Resolving S120 F07220 Fault with S7-1200 SINA_POS FB284

1. Problem Overview

When integrating a SIMATIC S7-1200 CPU with a SINAMICS S120 drive via PROFINET and the SINA_POS (FB284) library block, the most common commissioning failure produces three coupled symptoms:

1. The SINAMICS S120 reports F07220 in its fault buffer.
2. The SINA_POS instance reports Error = 5 (drive fault), then Error = 6 (switching on inhibited), and finally FaultAct = 1C34 on each new attempt.
3. Acknowledging with FN on the S120 only clears the drive-side fault momentarily; the next SINA_POS execution re-triggers it within one second.

The combination is almost always traceable to one of three configuration defects: a missing PROFINET partner-port assignment, an unassigned or incorrect telegram-111 hardware identifier (HWID), or a missing control-word enable in STW1. This reference walks through each layer, in the order that must be verified.

2. Required Hardware and Software Stack

The PROFINET telegram 111 is a Siemens-specific, position-control oriented standard telegram containing two 16-bit control words (STW1, STW2), two 16-bit status words (ZSW1, ZSW2), a 32-bit speed setpoint, a 32-bit actual speed, and a 32-bit position setpoint/actual pair. It is the default selection when using the SINA_POS library because the block expects that exact PZD layout.

3. F07220 — Fault Code Analysis

F07220 on the SINAMICS S120 family belongs to the controller-level fault group. In the S120/S150 List Manual (LH1), it indicates a configuration or enable-logic violation within the control sequence and is most often triggered when:

• The drive receives a closed-loop enable (p0840, OFF1) without the corresponding pulse enable (p0850, drive enable / inverter enable).
• The PROFINET partner port on the S120 side is configured but the S7-1200 port has not been assigned as the IO controller.
• Smart Line Module (SLM) or Active Line Module (ALM) pre-charge and DC link readiness is incomplete when the drive enable arrives.
• Word STW1 bits 0–3 are toggled in an order that violates the S120 state machine (e.g., ON/OFF1 = 1 before the drive has reached "Ready to switch on").

The fault is recoverable (Acknowledgeable), which matches the behavior reported: pressing FN on the S120 clears the buffer, but the fault re-appears on the next SINA_POS pulse because the underlying enable sequence is still wrong.

4. SINA_POS (FB284) Error State Machine

The Error and FaultAct outputs of SINA_POS form an internal state machine. The sequence reported in the source — Error 5, then Error 6, then Error 5 with FaultAct = 1C34 hex — maps as follows:

The FaultAct output carries the decoded fault/cause word from the SINA_POS internal buffer. 0x1C34 decomposes as:

• High byte 0x1C = drive is in "Switching on inhibited" because the OFF1/OFF2 chain is open.
• Low byte 0x34 = the SINA_POS has detected that ZSW1.0 / ZSW1.1 / ZSW1.2 do not match the requested enable sequence.

This pattern is the SINA_POS equivalent of "the drive was commanded to run but never reached the run state", and it is the most common response when the partner port on one side of the PROFINET IO is missing.

5. Root Cause #1 — Missing PROFINET Partner Port

The user confirmed that the original error 5 / error 6 cycle was resolved by defining the partner port on both the CPU and the S120 in TIA Portal. This is the single most common first-time integration mistake on S7-1200 to S120 links.

CPU side (IO Controller)

1. In the TIA Portal device view, open the S7-1200 CPU Properties → PROFINET interface.
2. Assign the PROFINET device name of the S120 Control Unit (the name configured in STARTER / Startdrive) as the IO device in the topology editor.
3. In Topology view, right-click the S120 port → Assign partner port → select the matching port on the CPU (port 1 in this case).

Drive side (IO Device)

1. In the S120 STARTER project, the Control Unit's PROFINET interface must have the device name assigned exactly as set in the TIA Portal project (case-sensitive, including hyphens).
2. If using an SLM/ALM in the same rack, the Line Module's PROFINET interface must also be assigned a partner port, even if no cyclic data is exchanged with it.

6. Root Cause #2 — Telegram 111 and HWID 279

The PROFINET slot carrying telegram 111 on the S120 is what SINA_POS writes STW/ZSW through. If the HWID in the FB284 call does not match the slot assigned by TIA Portal, SINA_POS reports drive faults even though the drive is healthy.

Confirming the HWID

1. Open the device view in TIA Portal → S120 Control Unit → Properties → PROFINET IO → Module parameters.
2. Locate slot 1 (or whichever slot carries telegram 111). The Hardware identifier field shows the HWID — 279 in the documented case.
3. Pass this value to the FB284 inputs LaddrSP (setpoint) and LaddrAV (actual value). Both inputs must reference the same HWID for telegram 111 because send and receive PDUs share the slot.

// SINA_POS FB284 call wiring (illustrative)
#SINA_POS(LaddrSP  := 279,   // HWID for telegram 111 - setpoint
          LaddrAV  := 279,   // HWID for telegram 111 - actual value
          ModePos  := 1,     // 1 = relative positioning (test)
          Enable   := TRUE,  // FB284 enable
          Execute  := "Tag_Execute_Toggle",
          RejTrvTsk:= TRUE,
          IntMStop := TRUE,
          Pos     := 1,
          Neg     := FALSE,
          Jog1    := FALSE,
          Jog2    := FALSE,
          FlyRef  := FALSE,
          AckFault:= "Tag_Ack",
          Velocity:= 1000.0,
          OverVAD := 100.0);

7. Root Cause #3 — STW1 Enable Signal

Even when the PROFINET link and telegram 111 are correct, the drive will reject any positioning command if STW1 does not carry the expected enable pattern. The S120 expects the following sequence, applied in order:

SINA_POS internally drives these bits via STW1 when the Enable input is set; however, the block also depends on the application setting STW1.Bit15 if the configured drive profile uses it as "External pulse enable" or "Slave-to-slave enable". A common configuration in STARTER is to map STW1 bit 15 to the parameter p0850 via the bit-3-to-p0850 linkage; if the bit is not set in the SINA_POS internal image, the drive never reaches "Operation enabled", and F07220 is logged the next time the drive tries to close the pulse enable.

Diagnostic path

1. In TIA Portal, place a watch table on the SINA_POS instance DB and inspect SinaPos.sxSendBuf.sxSTW1 at runtime.
2. Confirm bits 0, 1, 2, 3 are all 1 before Execute is pulsed.
3. If bit 3 is 0 even after Enable = TRUE, the drive has not signalled readiness in ZSW1 — this is typically a Line Module (SLM/ALM) readiness issue.

8. Step-by-Step Commissioning Procedure

The following sequence, executed in order, resolves the F07220 / FaultAct 1C34 combination in the vast majority of S7-1200 + S120 integrations.

1. Verify CPU firmware / library compatibility. CPU 1214C FW V1.0 only supports the legacy SINA_POS block (FB284 with V1.x to V2.x internals). Upgrade the CPU firmware or downgrade the SINA_POS library version if TIA Portal installed a newer block.
2. Assign PROFINET partner port on both sides. Topology view in TIA Portal + PROFINET device name in STARTER / Startdrive must match.
3. Configure telegram 111 with HWID 279 (or whatever value your slot configuration yields). Pass it to LaddrSP and LaddrAV.
4. Validate enable logic in STARTER:
   • p0840 (OFF1) must be sourced from r889.0 (PROFINET STW1 bit 0).
   • p0852 (OFF3) must be sourced from r889.2 (STW1 bit 2 inverted).
   • p0850 (pulse enable) must be sourced from r889.3 (STW1 bit 3) AND the inverter enable bit configured in the expert list.
5. Check the Line Module: If using a Smart Line Module, confirm r863.0 (Line Module ready) is fed into the drive enable chain. The drive will refuse to close the pulse enable until the DC link is charged.
6. Place SINA_POS in test mode first. Use ModePos = 0 (speed control) with Execute as a toggle bit to confirm that the basic enable sequence closes. If Error = 0 and the motor responds, the PROFINET and enable wiring is correct.
7. Move to relative positioning (ModePos = 1), then absolute (ModePos = 2), then homing (ModePos = 4). Only progress when the previous mode is stable.
8. Monitor FaultAct continuously in a watch table. Any non-zero FaultAct points to the block's internal cause buffer — decode via the SINA_POS documentation table.

9. Speed Control Test Mode (Recommended First Validation)

The discussion recommended the following wiring for the initial test before any position-mode operation. This is the recommended pattern because it bypasses encoder and reference-point dependencies and verifies only the enable + PROFINET chain:

If the drive accelerates to the requested speed under this wiring without raising F07220, the PROFINET partner port, telegram HWID, and STW1 enable chain are all confirmed correct. Subsequent steps can then build position control on top of a known-good foundation.

10. Position Modes

The documented case confirms ModePos = 4 must run before ModePos = 2. Attempting absolute positioning without a successful reference will produce a ZSW1 "referenced" bit of 0, which SINA_POS interprets as a fault and re-arms F07220 on the next cycle.

11. Fault / Symptom Reference Matrix

12. Verification Checklist After Repair

1. S120 fault buffer is empty after a 60-second idle period.
2. SINA_POS Error = 0 and FaultAct = 0 for at least one minute in speed control mode.
3. The drive accelerates, holds, and decelerates without raising F07220.
4. Relative positioning (ModePos = 1) completes with Done = TRUE.
5. Homing (ModePos = 4) sets ZSW1.13 to 1 and writes a non-zero value to r2521.
6. Absolute positioning (ModePos = 2) executes to the requested setpoint and stops within tolerance.