AMETEK BPS Series - Manual (Page 97)

User Manual AMETEK Programmable Power
BPS Series 97
load currents. When powering low power loads, measurement inaccuracies on rms and peak current
measurements will greatly affect derived measurements such as power, power factor and crest factor.
The measurement system on the BPS Series uses a data acquisition system with a 16 kHz bandwidth. This
means that high frequency components of the measured signal are filtered out. Any contribution to the rms
value of voltage and current above this cutoff frequency will not be reflected in the BPS Series
measurements. When using an external measurement reference, this may account for discrepancies in
readings.
5.4.4 Triggering Measurements
Both FFT results and waveform acquisitions may have to be positioned at a specific moment in time. To
allow the data acquisition to coincide with user specified events, the measurement system can be triggered
in different ways. Trigger modes are available from both the bus and the front panel. If one of the remote
control interfaces is used, acquisitions may also be triggered from the transient list system. Refer to the
programming manual for details on this mode of operation.
5.4.4.1 Trigger mode
The following trigger modes are supported by the BPS Series controller:
Single (SINGLE) This mode causes the acquisition system to be armed only once. The
BPS source waits for the user to press the ENTER key while on the
START field. As soon as the trigger event specified occurs, data is
acquired and the acquisition system is put in an idle state. A new user
initiated START event must be given to trigger a new acquisition.
This mode is appropriate for capturing events that occur only once
such as the inrush current when turning on a load.
Continuous (CONT) This mode causes the trigger system to re-arm itself after each trigger
event. Every time a new trigger event occurs, new data is acquired and
the LCD display is updated. No user intervention is required after the
initial START event.
This mode is appropriate for capturing repetitive events or to monitor
the source output continuously. Display updates will occur about once
per second.
5.4.4.2 Trigger source
The BPS Series controller offers a choice of trigger sources in front panel operation mode. The following
trigger sources are available from the TRIG SOURCE field:
Immediate (IMM) This mode causes a trigger to occur as soon as the ENTER key is
pressed with the cursor on the START field. No trigger source needs
to be specified for this trigger mode. This mode is equivalent to the
INIT:IMM:ACQ bus command.
This trigger source is appropriate if no trigger condition is known or
desired. When using this trigger source, the acquisition is always
triggered.
Phase (PHASE A) This mode causes the BPS acquisition system to wait for a specified
phase angle on the phase A voltage output. This allows the acquisition
to be positioned in time with respect to any phase angle on phase A, B
or C. Note that phase A, B and C are typically at 0°, 240° and 120°
with respect to the specified trigger phase in this field. An example of
this trigger source mode is shown in Figure 5-26.