EVAL-ADE7756EB Datasheet, PDF (6/15 Pages) Analog Devices – Evaluation Board Documentation AD7756 Energy metering IC

PRELIMINARY TECHNICAL DATA
EVAL-ADE7756EB
ADE7756 EVALUATION SOFTWARE
The AD7756 evaluation board is supported by Windows
based software which will allow the user to access all the
functionality of the ADE7756. The software is designed to
communicate with the ADE7756 evaluation board via the
parallel port of the PC.
Installing the AD7756 Software
The ADE7756 Software is supplied on three 3.5'' 1.44MB
floppy disks. The minimum requirements for the PC are
Pentium II 233MHz, 32 MB RAM, 10MB free HD space
and at least one PS/2 or ECP parallel port . To install the
software place disk #1 in the floppy drive and double click
"setup.exe". This will launch the set up program which
will automatically install all the software components
including the uninstall program and create the required
directories. When the set up program has finished install-
ing the "ADE7756Eval" program the user will be
prompted to install the National Instruments run-time
engine. This software was developed using National
Instruments LabView software and the run-time engine is
required in order to run the "ADE7756Eval" program.
When prompted simply place disk #2 in the floppy drive
and hit return. Follow the on-screen instructions to
complete the installation. You will need to reboot your
computer to complete the installation.
To launch the software simply go to the
Start—>Programs—>ADE7756 menu and click on
"ADE7756Eval".
Metering Mode
When the software is launched, the program automatically
starts in Meter Mode. In this mode the evaluation board
can be used as a fully functional energy meter. When the
appropriate line voltage, test current, frequency, and meter
constant have been set up, the user can use the calibration
routine to remove any error associated with the transduc-
ers. The CF output can be used with a standard frequency
counter to check the accuracy. The measured CF output
frequency should be adjusted to match the theoretical CF
freq. of the Eval software.
Note that the calibration routine does not automatically
remove phase errors associated with a CT or other
transducer. These must be removed first by using the
ADE7756 PHCAL Register. This is explained later.
Instantaneous Power, Voltage, and Current RMS calcula-
tions are also available in this window. They are processed
using the Waveform Sampling routine with the number of
samples defined in this mode.
Uninstalling the ADE7756 Evaluation Software
Both the "ADE7756Eval" program and the NI run-time
engine are easily uninstalled by using the Add/Remove
Programs facility in the control panel. Simply select the
program to uninstall and click the Add/Remove button.
Figure 8 - Meter Mode
Note also that the input signal range and gain must be set
for the PGAs on the Channel 1 and Channel 2. This will
ensure that the output signal range from the transducers is
matched to the analog inputs. For example, in the meter
example shown in Figure 6 the line voltage is attenuated
to approximately 215mV rms or 300mV peak. By select-
ing a gain of 2 for the PGA in Channel 2, the peak
differential input signal is set to 500mV. Similarly for
Channel 1, assuming a maximum current of 120A the
maximum differential output signal from the CT is
300mV. Therefore the full-scale differential input signal
level is set to 500mV by setting the gain to 2—see Table I
in the ADE7756 data sheet. The PGA settings are made
through the main selection menu. To get to the main
selection menu click the "Quit to Menu" button at any
time.
Figure 7 — Uninstalling the ADE7756 Eval Software
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REV. PrB 01/01