Siemens LMU54 Series - Sequence Times; Standby; Startup

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Siemens Building Technologies Basic Documentation LMU54... / LMU64... CC1P7494en
HVAC Products 3 Functions 07.11.2002
According to the sequence diagram, there is a permitted tolerance band with an upper
and a lower limit for each level (e.g. «N_ZL»), which is defined via parameter
«N_XX_Delta».
The relevant sequence phases (refer to the sequence diagrams) are queried for these
limits.
Example: Ignition load upper limit = «N_ZL» + «N_ZL_Delta»
lower limit = «N_ZL» - «N_ZL_Delta»
These limit values are complemented by «NoG_Null» and «NoG_Max» (refer to the
sequence diagrams).
«NoG_Max» is the maximum speed that must never be reached. «NoG_Null» is the low
speed that must be crossed when changing to standby.
Time
Min.
(s)
Max.
(s)
Response
at end of
Description
TNB 0.2 21.0 Lockout position Afterburn time
TLO 0.2 51.0 Lockout position Open LP
TNN 0.2 51.0 Lockout position Down to speed = 0
THL1 0.2 51.0 Lockout position First fan runup time
THL2 0.2 51.0 Lockout position Second fan runup time
tv 0 51.0 Switching Prepurging
TBRE 0.2 51.0 Lockout position Brake time until ignition load is reached
TW1 0.2 51.0 Lockout position
Waiting for internal sequence, speed
readjustment and optimization of
combustion
tvz 0.2 5.0 Switching Preignition time
TSA 1.8 9.8
1)
Ignition safety time
tsa1 0.2 9.6
2)
1)
Ignition safety time with ignition
tsa2 0.2 TSA-tsa1
2)
1)
Ignition safety time without ignition
ti 0.2 10 Switching Interval operation
tn 0 51.0 Switching Postpurging
1)
Lockout position or start repetition, depending on the flame signal and the parameter;
various parameterization choices (refer to relevant description)
2)
With parameterization with abortion of safety time in the case of flame detection, the times
of «tsa1» and «tsa2» are derived from the time of establishment of flame. It should be
noted, however, that «TSA» can never be exceeded
The following phases (with associated times in parentheses) are relevant with one
startup / shutdown cycle:
• PH_STANDBY (unlimited): Burner control waits for a heat demand signal from the
controller
• PH_STARTVER: No external or internal release, relevant diagnostic code is delivered
The change from «Standby» to «Operation» is the startup triggered by a heat demand
signal from the controller.
If startup takes place with prepurging, startup will commence with the «PH_THL1_1»
phase; if no prepurging is used, with the «PH_THL1_2» phase.
Sequence times
Standby
Startup