Pilz PSS SB FT, Basic license - Manual (Page 145)

Modular Block System: Burner Management 6-101
Programming guidelines
• ENBL
The negative edge of the enable ENBL from SB159 must set a flag to “0”
for the duration of one PSS-cycle. This pulse flag must be supplied to the
AND-operation before the global input
ERR or to the AND-operation
before the global input CHAI from SB152 “Burner: Start and operator
elements”. The decision to use ERR or CHAI depends on the user and
the respective standards regarding error reaction.
ERR: If an error is present a controlled shutdown is carried out, when
AuSt = 1 with restart
CHAI: If an error occurs a safety shutdown is carried out.
A programming example can be found in Chapter 8 under “Managing
enables”.
• Driving the main valve VAV3
The situation could arise where the main valve VAV3 is driven
simultaneously by SB156 “Tightness control” and SB159 “Run”.
Aid: Assign different flags to the output parameter VAV3 from SB156 and
for VAV3 and the output parameter VAV3 from SB159 for VAV3. After
calling up the SB, perform an OR-operation on both flags and drive the
corresponding peripheral output with the result of this logic operation.
Example:
SB156
TIGHT_C
B - SSNR
B - NEXT
X - SyOK
X - V4?
X - P+
X - P-
W - T_V
Z - T
ENBL - X
RDY - B
VAV1 - X
VAV3 - X - M
90.00 .main valve SB156
VAV4 - X
GP+ - X
GP- - X