Load Monitoring (Lm) - d&b audiotechnik D40 Reference Manual

d&b D40 Reference manual 1.5 en
5. Run System check
↳ Executing a System check after the event will repeat the
measurement and display all values that are outside of the
tolerance band, indicating a possible damage to the system
components.
When a system is repeatedly used in the same
configuration for which a calibration file exists, the System
check procedure can also be used before the show to
verify the system's correct setup.
A System check will only provide valid impedance values, if
the amplifier has been calibrated before the check with the
load connected or if a valid calibration file has been
loaded using R1.

7.7.2 Load monitoring (LM)

Features
The d&b Load monitoring function is related to the System check
function and serves to identify a possible loudspeaker malfunction.
Function
The calibration process, performed from the System check menu
with the system fully set up, determines the impedance for each
channel and calculates the related upper and lower impedance
limits.
While the system is operating, d&b Load monitoring continuously
monitors the load impedance separately for both frequencies. It
detects any changes in loudspeaker impedance and reports an
error if the limits are exceeded. For this purpose, Load monitoring
uses inaudible pilot signals which are faded in for approximately 5
seconds in user defined intervals.
NOTICE!
The resolution of Load monitoring regarding failures of single
components depends on the type and the number of loudspeakers
connected to each channel.
The maximum number of cabinets which can be operated in
parallel by one amplifier channel in order to be able to detect a
failure of a loudspeaker component is given in the d&b R1
Software help (Þ within R1 press F1).
Load monitoring does not work if the amplifier is switched off or
switched to standby mode.
Load monitoring setup
On the «System check» screen, selecting «LM setup» opens the
corresponding subscreen.
The «Load monitoring setup» menu provides all relevant
parameters for adjustment to the on-site requirements.
Load Activates Load monitoring. The On/Off status
monitoring is also indicated on the System check and
On/Off Channel setup screens.
Once a fault has occurred, switching off Load
monitoring will also reset the error and error
message.
LM Period The maximum time it takes the system to detect
a loudspeaker malfunction. The intervals of the
pilot signal are derived from this parameter.
The time can be set in a range from 40 to
1000 sec. in 40 sec. detents.
Channel setup
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