Siemens SIMATIC S5 Manual page 205

The Standard Function Block FB164
The parameter BFEH (module error) has signal state"1" when the IP247 positioning module sig-
nals an error. The type of error can be identified from
:
Active bit:
The module is executing the transferred job (BA 1...BA 17).
The "active bit" is set by function block FBI 64 when a job (BA 1,..BA 17) is transferred to the posi-
tioning module. After executing or abandoning the job, the active bit is reset by the IP247 (=>
Section 6.2.6 "Relationship between the Parameter TBIT and the current Checkback Signals").
BTR :
Output of the mode currently set on the IP247 module.
MFKT :
During automatic operation (BA 8 and 9) the M functions programmed in the automatic program
are output by the IP247 (=> Section 2.6.9 "The M Function"). In all other modes M02 is output.
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flag byte FY254