Page 67
EPS Stromversorgung GmbH
Alter Postweg 101 • 86159 Augsburg
Germany
Fon: +49 821 / 570451-0
Fax: +49 821 / 570451-25
PSI 9000 3U Series
► How to save a sequence table (100 sequences) to a USB flash drive:
1.
Do not plug the USB flash drive yet or remove it.
2.
Access the function selection menu of the function generator via MENU -> Function Generator -> Arbitrary
3.
Tap on
, then
. The device will request you to plug the USB flash drive now.
4.
After plugging it, the device will try to access the flash drive and find the folder HMI_FILES and read the
content. If there are already WAVE_U or WAVE_I files present, they will be listed and you can either select
one for overwriting with
, otherwise select
for a new file.
5.
Finally save the sequence table with
.
3.9.11 Ramp function
The following parameters can be configured for a ramp function.
Value
Range
Description
Ustart / Istart
0...Nominal value of U, I
Start value (U,I)
Uend / Iend
0...Nominal value of U, I
End value (U, I)
t1
0,1 ms...36000 s
Time before ramp-up or ramp-down of the signal.
t2
0.1 ms...36000 s
Ramp-up or ramp-down time
Schematic diagram:
Application and result:
A
.st
ar
t
t
A
t1
t2
A
.E
nd
This function generates a rising or falling ramp between start
and end values over the time t2. Time t1 creates a delay before
the ramp starts.
The function runs once and stops at the end value. To have a
repeating ramp, function Trapezoid would have to be used instead
(see
Important to consider are the static values of U and I which define
the start levels at the beginning of the ramp. It is recommended
that these values are set equal to those in A.start, unless the load
at the DC output should not be provided with voltage before the
start of the ramp. In that case the static values should be set to
zero.
10h after reaching the ramp end, the function
will stop automatically (i.e. I = 0 A, in case the
ramp was assigned to the current), unless it
has been stopped manually before.
3.9.12 UI and IU table functions (XY table)
The UI and IU functions offer the user the possibility to set a DC output current dependant on the DC output volt
-
age, or a DC output voltage dependant on the DC output current. The function is table driven with exactly 4096
values, which are distributed over the whole measured range of actual output voltage or output current in the range
of 0...125% Unom or Inom. The table can either be uploaded from a USB flash drive through the front side USB
port of the device or via remote control (ModBus protocol or SCPI). The functions are:
UI function:
U = f(I)
IU function:
I = f(U)
In the
UI function
, the equipment measuring circuit determines the level from 0 to maximum of the output current.
For each of the 4096 possible values for output current a voltage value is maintained by the user in the UI table
which can be any value between 0 and nominal value. The values uploaded from a USB flash drive will always
be interpreted as voltage values even if the user calculated them as current values and incorrectly loaded them
as a UI table. The UI function suits very good for the simulation of fuel cell characteristics.
