Siemens LME7 Series Basic Documentation

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Building Technologies Division Basic Documentation LME7... CC1P7105en
Infrastructure & Cities Sector 27 PWM settings 29.11.2011
27.4.3 Final settings of PWM safety parameters

Note:
PWM control by the LME7... makes use of the Hall signal for feedback. This Hall
signal is used to calculate the manipulated variable of the PWM control process. To
prevent the calculation of wrong manipulated variables in the event of incorrect Hall
signals, the working range of PWM control must be restricted via parameter
675.00/675.01. For that purpose, the burner is operated in special test mode
(parameter 559).
Warning!
In the case of burner components (PWM fan) with voltage-related behavior, it is
recommended to read out the value (current PWM signal, parameter 920) for the
prepurge phase (P30) with the minimum permissible prepurge speed close to the
undervoltage limit, and for the ignition phases (P38, 40 and 44) with the maximum
permissible ignition speed close to the overvoltage limit. If this is not observed, there
is a risk of loss of safety functions.
Procedure
Select test mode (parameter 559) and check the prepurge speed under worst-case
conditions close to the undervoltage limit, or check the ignition load speeds under
worst-case conditions close to the overvoltage limit:

Reference:
In test mode (parameter 559, setting value = 2), the normalized PWM signal
(parameter 675.00) for the prepurge phase or the PWM signal (parameter 675.01) for
the ignition phase is output as a fixed value. Start the burner and check the speed, the
volumetric air flow or air pressures under these worst-case conditions by taking
appropriate measures while ensuring compliance with the relevant standards (e.g. EN
676).
 Set safety parameter 675.00 to the value previously determined by parameter 920
in the prepurge phase (P30) -1% and safety parameter 675.01 to the value of
parameter 920 in the ignition phase (P38, 40 and 48) +1%
Follow these steps
 Select programming mode for the OEM
 Press
A
and
F
simultaneously for <5 seconds. Display shows CodE
 Enter the OEM’s password via
, and
/
reset
. Also see chapter Entering the
password
 Display changes from PArA to 400: SEt
 Press
to select the next parameter group (P500...P600). Display shows
500: PArA
 Press
/
reset
to go to the respective group
 Press
or to select parameter 559
 Press
/
reset
 Press
or to set the value (2 test modes)
 Press
/
reset
to transfer the setting value to the onboard memory
 By pressing
ESC
twice (press and simultaneously) you leave the
parameter setting level and return to the parameter group
 Press
to select the parameter group (P600...P700). Display shows 600: PArA

Siemens LME7 Series Specifications

General

Brand	Siemens
Model	LME7 Series
Category	Controller
Language	English