Elenos ETG2500, User Manual

Page: 27 / 78

27 Product description
Current management on the power supply (Lifextender) ®
This is activated when the maximum current for continuous operation of the power sup-
ply is exceeded. This value is set below the deliverable current limit and constitutes the
threshold which can be exceeded only for short periods (maximum 1 minute at a time).
Should this situation arise, the “PSU current derating” function is activated (alarm “013”
and if necessary alarm “014”) and the ALC management algorithm, envisaged for nor-
mal operating conditions, is replaced by another one wherein the VDS control and Bias
is determined by the power set and, with even higher priority, by the current delivered
by the power supply.
The current derating condition is deactivated when the power delivered returns to the
value set by the user and if the maximum current delivered by the power supply is less
than or equal to the maximum value allowed for continuous operation.
Thermal management on the power supply (Lifextender) ®
The power supply management algorithm according to the temperature, is the same as
that on the RF unit and is logically connected in “OR” to the latter.
The first Derating level (acting directly on the output power) is activated when the
power supply temperature exceeds 75°C, while the second level is activated - if the first
is ineffective - if the temperature does not stabilize below this value. In the latter case,
the output power is brought below – 3 dB with the same procedure as that described
for the RF section.
The activation of this feature is shown on the display as alarm “015” and possibly
“016”.
Fault Management on the RF modules (Lifextender) ®
This manages the maximum deliverable power according to the number of RF amplifier
modules considered to be operating correctly.
If one or more MOSFETs are considered faulty (this happens when the absorbed cur-
rent is 10% below the average value), the RF output power is reduced to the expected
value when a fault occurs and the fans rotation speed is activated at the maximum
value. The fault case study and corresponding maximum power is described through a
complex table obtained through tests. It is designed to stop the fault spreading and to
prevent
the MOSFETs that are still working from being put under excessive strain by the ALC
mechanism (which would require them to provide all the missing output power).
In order to avoid a ridiculously high number of alarm SMSs, no messages are sent du-
ring this phase: the alarm SMS, if validated, is only sent after the adaptation procedure
of the output power according to the table parameters and only if the -3dB condition
occurs on the output power.
The activation of this feature is shown on the display as alarm “008” and “009”.
Cooling Management on the fan unit (Lifextender) ®
According to the actual cooling requirements, the rotation speed of the fans is adju-
sted from a minimum of 60% to a maximum of 120% approx. (these values may vary
according to the models of fan used). The cooling requirement is evaluated based on
accurate measurements of the temperature in the vicinity of the RF MOSFETs and the
power supply unit. The Cooling Management aims to extend the useful life of the fans,
minimize the quantity of dust which can be transported by the air flow and allow the
safe operation of the equipment also under extreme temperature conditions.
Without Lifextender, the fans always operate at 100%.