Pilz PNOZ m1p base unit - Manual (Page 49)

4.4 Burner cycle
4 Burners
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4.4.2 Errors during the burner cycle
Errors during the burner cycle 4- Funktionsbeschreibung_Schritte_Verhalten_im_Fehlerfall
An error is detected if the input signals within a step fail to match the val-
ues set for the monitoring operation. This will lead either to a fault lock-
out or a safety shutdown, depending on the input signal and
configuration. Some of the monitoring functions during a burner cycle
depend on the step, while others are continuous. In other words, some
monitoring processes occur in a specific step, while others may be ac-
tive across the whole cycle.
 Step-dependent errors
With step-dependent errors, the set value of the input signals in the
various steps may vary.
E.g.: With combustion air monitoring, the input must have a "0" signal
during the "Check start conditions" step and a "1" signal during the
"Burner in operation" step.
The following monitoring functions have errors that depend on the
specific step:
– Combustion air monitoring
– Flame monitoring of ignition flame
– Flame monitoring of main flame
– Tightness control
– Compound controller not in pre-purge position
– Compound controller not in ignition position
– Ignition and operation safety chain
 Step-independent errors
Where errors are independent of the specific step, the same set value
applies for each step: The input must have a "1" signal.
The following monitoring functions have errors that are independent
of the specific step:
– Safety chain 1
– Safety chain 2