRIVE-CLiQ induction motor:

1. Power off the S110 and lock out the line contactor.
2. Inspect the encoder cable for proper shield bonding at both the motor end and the drive end. The shield must contact the metal backshell of the sub-D connector.
3. Verify signal pairing on the encoder connector:
   • Pin 1 = A+, Pin 2 = A-, Pin 3 = B+, Pin 4 = B-, Pin 5 = R+, Pin 6 = R-
   • For SSI: Pin 7 = DATA+, Pin 8 = DATA-, Pin 9 = CLK+, Pin 10 = CLK-
4. Power on and connect STARTER. Read r0047 (encoder identification) and r0461 to see if the drive recognizes the connected encoder.
5. Open Configuration > Encoder in the STARTER drive navigator and click Encoder data identification. The drive will perform a small motion and identify the encoder parameters automatically, including the zero-mark offset.
6. Save the result back to the offline project with Copy RAM to ROM.

Step 6 – Clear F07453 if It Persists

If F07453 remains after F31131 is cleared, the position actual value preprocessing on the LR (Local/Remote) channel is misconfigured. Inspect:

• p2502 – Encoder assignment for position actual value
• p2503 – Actual value smoothing time constant
• p2530 – Position setpoint filter

Ensure the encoder selected at p2502 matches the encoder actually wired to the S110. Then clear faults with the Acknowledge button (the yellow exclamation icon) in STARTER or by setting p3981 = 1 followed by a power cycle.

6. Parameter Reference Table

7. Fault Code Quick Reference

8. Verification Steps

After applying the corrective steps, run the following verification sequence:

1. In STARTER, click Connect to target system and verify online.
2. Read r0002: it should show (1) "Ready" before any start command.
3. Open the STARTER Control Panel and click Take control priority > Accept.
4. Click the green start button. r0002 should transition to (4) "Operation enabled".
5. Use the jog buttons in the Control Panel to step the motor slowly in both directions.
6. Monitor r0021 (actual speed), r0024 (output frequency), and r0026 (DC link voltage). All should remain stable.
7. Confirm the diagnostic buffer is empty (no F31131, no F07453).
8. Stop the drive with the red stop button and then with OFF1; the drive should return to state (1) "Ready".

9. Preventive Commissioning Checklist

To avoid the switch-on disable and F31131/F07453 combination on future S110 installations, adopt the following commissioning checklist:

• Always run STARTER Configuration > Automatic configuration for DRIVE-CLiQ motors before any manual parameter changes.
• For non-DRIVE-CLiQ induction motors, complete the manual commissioning wizard in full and do not skip the encoder section.
• Always click Take control priority explicitly in the Control Panel toolbar; do not rely on the dialog default.
• Run the Safety Integrated commissioning wizard before the first motion attempt and document the configured safety state.
• Verify p210 matches the measured line voltage and confirm with a multimeter before energizing.
• After every successful test motion, perform Copy RAM to ROM so the changes survive a power cycle.

10. Escalation Path

If after applying the above the drive still faults with F31131 on first motion, the next escalation is the Siemens Application Support hotline. Have the following ready:

• STARTER project file (.zap) or trace file of the fault
• Diagnostic buffer dump (text export)
• Line voltage measurement at the S110 input
• Encoder cable part number and shield termination details
• S110 firmware version (read at r0018)

Siemens Application Support for SINAMICS is reachable through the regional support organization listed in the S110 Equipment Manual front matter, or through the global Industry Online Support portal.

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