Pilz PSS SB FT, Basic license - Manual (Page 146)

6-102 Modular Block System: Burner Management
Standard Function Blocks
L M90.00 . main valve SB156
O M90.01 . main valve SB159
= A01.00 . main valve
• Resetting the sequence
To ensure the main valve seal when a shutdown occurs, the operand
used for the
ENBL from SB152 must be assigned to the input parameter
SyOK of SB159.
If the
ENBL of SB152 changes from “0” to “1” then SyOK of SB159 is
also set. The sequence block SB149 detects a positive edge and resets
the whole sequence as well as
NEXT from SB159.
• Shutdown
If SyOK = 0 or if an error is present (see error messages), a shutdown
occurs:
° No enable
→
ENBL = 0
° Set-up step not active
→
RDY = 0
° Close main valve
→
VAV3 = 0
° Reset control enable
→
REGL = 0
° Main flame not established
→
RUN = 0
° Monitor main flame
→
FLAM = 1
SB159
SB159
RUN
B - SSNR
B - NEXT
X - SyOK ENBL - X
RDY - B
VAV3 - X - M 90.01 .main valve. SB159
REGL - X
RUN - X
FLAM - X