What causes Siemens SINUMERIK alarm 4270?

The specified machine data assigns a digital input/output byte or an analog input/output signal the processing of which has not been activated to an NC function.

How do I fix Siemens SINUMERIK alarm 4270?

1. Please inform the authorized personnel/service department. 2. Correct machine data. 3. Activate required inputs/outputs via MDs: MD10350 $MN_FASTIO_DIG_NUM_INPUTS MD10360 $MN_FASTIO_DIG_NUM_OUTPUTS MD10300 $MN_FASTIO_ANA_NUM_INPUTS MD10310 $MN_FASTIO_ANA_NUM_OUTPUTS Activation of fast inputs/outputs does not require the corresponding hardware configuration to be available at the control. 4. All functions using fast inputs/outputs can also be made use of by the PLC specification/modification defined in the VDI interface, if the response time requirements are reduced accordingly. 5. Activated inputs/outputs increase the computation time requirement of the interpolation cycle because the PLC manipulation signals are handled cyclically. 6. Note: Deactivate any inputs/outputs not in use. 7. Switch control OFF - ON

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Siemens SINUMERIK Controller

Parameter · Intermediate · 30-120 minutes

Alarm 4270

Siemens 4270 - Machine data assigns not activated NCK input/output byte

Alarm 4270 fires when machine data (MD) assigns a digital or analog I/O signal to an NC function, but the corresponding NCK input/output processing has not been activated via the enable parameter. This typically occurs when MD parameters reference I/O bytes without setting the associated activation flags in the NCK configuration.

Siemens SINUMERIKParameterIntermediate30-120 minutes

4270

Siemens 4270 - Machine data assigns not activated NCK input/output byte

Machine data assigns not activated NCK input/output byte

Root Cause Summary

Alarm 4270 fires when machine data (MD) assigns a digital or analog I/O signal to an NC function, but the corresponding NCK input/output processing has not been activated via the enable parameter. This typically occurs when MD parameters reference I/O bytes without setting the associated activation flags in the NCK configuration.

Safety

Only qualified personnel should diagnose and clear control alarms; follow the machine builder's safety procedures and lockout/tagout where hardware work is required.

Causes and Fixes

1
Navigate to Diagnostics > Machine Data (MD) menu and identify the problematic MD parameter number from alarm text %1. Cross-reference the I/O byte number %2 in the alarm message.
2
Locate the corresponding NCK activation/enable machine data parameter. For example, if MD10060 assigns spindle enable to byte 4, verify MD10010 (NCK spindle enable flag) is set to 1 or the appropriate activation value per SINUMERIK documentation.
Check MD parameter family: MD10xxx (spindle), MD11xxx (axis), MD14xxx (digital I/O), MD15xxx (analog I/O) for activation flags.
3
Set the NCK activation flag to the correct value (typically 1 or non-zero). Save machine data and perform a warm restart (NC Start button or Ctrl+Shift+R in MDI mode) to reload NCK configuration.
4
Verify the I/O byte assignment is valid (0-127 for digital, 0-255 for analog) and does not conflict with other MD assignments in the same range.

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