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EA Elektro-Automatik GmbH
Helmholtzstr. 31-37 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
www.elektroautomatik.de
ELR 9000 HP Series
3.10.13.6 Possible reasons for battery test stop
The battery test function run can be stopped by different reasons:
•
Manual stop on the HMI with button STOP
•
After the max. test time has been reached and action “End of test” was set for it
•
After the max. battery capacity to consume has been reached and action “End of test” was set for it
•
Any device alarm which would also switch off the DC input, like OT
•
Passing the threshold U
DV
(discharge voltage), caused by whatever reason
After an automatic stop, caused by any of the listed reasons, the test cannot be continued or
run again immediately. The full battery configuration has to be run through, accessible via touch
area BACK.
3.10.14 MPP tracking function
MPP stands for the maximum power point (see principle view
to the right) on the power curve of solar panels. Solar inverters,
when connected to such panels, constantly track this MPP once
it has been found.
The electronic load simulates this behaviour by a function. It can
be used to test even huge solar panels without having to connect
a usually big solar inverter device which also requires to have a
load connected to its AC output. Furthermore, all MPP tracking
related parameters of the load can be adjusted and it so is much
more flexible than an inverter with its limited DC input range.
For evaluation and analysis purposes, the load can also record
measured data, i. e. DC input values such as actual voltage, cur-
rent or power, to USB stick or provide them for reading via digital
interface.
The MPP tracking function offers four modes. Unlike with other
functions or general use of the device, values for the MPP tracking
are only entered by direct input via the touch screen.
3.10.14.1 Mode MPP1
MPP
Po
w
er
Voltage
This mode is also called “find MPP”. It is the simplest option to have the electronic load find the MPP of a connected
solar panel. It requires to set only three parameters. Value U
OC
is necessary, because it helps to find the MPP quicker
as if the load would start at 0 V or maximum voltage. Actually, it would start at a voltage level slightly above U
OC
.
I
SC
is used as an upper limit for the current, so the load would not try to draw more current than the panel is speci-
fied for.
Following parameters can be configured for tracking mode
MPP1
:
Value Range
Description
U
OC
0...Nominal value of U Voltage of the solar panel when unloaded, taken from the panel specs
I
SC
0...Nominal value of I
Short-circuit current, max. specified current of the solar panel
Δt
5 ms...65535 ms
Interval for measuring U and I during the process of finding the MPP
Application and result:
After the three parameters have been set, the function can be
started. As soon as the MPP has been found, the function will
stop and switch off the DC input. The acquired MPP values of
voltage (U
MPP
), current (I
MPP
) and power (P
MPP
) are then shown in
the display.
The time of a function run depends on the parameter Δt. Even with
the minimum setting of 5 ms one run take already a few seconds.
