Pilz PSS SB FT, Basic license - Manual (Page 139)

Modular Block System: Burner Management 6-95
Failure of SyOK in all NEXT steps
Spurious signals at MANU and S_IG inputs
The block function continues irrespective of signal changes at MANU and
S_IG.
The ENBL is always reset with the failure of SyOK.
ENBL is set together with SyOK . If at this time a NEXT
signal appears when setting the
SyOK signal, the
corresponding output bit sample is set.