axismd.ai
Siemens SINUMERIK Controller
System · Intermediate · 30-120 minutes
Siemens 840D 4077 - New value of MD not set. Requested bytes too much
Alarm 4077 occurs when attempting to write a new Machine Data (MD) value that would exceed available NCK user memory capacity, preventing the write operation to protect existing user memory contents. This is a memory allocation conflict where the requested MD parameter size plus existing data exceeds the configured memory pool.
4077
Siemens 840D 4077 - New value of MD not set. Requested bytes too much
New value of MD not set. Requested bytes too much
Siemens SINUMERIK 840D system notice 4077: New value of MD not set. Requested bytes too much. This is a system-level notification regarding machine data or configuration. Note the message details and take the indicated action.
Root Cause Summary
Alarm 4077 occurs when attempting to write a new Machine Data (MD) value that would exceed available NCK user memory capacity, preventing the write operation to protect existing user memory contents. This is a memory allocation conflict where the requested MD parameter size plus existing data exceeds the configured memory pool.
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Navigate to Diagnostics > Machine Data > Memory Configuration and note the current NCK user memory utilization percentage and available free space.
- 2
Identify the specific MD parameter (%2 in alarm message) and cross-reference its data type and array size in the SINUMERIK documentation. Verify the requested allocation size (%3 bytes) against available pool.
- 3
Clear unused tool offsets, geometry data, or custom macro variables via NCK > User Memory > Delete User Data, or reduce the array dimension of the target MD parameter.
Backup all active offsets and configuration data before deletion.
- 4
Retry the MD write operation. If persistent, verify MD memory pool size settings (typically MD10200-MD10299 range) are correctly configured for your machine's application needs.
Seeing Multiple Alarms?
Seeing another alarm with this one? Enter the code.
Get machine-aware diagnosis
AxisMD logs alarms against your actual machines, tracks patterns, and gives AI context your manual doesn't have.
Start freeWas this guide helpful?
Always verify with your machine manual or a certified technician before performing service procedures.