Pilz PSS SB FT, Basic license - Manual (Page 100)

6-56 Modular Block System: Burner Management
Standard Function Blocks
SB155: Pre-purge
Block header
Input parameters
• SSNR: Safety subroutine number
Permitted value range: 1 ... 200
Format: Byte-constants KB 001 ... KB 200
(further information about the
SSNR can be found in the
sections “Administration data blocks DB015, DB016 and
DB017” and the “Input Parameter
SSNR” in chapter 5).
Value of DW0000/DB015 = 0: no error present
• NEXT: NEXT = 1: activate “pre-purge” step
• COND: Limit switch for maximum position of the air damper or monitor
maximum air flow
COND = 1: Limit switch is operated
Output parameters
• ENBL: Enable flag bit
ENBL = 1: this function is fault-free
(refer also to Programming guidelines)
• RDY: Ready signal
RDY = 1: “Pre-purge” is active
Function
Monitoring the limit switches for the maximum position of the air damper or
the maximum air flow during the pre-purge time.
SB155
PREPURGE
B - SSNR
X - NEXT
X - COND ENBL - X
RDY - X