Automatic Load Recognition - Caen ELS LiAM 6005 User Manual

LiAM User's Manual

3.5 Automatic Load Recognition

An automatic procedure to estimate load resistive value was implemented in
order to guarantee more efficient and safe operation on the LiAM power supply units.
By running the "MTUNE\r" command the power supply automatically start a
procedure that recognizes the connected load resistive value by setting the output
current to pre-defined levels (±1A value), then measuring the output voltage and
storing the content in the internal non-volatile memory.
Once launched, the entire procedure last 13 seconds so that the module
communication is not accessible by the user during this time interval.
The procedure result is R
where V and I
OUT OUT
values respectively. Maximum value for R
This resistance value is then stored (only if the process is successful) in the
module internal memory and it is used into normal operation to perform diagnostics
(e.g. regulation fault routine) and to operate the Adaptive Rail Switching.
In order to check if the estimated resistive value of the load has been correctly
estimated, the user needs to send to the power supply an 'MRR\r' command that
returns the value of the last stored resistance.
Please note that in order to make the computed R
module operation, a 'MUP\r' command needs to be sent to the power supply unit.
Example 1.
Consider now running the automatic load procedure by sending an
'MTUNE\r' command to the power supply connected to a magnet load. The R
value computed from this procedure is found to be 4.35Ω. In normal operation, the
LiAM power supply automatically recognizes that the maximum required output
voltage for this load is equal to:
where "5A" is the maximum output current rating of the power supply.
The load connected to the LiAM unit would then never need the voltage rails
to be at HIGH level and into normal operation then only the MID voltage
configuration will be used, thus drastically reducing the internal power dissipation of
the module.
43
[Ω], computed as follows:
EST
are the output voltage [V] and output current [A] readback
EST
|
is 25Ω.
value take effect in the
EST
LiAM Description
EST