Page 71
EA Elektro-Automatik GmbH
Helmholtzstr. 31-37 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
www.elektroautomatik.de
PSB 9000 3U Series
3.11
The function generator
3.11.1 Introduction
The built-in
function generator
(short:
FG
) is able to create various signal forms and apply these to the set value
of either voltage or current.
The standard functions are based on an
arbitrary generator
and directly accessible and configurable using manual
control. In remote control, the fully customisable arbitrary generator replicates these functions with sequence points
containing 8 parameters each.
The following functions are retrievable, configurable and controllable:
Function
Short description
Sine wave
Sine wave generation with adjustable amplitude, offset and frequency
Triangle
Triangular wave signal generation with adjustable amplitude, offset, rise and fall times
Rectangular
Rectangular wave signal generation with adjustable amplitude, offset and duty cycle
Trapezoid
Trapezoidal wave signal generation with adjustable amplitude, offset, rise time, pulse time, fall
time, idle time
DIN 40839
Simulated automobile engine start curve according to DIN 40839 / EN ISO 7637, split into 5 curve
sequences, each with a start voltage, final voltage and time
Arbitrary
Generation of a process with up to 99 freely configurable curve points, each with a start and end
value (AC/DC), start and end frequency, phase angle and total duration
Ramp
Generation of a linear rise or fall ramp with start and end values and time before and after the ramp
Battery test Battery discharge test with constant or pulsed current, along with Ah, Wh and time counters
MPP Track-
ing
Simulation of the characteristic tracking behaviour of solar inverters when seeking to find the maxi
-
mum power point (MPP) when being connected to typical sources such as solar panels
3.11.2 General
3.11.2.1 Limitations
The function generator is not accessible, neither for manual access, nor for remote control, if resistance mode
(U/R adjustment, also called UIR) is active.
3.11.2.2 Principle
The device features a built-in function generator (short: FG), but the entire unit cannot be considered as high power
function generator, because its power stages are only post-connected to the FG. Primarily in source mode, the
typical characteristics of a voltage and current source remain. Rise and fall times, caused by capacitor charge/
discharge, affect the resulting signal on the DC terminal. While the FG is able to generate a sine wave with 1000
Hz or higher, the device will never be able to follow the generated signal 1:1. Source and sink mode will slightly
differ from each other regarding the results, while the sink mode will be generally better, because primarily focused
on current.
Depiction of principle:
Effect of the DC power stages on functions:
FG
PSB
DC
+
‐‐
C
The resulting wave on the DC terminal heavily depends on the frequency resp. period of the selected wave, its
amplitude and also the voltage rating of the device. The effect of the capacities on the wave can be partially com
-
pensated. In source mode and when running voltage dynamics to which the capacities have the biggest impact
on it can help to put an additional load to the DC terminal in order to decrease rise and fall times. This extra load
has a positive impact on periodic functions like rectangle or sine wave.
