Pilz PSS SB FT, Basic license - Manual (Page 77)

Modular Block System: Burner Management 6-33
Programming guidelines
• Use the global inputs for the error sequence ERR, the monitor
sequence GUAR and the safety sequence CHAI
An automatic restart due to an interrupted error sequence or monitor
sequence is only possible, if the error sequence or monitor sequence is
reset and
AuSt = 1.
If the safety sequence is interrupted, the error must be removed and a
manual reset carried out via the reset (
RSET) and the start button
( STRT)! The block enable will only be issued if the safety sequence is
reset and no longer interrupted.
NOTICE
The error reaction is the sole responsibility of the user. When
selecting elements for error, monitor and safety sequences, all the
safety-related aspects must be taken into account!
A programming example can be found in Chapter 8 under “Managing
enables”.
• Linking the output parameter ENBL
To ensure the valve seal if a shutdown occurs, the operand assigned to
the
ENBL must be assigned to the input parameters SyOK of SB156
“Tightness Control” (if available), of SB158 “Ignition” and SB159 “Run”.
To control the ignition attempts, the operand assigned used for the
ENBL
must also be assigned to the input parameter SyOK of SB157 “Ignition
Attempts”
• Linking the output parameter STEP
The operand for the output parameter STEP from SB152 must also be
assigned to the input parameter STEP of SB149 and also to the input
parameter STEP of SB157, if SB157 is used. This will enable the
individual steps of the sequence to reset during burner start-up.
The operand for the parameter STEP has the value 1 for the duration of
a cycle when a positive edge of the ENBL of SB152 is detected.
If several burners are operated with one PSS, each burner must be
assigned its own STEP operand. This enables the burners to be
controlled and monitored separately (see example under the description
of SB149).