The Function Generator; Introduction; General - Elektro-Automatik EL 9080-170 B Betriebsanleitung

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 or IU, are based 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
segments, 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 stick
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 EL 9080-170 B 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 12 mA/s. The maximum time which can be achieved with the minimum slope then calculates
as approximately 1379 seconds according to formula t
EA Elektro-Automatik GmbH
Helmholtzstr. 31-37 • 41747 Viersen
Germany
= rated value / min. slope.
Max
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
EL 9000 B Series
www.elektroautomatik.de
ea1974@elektroautomatik.de
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