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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
PSI 9000 15U/24U Series
3.10.2.3
Resolution
Amplitudes generated by the arbitrary generator have an effective resolution of approx. 52428 steps. If the am
-
plitude is very low and the time long, the device would generate less steps and set multiple identical values after
another, generating a staircase effect. It is furthermore not possible to generate every possible combination of
time and a varying amplitude (slope).
3.10.2.4
Possible technical complications
Operation of switching mode power supplies as a voltage source can, when applying a function to the output volt
-
age, lead to damage of the output capacitors due to continuous charging/discharging which causes overheating.
Furthermore the actual voltage progression may differ from what’s expected.
3.10.2.5
Minimum slope / maximum ramp time
When using a rising or falling offset (i.e. DC part) at functions like ramp, trapezoid, triangle and even sine wave,
a minimum slope, calculated from the rated values of voltage or current, is required or else the adjusted settings
would be neglected by the device. Calculating the minimum slope can help to determine if a certain ramp over
time can be achieved by the device or not. Example: model PSI 9080-1020 is going to be used, with 80 V and
1020 A rating.
Formula: minimum slope = 0.000725 * rated value / s
. For the example model it results in ΔU/
Δt of 58 mV/s and ΔI/Δt of 740 mA/s. The maximum time which can be achieved with the minimum slope then
calculates as approximately 1379 seconds according to formula
t
Max
= rated value / min. slope.
3.10.3
Method of operation
In order to understand how the function generator works and how the value settings interact, the following should
be noted:
The device operates, including in function generator mode,always with the three set values U,I and P.
The selected function can be used on
one
of both the values U or I, the other two are then constants and have a
limiting effect. That means if, for example, a voltage of 30 V is set for the DC output, a load is connected and a
sine wave function should operate on the current with an amplitude of 800 A and offset 1000 A, then the function
generator will create a sine wave progression of current between 200 A (min) and 1800 A (max), which will result
in an output power between 6 kW (min) and 54 kW (max). The output power, however, is limited to its set value.
If this were 45 kW then, in this case, the current would be limited to 1500 A and, if clamped to an oscilloscope, it
would be seen to be capped at 1500 A and never achieve the target of 1800 A.
3.10.4
Manual operation
3.10.4.1
Function selection and control
Via the touchscreen one of the functions described above can be called up,
configured and controlled. Selection and configuration are only possible when
the output is switched off.
►
How to select a function and adjust parameters
1.
While the DC output is switched off tap the touch area
on the main screen.
2.
In the menu overview tap on the touch area
and then on the desired function.
Note: This touch area is locked as long as R mode (adjustable resistance) is activated.
3.
Depending on the choice of function there follows a request to which value the function generator is going
to be applied:
or
.
4.
Adjust the parameters as you desire, like offset, amplitude and frequency for a sine wave, for example.
5.
Adjust the overall limits of voltage, current and power, which you can access with touch area
.
Setting the various functions is described below.
