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Siemens SINUMERIK Controller
Program/G-code · Intermediate · 10-30 minutes
Siemens 14020 - Block wrong value or wrong number of parameters on function or
SIEMENS alarm 14020 occurs when the NC program calls an M-code that has no corresponding function defined in the PLC program or machine data. This typically happens when M-codes are programmed without proper PLC interface configuration or when using incorrect M-codes for the specific machine configuration.
14020
Siemens 14020 - Block wrong value or wrong number of parameters on function or
Block wrong value or wrong number of parameters on function or
- An illegal parameter value was specified in a function or procedure call. - An illegal number of actual parameters was programmed in a function or procedure call Control reaction: Correction block is reorganized. Interface signals are set. Alarm display.
Root Cause Summary
SIEMENS alarm 14020 occurs when the NC program calls an M-code that has no corresponding function defined in the PLC program or machine data. This typically happens when M-codes are programmed without proper PLC interface configuration or when using incorrect M-codes for the specific machine 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
Check M-code in part program
Identify the specific M-code causing the alarm from the NC program line displayed in the alarm message.
- 2
Verify PLC program M-code table
Access PLC program and check if the M-code is defined in the M-code interface table (typically in OB1 or dedicated M-code function blocks).
- 3
Add M-code definition to PLC
If missing, add the M-code definition in the PLC program with appropriate function block and compile/download the PLC program.
Ensure machine is in safe state before downloading PLC program changes.
Call a technician if:
- ·PLC program modifications required
- ·Machine data changes needed beyond operator level
- ·Interface hardware issues suspected
Prevention
- Maintain updated M-code reference list for your specific machine
- Validate part programs against machine capabilities before production
- Regular backup of working PLC programs
Common Mistakes
- Using M-codes from different machine manuals
- Forgetting to download PLC program after modifications
- Not checking M-code range in machine data
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Always verify with your machine manual or a certified technician before performing service procedures.