Pilz PSS SB FT, Basic license - Manual (Page 151)

Modular Block System: Burner Management 6-107
Spurious signals at NEXT input
Only when Bit 0 to Bit 5 from NEXT is carried out in ascending order is the
RDY-bit sample changed step-by-step.
Individual steps, i.e.
NEXT bits on the input cannot be missed out. Returns
(loop backs) are not possible. If this is not maintained the enable is
cancelled in all cases. The enable is triggered again when all
NEXT bits
are reset. A new cycle is started exclusively when Bit 0 from NEXT is set.