Pilz PSS SB FT, Basic license - Manual (Page 81)

Modular Block System: Burner Management 6-37
Restart after flame failure or flame monitoring fault
When AuSt = 1 and FTRY = 1 SB152 can begin an automatic restart once
only after flame failure or flame monitor interference. Burner start-up will
only be initiated if the safety sequence and the monitor sequence have not
responded, no interference is present and the flame and the flame
monitoring block does not signal a fault.
After air pressure has been built-up,
monitoring is activated by a pulse at the
NEXT input. The RDY output signals this
activation.
The
RDY output is used as the step
enabling condition for the sequence.
The ENBL output is set by
a start pulse, provided all
criteria are met (
ERR,
GUAR, CHAI, FLAs)
When RUN = 1,
“Burner in operation” is
signalled.
Flame failure of flame
monitor interference.
The
ENBL is reset
After the interference is
removed (
FLAs = 1), the
ENBL output is set again.
By a new, second
flame failure or flame
monitor fault, the
ENBL output is not set
again. Only after a
reset and a start pulse
is the
ENBL set again.