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positive or negative power, energy, and cost results may be displayed. When negative power
measurements are allowed, it is necessary to have all current probes connected properly. Use the
Checkout Connections feature or view all the waveforms before taking measurements. Failure to do so
will typically result in power readings 1/3 of the correct value.
The 2 Current Probe mode (also known as 2 wattmeter mode) is a method of calculating total power
using only 2 current probes and 2 phase-to-phase voltages. This power measurement mode is
discussed in the
Voltage Measurement Mode
section since it has direct effects on the measurement
and display of voltages.
Changing the Power Measurement Mode in ATPOL II
To determine which power measurement mode ATPOL II is in, simply press the [Measure Mode] key
three times and read the display. If ATPOL II is in Always Positive Power measurement mode, the
display will read "Power Readings Always Positive". If ATPOL II is in Negative Power Allowed
measurement mode, the display will read "Negative Power Readings Allowed". To change the power
measurement mode from what is displayed, press the [No/Reject] key and then press [Yes/Accept]
when the desired measurement mode is displayed.
The power measurement mode that you choose will stay in effect until you change it. It will not be
changed by turning ATPOL II off.
Changing the Power Measurement Mode in PSM
To determine the power measurement mode using PSM, connect ATPOL II to PSM and then either go
to the Setup Data menu and read what appears in the Power Mode box or operate in Remote Control
mode and press the key combinations described above.
To change the power measurement mode using in PSM, either
go to the Data Setup menu, click on the Power Mode drop-down
box, select the mode that you wish to operate in, and then send
the new setup to the connected ATPOL II meter or operate in
Remote Control mode and press the key combinations described above.
Defining Inputs
All current probes used by ATPOL II are self-identifying so they are automatically calibrated to the unit
when they are plugged in. This is a convenience, a time saver, and a protection against making errors
in measurements. There are occasions where the input does not represent what it actually is. In these
cases, the user needs to define the inputs for ATPOL II or for PSM.
The chief need for defining inputs is to enter in input ratios for voltage or current. There are several
occasions when this is necessary. The most common occurs when monitoring a large main circuit to a
facility. The current may be too large to measure with the current probes you own, or you may not be
able to physically clamp around the cables or bus bar, or the voltage of the bar may exceed the
insulation rating of the current probe. In these instances a permanently installed CT and/or PT may be
wired-in for a metering system. By clamping onto the secondary of such a CT (typically with an AT6003
probe) or attaching directly to the PT with voltage probes, you obtain readings proportional to the
primary side of the CT or PT. Entering the ratios of the CT and/or the PT into ATPOL II allows all
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