Pilz PSS SB FT, Basic license - Manual (Page 74)

6-30 Modular Block System: Burner Management
Standard Function Blocks
Output parameters
• ENBL: Enable flag bit
ENBL = 1: this function is fault-free
(see also Programming guidelines)
• RDY: Ready signal
RDY = 1: the step “Build up minimum air pressure” ended
correctly. The next step of the sequence is enabled.
• STEP: signals burner stat-up for the duration of a cycle.
STEP = 1: first cycle of burner start-up
STEP = 0: no burner start-up detected
This parameter must be assigned with the operand also
assigned to the input parameter
STEP of SB149 and SB157
“Ignition attempts” for the same burner.
Function
• Monitoring the flames (pilot and main flames) from burner start-up to
operating position until burner switch-off (controlled or safety shutdown
or fault lock-out)
• Restart after a controlled shutdown
• Allows a restart once only after a controlled shutdown, which has been
triggered because of a flame failure during operation.
• Monitoring the air pressure monitor, after the time has elapsed for
building-up minimum air pressure.
• Evaluating the reset, start and stop button
• Monitoring global signals from the error, monitor and safety sequences
• Carrying out a delayed start-up after the system has started so that the
safety, error, monitor and flame monitoring sequences can supply a
positive acknowledgement signal for the global signal inputs.
SB152