Pilz PSS SB FT, Basic license - Manual (Page 120)

6-76 Modular Block System: Burner Management
Standard Function Blocks
Blocks required
• DB002: Will be made available when the configurator is called up
• DB015: Administration data block
DB015 must consist of its total length of 1024 data words and
have READ/WRITE access (see also the section “Administrati-
on data blocks DB015, DB016 and DB017” in chapter 5).
• OB101: To call up SB157.
• SB152: The output parameter ENBL from SB152 (BR_START) must
be supplied to the input parameter SyOK of SB157.
In addition SB152 is responsible for the error reaction. The
output parameter
STEP from SB152 must be supplied to the
input parameter of the same name from SB157.
• SB157: IGNI_TRY
• SB255: Operating system call up
Programming guidelines
• Operand of input parameter BIT0
The step flag bit 0 of the byte-parameter NEXT from SB158 must be
assigned to this parameter, so that the step “Switch-on ignition
transformer” can be recognised.
• Operand of input parameter BIT3
The step flag bit 3 of the byte-parameter NEXT from SB158 “Ignition”
must be assigned to this parameter, so that the step “Pilot flame
established” can be recognised.
• Operand of input parameter FLAs
The operand must be assigned to this parameter, which also must
appear on the same named input parameter from SB152 “Burner: start
and operator elements”, in order to recognise a faulty flame signal.
• Operand of output parameter RDY
If this output is set for one pulse length, then the step flag NEXT from the
previous step must be set from the step “Switch-on ignition transformer”.
This will ensure that the sequence will start with the initial ignition attempt
after a failed attempt has occurred and so will not be pre-purged.
SB157