F01001 — FloatingPoint exception

The Control Unit has raised a FloatingPoint exception: an operation with the FloatingPoint data type produced an invalid condition — for example a division by zero, an overflow or an underflow, as the cause bits below encode. The drive trips with OFF2. The manuals attribute the exception to the basic system or to an OA application: the technology functions FBLOCKS and DCC, with TEC named additionally on G130, G150, S120 and S150. The fault value itself is marked as relevant only for internal Siemens troubleshooting; the diagnosable detail sits in r9999.

• An exception occurred during an operation with the FloatingPoint data type in the Control Unit.
• The error can come from the basic system or from an OA application — the manuals name the technology functions FBLOCKS and DCC, and additionally TEC on G130, G150, S120 and S150.

1. Carry out a POWER ON — switch-off/switch-on — for all components.
2. Check the configuration and signals of the blocks in FBLOCKS.
3. Check the configuration and signals of the DCC charts.
4. Check the configuration and signals of the TEC charts (this step is given on G130, G150, S120 and S150).
5. Upgrade the firmware to a later version.
6. Contact Technical Support.

• %1 in the message text is the fault value, which the drive stores in r0949. The manual states: Fault value (r0949, interpret hexadecimal): Only for internal Siemens troubleshooting.
• r9999 holds the further information the fault refers to: r9999[0] fault number, r9999[1] program counter at the time when the exception occurred, r9999[2] cause of the FloatingPoint exception.
• The drive encodes the cause in r9999[2] bit by bit:
  • Bit 0 = 1: Operation invalid
  • Bit 1 = 1: Division by zero
  • Bit 2 = 1: Overflow
  • Bit 3 = 1: Underflow
  • Bit 4 = 1: Inaccurate result

• r0949 — fault value: read it in hexadecimal after the trip; for this code the manual marks it as serving only for internal Siemens troubleshooting.
• r9999 — internal supplementary software-error diagnostics: read index [0] for the fault number, [1] for the program counter at the time of the exception and [2] for the coded cause (see the bit list above).

This fault is acknowledged only by a POWER ON: switch the power supply off and on again for all components before the drive is restarted. That switch-off/switch-on is also the first step of the remedy; if the fault comes back, continue with the configuration checks of the FBLOCKS, DCC and TEC charts, a firmware upgrade and, as a last step, Technical Support.