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Siemens SINUMERIK Controller
Program/G-code · Intermediate · 30-120 minutes
Siemens 22320 - Block motion synchronous action: PUTFTOCF command could
ALARM 22320 occurs when the PUTFTOCF (fine tool compensation data block) cannot be cyclically transferred to the Channel Communication Frame because the designated transfer buffer is still occupied by a previous transfer operation. This indicates a synchronization failure between the NCK task scheduler and the PLC real-time communication interface managing tool offset updates.
22320
Siemens 22320 - Block motion synchronous action: PUTFTOCF command could
Block motion synchronous action: PUTFTOCF command could
The cyclic transfer of the PUTFTOCF data block (fine tool compensation) could not be performed because the transfer area is already occupied Control reaction: NC Start disable in this channel. Interface signals are set. Alarm display. NC Stop on alarm.
Root Cause Summary
ALARM 22320 occurs when the PUTFTOCF (fine tool compensation data block) cannot be cyclically transferred to the Channel Communication Frame because the designated transfer buffer is still occupied by a previous transfer operation. This indicates a synchronization failure between the NCK task scheduler and the PLC real-time communication interface managing tool offset updates.
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
Access Siemens HMI > Diagnostics > Alarms to capture the exact channel and block number from the alarm message. Cross-reference the block number in the NC program to identify which M-code or tool compensation function triggered the alarm.
- 2
In the NCK/PLC menu, navigate to Machine Data > Spindle > MD 32110 (CYC_TIME_CYCLE) and verify the cycle time interval. Compare against MD 32100 (TOOL_COMP_TIME) to ensure sufficient dwell time. If CYC_TIME_CYCLE is too short (< 50ms typical), increase the interval by 10-20ms increments.
Increasing cycle time may affect real-time responsiveness; validate against application requirements.
- 3
Examine the NC program for rapid successive PUTFTOCF calls or M-codes that invoke tool compensation without adequate inter-block delay. Add G04 (dwell) statements between compensation commands (minimum 100-200ms typical) to allow buffer clearance.
- 4
Monitor the 840D system diagnostics via HMI > System > Performance > PLC/NCK Load to confirm CPU utilization during tool offset operations. If NCK load exceeds 85%, reduce the frequency of PUTFTOCF calls or optimize PLC cycle time (MD 100).
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