Load Of Ignition - Siemens LMV5 Series Technical Instructions

LMV Series
LEGEND - Password Access: (U)=User, (S)=Service, (O)=OEM, Shaded = Commonly Used, ** = Must Set, X = Has Function, / = Partial Function
Menu Path Parameter
Startmode (O)
Params & Display>
O2Contr/Alarm>
Load of Ignition (O)
Gas/Oil Settings >
Startmode
O2InitOffset (O)
NumberTauSuspend (S)
Adjust. Temp O2 (U)
SCC Inc.
Default Range
Sets how the LMV52.4 transitions from lightoff to operation. Four possibilities exist:
1) standard - after lightoff at set ignition positions, LMV5 is immediately released to
modulate on the position control (fuel air ratio) curves. O2 trim will engage after a period of
time defined by (Tau Low-Fire x NumberTauSuspend ) plus an additional 4x Tau Low-Fire .
This is how past LMV52s have functioned.
standard 2) Ign Load TC - does not use set ignition positions. Varies ignition positions based on
Ign Load TC ambient temperature and the setting of parameter Load of Ignition .
standard
IgnPtWithTC 3) IgnPtWithTC - uses set ignition positions, but will vary the positions of the air influenced
IgnPtWoutTC actuators when transitioning from lightoff to low fire based on ambient temperature.
4) IgnPtWoutTC - uses set ignition positions, and will vary the positions of the air influenced
actuators when transitioning to low fire based on learned characteristics of the burner.
NOTE: Start modes other than standard will all hold the LMV5 at StartPointOp (low fire)
until a time defined by (Tau Low-Fire x NumberTauSuspend ) has passed, or the measured
%O2 is within +/- 0.2% of setpoint. See Section 6 for more detail.
When Startmode is set to "IgnLoadTC", this defines the load at which the burner will be
0% 0-100%
ignited. If another start mode is selected, parameter has no effect.
For start modes other than standard, this will bias the manipulated variable so that the
transition from lightoff to lowfire can be more rich (negative values) or more lean (positive
0% -2-2% values). Offset is in %O2, even 1% gives a substantial offset. Can also be used to shorten the
release to modulation time (by bringing down the measured %O2 to +/- 0.2% faster) for start
modes other than standard.
After burner ignition, the air inside the boiler and stack is slowly replaced with the products
of combustion. Only after this replacement is complete can accurate, representative O2
readings be taken by the O2 sensor. This also determines the low fire waiting time if the
10 5-140
Startmode is not set to "standard". The value of NumberTauSuspend multiplied by Tau
Low-Fire determines the time at which representative O2 readings can be taken by the O2
sensor mounted in the stack.
Temperature as read by the ambient air temperature sensor when the last point of the O2
Read Only
control curve was commissioned. Used as the basis for the temperature for the compensated
(TC) start modes.
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