Pilz PSS SB FT, Basic license - Manual (Page 111)

Modular Block System: Burner Management 6-67
° Open safety valve
→
VAV1 = 1
° Main valve closed
→
VAV3 = 0
° Exhaust valve closed
→
VAV4 = 0
° Test output
→
GP- = 0
° Test output
→
GP+ = 0
- NEXT, Bit 03 = 1: Testing for gas pressure
° Enable
→
ENBL = 1
° Seal check step 4 is active
→
RDY, Bit 03 = 1
° Safety valve closed
→
VAV1 = 0
° Main valve closed
→
VAV3 = 0
° Exhaust valve closed
→
VAV4 = 0
° Test output
→
GP- = 0
° Test output
→
GP+ = 1
- NEXT, Bit 04 = 1: Seal check ended
° Enable
→
ENBL = 1
° Seal check step 5 is active
→
RDY, Bit 04 = 1
° Safety valve closed
→
VAV1 = 0
° Main valve closed
→
VAV3 = 0
° Exhaust valve closed
→
VAV4 = 0
° Test output
→
GP- = 0
° Test output
→
GP+ = 0
Timing diagrams
Signal cycle of uninterrupted tightness control on a plant with an exhaust valve
The NEXT input in the byte-format controls the SB cycle similar to that of a
step sequence.
The cycle is started with a single, continuous “1” from bit 0 to bit 4.