VTI Instruments EX1401, Руководство пользователя

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56 EX1401 Web Page Operation
under “Current Value” is not necessarily part of a record – it is simply the newest data in the
instrument’s circular buffer FIFO.
Any records in the instrument FIFO can be downloaded by clicking the “Download CSV” button in
the Measurement section. The “Download Records” field indicates how many records will be
removed from the FIFO and converted to CSV format for download. Checking the “All” box causes
the SFP to download all available records instead.
Measured data can also be plotted in the Data Plot section of the SFP. The following options are
available:
•
Plot Type controls the plot’s mode of operation and has two options:
o
Poll Current Value Table will plot each new data point that is polled from the
Current Value Table in real time, whenever a measurement is running. When
this mode is selected, the following parameters are available:
▪
CVT Polling Frequency (ms) controls the amount of time waited
between polling of the instrument’s measurement state and Current
Value Table. Valid values are from 100 to 10000 ms.
▪
Maximum CVT Points is the maximum number of Current Value
Table points to plot at one time. After this many points is reached, the
oldest will be removed from the plot whenever a new one is added.
Valid values are from 8 to 512.
o
Download Records From FIFO allows records to be downloaded from the
instrument’s FIFO and plotted directly in the SFP. When this mode is selected,
the following buttons are available:
▪
Plot Next FIFO Record pops a record from the FIFO, downloads it,
and adds it to the current plot.
▪
Clear Plotted Records removes all currently plotted records. Because
all data is plotted on a common time-axis, adding data that was
acquired far apart in time can create a large gap in the plot. It is
recommended to clear the plot before adding more data if the next
record is not close in time to the already plotted data.
▪
Save Plotted Records downloads all currently plotted data in CSV
format.
•
Draw Points controls whether a marker is drawn on each plotted data point, in addition
to the line. Turning this on is helpful with small data sets, but with large amounts of data,
it can slow down plotting significantly, as well making the plot itself less readable.
All channel data is plotted via a shared Y-axis, in the selected units for each channel, even if not all
channels are configured to use the same units. If
Report CJC is enabled for any channels, the CJC
data is plotted on a separate Y-axis, which is placed to the right of the plot area.
The plot’s X-axis is always the time axis, in units of seconds. The values on the axis will always be
offset by the seconds portion of the first plotted point’s time value after clearing the plot (FIFO
mode) or starting a new measurement (CVT mode). The offset value will be displayed next to the
X-axis label. For instance, if the timestamp of the first plotted value is 34.567, the X-axis label will
read “Seconds (+34)” and the first plotted value will appear at 0.567 seconds on the plot. This allows
large IEEE 1588 time values to be plotted without crowding the X-axis tick labels.
Hovering the mouse pointer over any plotted point will pop up a message identifying the channel
name, as well as both the X- and Y-axis values for the point. X-axis values in this message are the
full offset-corrected values.
DIO data cannot be plotted via the SFP. But, if the DIO Reporting Enabled property is True, any
DIO records associated with plotted channel data records will be included in CSV data that is
downloaded via the
Save Plotted Records button.