ML2439A USB Power Meter User Guide : SCPI Commands : TRACe Data Array Commands
 
TRACe Data Array Commands
The TRACe group of commands is used to control the output of an acquired measurement array, which appears as a display trace when the power meter is in Graph mode. The TRACe commands provide outputting a channel’s entire internal display trace (501 measurement points) as one large array, or selecting and returning the array in smaller portions. These commands are useful for capturing the displayed waveform and importing it into a database on the host.
TRACe [:AVERage]]:DATA[:NEXT]?
Description:
Return a delimited array of power or voltage pixel average values corresponding to all or a portion of the graph mode display trace for the selected channel. The Average trace is the data shown when envelope display mode is inactive. Note that the pixel values are returned without regard to display vertical scale and center settings. The array will consist of COUNT trace pixel values, beginning at pixel number INDEX, up to the last pixel of the trace (index = 500), and will be returned in channel units. The selected channel must be “ON” to return measurement data.
Syntax:
TRACe[1|2|3|4][:AVERage]]:DATA[:NEXT]?
Returns:
P(index), P(index+1), P(index+2),…P(index+count) or V(index), V(index+1), V(index+2),…V(index+count)
Valid Modes:
All
 
TRACe:COUNt
Description:
Set or return the number of trace points, which will be returned each time the TRACe:DATA? query is issued. At the completion of each read, INDEX is automatically incremented by COUNT. If COUNT is set to a number greater than the number of points remaining in the trace, the array will be truncated. Setting COUNT to 501 (and INDEX to zero each time) will return the entire trace array.
Syntax:
TRACe[1|2|3|4]:COUNt <numeric_value>
Argument:
<numeric_value> = 1 to 501
Valid Modes:
All
 
TRACe:INDEX
Description:
Set or return the array index for the first trace point to be returned next time the TRACe:DATA? query is issued. Index 0 is the start of the trace buffer, and corresponds to the leftmost pixel on the graph display. Index 500 is the last point, and is the rightmost pixel. Each time a block of data is read, INDEX is automatically incremented by the COUNT value, so the full array can be split up into blocks of manageable size and read with successive TRACe:DATA? queries. INDEX must be reset to zero for each new trace that is to be dumped, whether or not all the points have been read.
Syntax:
TRACe[1|2|3|4]:INDEX <numeric_value>
Argument:
<numeric_value> = 0 to 500
Valid Modes:
All