What causes Siemens SINUMERIK alarm 16746?

Part program contains an illegal or unsupported command for the current machine configuration. Channel or axis configuration does not support the programmed function. Required machine option not enabled for the commanded function. Axis assignment or transformation configuration error. Program execution sequence error.

How do I fix Siemens SINUMERIK alarm 16746?

1. Identify the program block that triggered the alarm — note the channel and block number. 2. Review the commanded function against the SINUMERIK programming manual. 3. Check if the required machine option is enabled for this function. 4. Verify axis assignments and transformation settings are correct for the application. 5. Consult the Siemens SINUMERIK alarm manual for alarm 16746 specific remedy.

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Siemens SINUMERIK Controller

Spindle · Intermediate · 30-120 minutes

Alarm 16746

Siemens 840D 16746 - Channel block spindle selected gear stage not installed

Alarm 16746 fires when the NC program commands a spindle gear stage that exceeds the number of physically installed gear stages configured in MD 35090 ($MA_NUM_GEAR_STEPS). The 1st gear stage data block (GST1) does not contain definition data for the requested gear stage, causing a mismatch between programmed spindle selection and machine hardware configuration.

Siemens SINUMERIKSpindleIntermediate30-120 minutes

16746

Siemens 840D 16746 - Channel block spindle selected gear stage not installed

Channel block spindle selected gear stage not installed

Root Cause Summary

Alarm 16746 fires when the NC program commands a spindle gear stage that exceeds the number of physically installed gear stages configured in MD 35090 ($MA_NUM_GEAR_STEPS). The 1st gear stage data block (GST1) does not contain definition data for the requested gear stage, causing a mismatch between programmed spindle selection and machine hardware configuration.

Safety

Refer to Siemens documentation
Ensure qualified technician performs repairs

Causes and Fixes

1
Access SINUMERIK Control Panel > Maintenance > Machine Data > search MD 35090 ($MA_NUM_GEAR_STEPS). Note the currently configured value.
Do not modify this value without physical verification of installed gearbox stages.
2
Count the actual number of spindle gear stages installed on the machine hardware (inspect gearbox nameplate or mechanical documentation).
3
If the physical count exceeds MD 35090 value, increase MD 35090 to match installed gear stages. Verify the corresponding GST1 data block contains definitions for all stages via Siemens NC Data Manager or HMI > Spindle Data > Gear Stages.
Changes to MD 35090 require system restart (warm restart) and may require NCK reload.
4
Clear alarm (RESET), then test with a simple G97 command selecting each gear stage sequentially (e.g., M3 S1000 followed by spindle gear commands) to validate all stages are now accessible.

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