The THD of voltages and currents can
be easily included in (or removed from) your logs.
All versions of PS3000 are capable of measuring and
recording THD values in data logs. The requirements
and methods to do so vary, depending on the firmware
and options installed.
Determining if the unit has the
required options installed. To include THD
measurements in a log, the Harmonics Option [order
HAO], the Logging Option [ order LOG], and the PC
Control/Analysis Option [order PCCA] must be
installed in your PowerSight unit.
To check for these options, follow
this procedure:
1. Press the Admin key
of your PowerSight unit (it’s at the lower left).
2. If the display is “Identify
Unit?” press the Yes key. If not, press the
No key repeatedly until it “Identify Unit?” is
displayed and then press the Yes key.
3. Part of the display will be
“FW:” followed by a number (such as “FW:2.9a”).
That number is the firmware version
that is loaded in the unit. Write the firmware
version number down for use in the next sections.
4. Press the Yes key.
The display will be “Identify Options?” Press the
Yes key again.
5. The display will be
something like "Options: HLS4M67". The “H” indicates
that the Harmonics Analysis Option is installed. The
“L” indicates that the Data Logging Option is
installed. The “S” indicates that the PC
Control/Analysis option is installed. The first three
characters must be “HLS" for THD measurements to be
included in logs. If they aren’t, contact us to have
the options installed.
Procedure for units with firmware of
2.88 or higher The previous section explained how to
determine what the firmware version of the unit is.
If it is 2.90 or higher, follow the procedure of this
section. If it is lower than this, follow the
procedure of the next section.
Please Note: There are trade-offs in
recording THD into a log. PowerSight units with
firmware version 2.9 and higher take 4 seconds for
each thorough measurement of THD. During this time,
all other measurements are suspended. The
measurements are done once each logging period and
then are added to the log. If all seven THDs (3
voltages and 4 currents) are included in the log, it
could take 28 seconds to do all the calculations. For
this reason, care should be taken when deciding
whether to add THD measurements to the log. If a new
maximum or minimum voltage or current occurred during
the THD calculation time, it would be missed. Also,
if a short logging period is desired, such as 1
second, the effective time between records could be
7*4+1= 29 seconds, which might be unacceptable. For
these reasons, THD variables are not part of the
default log measurements. The remainder of this
section tells how to add them to the log.
The procedure to add THD measurements
to (or to remove THD measurements from) logs is as
follows:
1. Turn your PowerSight unit
on and connect it to your computer, using the serial
communications cable.
2. Run your PSM (PowerSight
Manager) software. The PSM software must be version
2.10 or higher.
3. The main menu of PSM must
indicate that PowerSight is successfully connected.
The Connection information box must have a green bar
at the top and display “Unit Connected”, “Serial
Comm: enabled”, “Data logging: enabled”, and
“Harmonics: enabled”.
4. Click on the word
“DataLogging” at the top of the main menu screen.
Then click on “Advanced Data Logging Setup”. The
Advanced Data Logging Setup screen will now appear.
(click on "data setup" button for 3.1 version
software)
5. If the PowerSight unit was
successfully connected, the existing log setup will
be shown. Click on the “Detail” button at the bottom.
6. The “Log Details” screen
will be displayed. Each measurement type that can be
included in the log has a box for it. If the box is
checked, then the measurement type is included in the
log (for instance, if the upper left box is checked,
then phase A average voltage will be included in each
record of the log).
7. There is a row for
selecting the three THD voltages and a row for
selecting the four THD currents. Click on the boxes
to select or de-select each of the THD measurements.
As you do so, notice that the log capacity
information at the upper left is affected since you
are affecting the log capacity by changing the
measurements. When you are done, click on “OK”.
8. Now click on “Save to
PowerSight” to load this new setup into PowerSight.
You may also want to click on “Save to File” in order
to save the setup for future use.
Once you have successfully loaded the
setup into PowerSight, it will remain there until you
change it in the future. Turning the unit off will
not affect it. Procedure for units with firmware of
2.87 or lower The first section explained how to
determine what the firmware version of the unit is.
If it is 2.87 or lower, follow the procedure of this
section. If it is higher than this, follow the
procedure of the previous section.
