Siemens SIMATIC S5 Manual page 342

Troubleshooting
Error Code
Recovery Procedures
FB6 Error in position control loop
There is no change in the actual position even though the analog voltage
(setpoint speed) exceeds 5 V. The current operation is aborted and mode 4
(follow-up mode) automatically started. In follow-up mode, the position
controller is off. Follow-up mode can be terminated at any time. The
position controller is then reenabled.
Possible causes:
- Encoder not connected, incorrectly connected or defective
- The module's analog output is not wired
- The power section is not switched on or not enabled
- The axis is blocked by an obstacle of some kind or is jammed.
FB7 PLC failure
FB8 Invalid path specification
FB9 Invalid tool offset
FBA Invalid G function for dimensional unit "degrees"
FBB Path specification not in BCD code
FBC EEPROM not programmable!
FBD EEPROM failure!
FBE No data in EEPROM/RAM !
FD0 Only one continuous loop permitted
FD1 No end of loop
FEC Printing
FED Printer not ready!
10-16
IP 266
Cross-
Reference
Section 5.1.7
Kap. 5.3.15
Section 5.4.2
Section 5.4.2
EWA 4NEB 812 6057-02