SATEC EM720 Operation Manual - Manual (Page 106)

Chapter 5 Configuring the EM720
Configuring Recorders
106 EM720 Power Quality and Revenue Meter
Configuring the Waveform Recorder
The EM720 can store waveforms in three log files.
Configurable waveform log files #1 and #2 can record
waveforms at four programmable sampling rates: 32, 64,
128 or 256 samples per cycle. A log file can store up to 7
channels simultaneously (three voltage channels and four
current channels) with a programmable length and up to 20
pre-event cycles.
Waveform log #3 is pre-configured for fast transient
recording. It is only operational in the EM720T and stores 1-
cycle transient waveforms sampled at a rate of 1024 samples
per cycle. If you have a basic EM720 model, you can remove
this file to free more memory for other files.
The waveform record length depends on a recording option
you can select for each configurable waveform file:
• Fixed recording time: a triggered waveform is recorded
up to the maximum specified length. Other events that
may be triggered before the recording ends may not
be recorded completely if they extend beyond the
recording time.
•
Event-controlled recording time: a waveform will
extend for as long as trigger conditions exist plus a
user-defined post-event time of up to 2048 cycles
(possibly extended to complete a file record). The
maximum length for an active trigger is limited to
avoid continuous triggering. The minimum record
length can be extended by post-event time if needed.
NOTE
In event-controlled mode, waveform triggering on end of a
PQ or fault event, or by a pulsed event (like a voltage
transient or timer-triggered events), which have no
duration, can only record minimum-length waveforms that
may be extended by a user-defined pre-event and post-
event time.
The minimum waveform length that can be recorded is 512
samples of the input signal, or 0.5 to 16 cycles depending on
the selected sampling rate. It is the size of physical records
the waveform recorder uses to store waveforms to files.
Whenever a waveform ends before the last file record is
completed, it extends up to the file record size.
If a waveform file is configured to store more samples per
event than a single file record can hold, the recorder stores
as many records as required for recording the entire event.
The file records in a series are identified by the same series
number, so they may be easily linked and plotted together.
To configure a waveform log file:
1. Double click on a waveform log partition with the left
mouse button.