Resolving SINA_POS F07452 Fault on SINAMICS S120 with 1PH7

Resolving SINA_POS F07452 Fault on SINAMICS S120 with 1PH7 Motor

A SIMOTICS M 1PH7137 asynchronous spindle motor controlled by a SINAMICS S120 (CU310 PN) through SINA_POS in TIA Portal V15 unexpectedly accelerates to p1082 (maximum speed) when ModPos = 3 and Velocity = 0, then drops out with F07452 (A) after a few seconds. This article documents the root cause, the diagnostic path through Starter V5.1, and the field-proven remediation sequence.

1. Affected Hardware and Software Stack

The 1PH7137 is a forced-air-cooled SIMOTICS M asynchronous motor designed for machine-tool main spindles. On SINAMICS S120 it is normally configured for vector control (p1300 = 20 / 21 / 22 / 23) and, when the application needs positioning, the basic positioner (EPOS) function module.

The CU310 PN documentation and the 1PH7 motor configuration guidelines are referenced in the SINAMICS S120 Knowledge Base article on slip and deceleration with Safety Integrated (FW 4.3+) and the Siemens Industry Mall configurator for the spindle family.

2. Why the Motor Ramps to p1082

The drive is following the velocity setpoint coming out of the extended setpoint channel instead of the EPOS position setpoint. In a SINAMICS S120 configuration where both the extended setpoint channel with ramp-function generator (RFG) and the basic positioner (EPOS) are activated, two competing setpoint sources exist:

1. EPOS computes a position profile that becomes a velocity pre-control for the speed controller.
2. The extended setpoint channel (main setpoint via p1070/p1001) drives the speed controller directly via the RFG.

When the SINA_POS telegram (111) is wired and the S7-1500 writes 0 to the velocity word, EPOS correctly commands 0. However, if the extended setpoint channel is still active and is fed by another source (main setpoint from a terminal, a fixed setpoint, or a residual value from the previous commissioning), it will inject a non-zero velocity that bypasses EPOS. Because p1082 is the absolute ceiling of the RFG output, a saturated setpoint will immediately push the motor to n_max.

Additionally, jog mode (Mode 7, jog 1/jog 2) does not prove this out: the jog velocity is taken from p1058/p1059 inside the drive, not from the telegram. If jog also runs the motor to p1082, the problem is not the SINA_POS data words but the drive setpoint path itself.

3. Why F07452 Is Raised

F07452 ("Drive: Following error") is the EPOS-side following-error monitor. It is configured by:

• p2542 – Position controller, position actual value smoothing
• p2543 – Position controller, pre-control factor (KV factor)
• p2544 – Following error, dynamic tolerance window
• p2545 – Following error, static tolerance window
• p2546 – Following error, time monitoring

When the extended setpoint channel forces the rotor to n_max with no encoder on the load side, the EPOS position controller sees a wildly diverging actual position. After p2546 ms, F07452 is raised and (with default alarm behavior A) the drive shuts down via the configured fault reaction.

This fault is a symptom, not the root cause. Fixing the extended setpoint channel typically eliminates F07452 immediately because the position controller is then given a proper setpoint to track.

4. Diagnostic Path in Starter

1. Open the Starter V5.1 project online to the CU310 PN.
2. Open the Function diagrams and navigate to:
   - Sheet 3010 (Setpoint channel, RFG)
   - Sheet 3630 (EPOS, position controller)
   - Sheet 3635 (Following error monitoring)
3. Use the Trace function to record the following signals:
   - r0062 – Speed setpoint after RFG
   - r0063 – Actual speed (encoderless)
   - r2550 – EPOS position setpoint
   - r2521 – EPOS actual position
   - r2533 – EPOS following error
   - r2050[0..15] – PZD receive words from telegram 111
4. Trigger the fault and examine what drives r0062 before the EPOS setpoint. The non-zero source at r0062 is the culprit.

If r0062 shows the saturated p1082 value while the EPOS path shows a velocity of 0, the diagnosis is confirmed: the extended setpoint channel is forcing the speed.

5. Remediation Sequence

5.1 Disable the extended setpoint channel for EPOS

Run the following steps in Starter (offline, then load to drive):

1. Open Drive → Commissioning → Configure DDS and select the configuration screen for the active drive data set.
2. Click Setpoint channel and uncheck "Extended setpoint channel with ramp-function generator" if your Starter wizard offers it. If not, set the relevant parameters manually:

3. Save RAM to ROM and power-cycle the CU310 PN so that p0971 takes effect.
4. Re-test: enable drive, set ModPos = 3, Velocity = 0, direction = positive. Motor must remain at standstill with active torque. r0062 should show ~0.

5.2 Confirm correct telegram and SINA_POS mode

SINA_POS uses telegram 111 (or 110 for older configurations) plus the 39-byte free telegram for the SINAMICS parameter channel. Verify in Starter:

SINA_POS mode mapping (TIA Portal library, current versions):

5.3 Reset and partial recommission

If the configuration is heavily contaminated, perform a parameter reset and re-commission only the minimum necessary:

1. Set p0970 = 1 to reset drive parameters to factory defaults; wait for the drive to come back.
2. In Starter, restart the configuration wizard. Choose:
   - Vector control (p1300 = 21) without sensor
   - Speed controller auto-tuning: p1960 = 1 with standstill verification
   - Activate EPOS (Position control) only – do not activate the extended setpoint channel.
3. Complete the homing configuration: p2596 referencing mode, p2599 homing start.
4. Set the telegram to 111 and download to the drive.

5.4 SINA_SPEED alternative

If the application only needs speed control (no real positioning), switch from SINA_POS to SINA_SPEED with telegram 1. This eliminates EPOS entirely:

1. In Starter, set p0922 = 1 (Standard telegram 1).
2. In TIA Portal, replace SINA_POS with SINA_SPEED from the same library.
3. Use telegram 1 control word (r2050[0]) – bits 0/1/2/3/6 govern ON/OFF1, OFF2, OFF3, enable, setpoint enable.

This is the cleanest fallback for 1PH7 axes that act as pure spindles without positioning.

6. Verification Procedure

1. With drive off-line, observe r2521 (actual position) and r2550 (setpoint position) in Starter expert list – both should match.
2. Enable the drive via SINA_POS. r0062 should remain 0 when Velocity = 0.
3. Set ModPos = 3, Velocity = 100 RPM, direction positive. Motor should accelerate to a slow positive speed, not p1082.
4. Run for at least 30 s. Confirm no F07452.
5. Stop via SINA_POS cancel-task mechanism. r2521 should remain stable.
6. Switch to ModPos = 2, command an absolute move. Position controller must settle within p2544 without fault.

7. Parameter Quick Reference

8. Trace and Signal Flow Diagram

The expected signal flow when EPOS is correctly configured with telegram 111 and the extended setpoint channel is disabled:

The dashed line from the EXT RFG block represents the disabled path; the dashed feedback line shows the F07452 origin.

9. Troubleshooting Matrix

10. Field-Proven Notes

• The same project working on another axis is not a guarantee; commissioning differences in the DDS selection or the activation of "extended setpoint channel" during the wizard are the typical divergence points.
• If the user lacks access to the Starter trace tool, deploy SINA_SPEED with telegram 1 first; the speed loop is more forgiving during setup.
• Never adjust p1082 to "fix" the symptom. p1082 is the speed ceiling of the RFG; lowering it will not stop the runaway if the extended setpoint channel remains active.
• For asynchronous (induction) main-spindle motors such as 1PH7137, the slip behavior under Safety Integrated SS1/SLS without encoder is documented in the Siemens KB article referenced above; verify SS1 timing if Safety is in scope.
• When the application actually needs precise angular control of an asynchronous motor, advanced control methods such as fuzzy-assisted vector control (see the IEEE article on accurate control of asynchronous motors) are research-stage options and not part of the standard S120 firmware.

11. FAQ