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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
The function generator
3.10.1 Introduction
The built-in function generator is able to create various signal forms and apply these to the set value of voltage
or current.
The standard functions are based on an
arbitrary generator
and directly accessible and configurable using manual
control. For remote control, the fully customisable arbitrary generator replicates the functions with sequences
containing 8 parameters each. Further functions, such as UI-IU, are bases on a table with 4096 values, working
as
XY function
.
Battery test
and
MPP tracking
are software based functions only.
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
UI-IU
Table (.csv) with values for U or I, uploaded from an USB flash drive
Battery test
Battery discharge test with constant or pulsed current, along with Ah, Wh and time counters
MPP Tracking
Simulation of the characteristic tracking behaviour of solar inverters when seeking to find the
maximum power point (MPP) when being connected to typical sources such as solar panels
3.10.2 General
3.10.2.1 Limitations
The function generator is not accessible, neither for manual access, nor for remote control, if resistance mode (R/I
adjustment mode, also called UIR mode) is active.
3.10.2.2 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).
The XY generator, which works in table mode, has an effective resolution of 3276 steps for the set value range of
0-100% rated value.
3.10.2.3 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 ELR 9080-170 HP is going to be used, with 80 V and
170 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 13 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.
