to program by font keys the HP 3458A for a rolling average (mean)

[pelule]

Hope, there are some users of the 3458A out there, more experienced than me.

I like to make rolling average (mean) measurements with my 3458A.
Preferred to have a running average out of the last 8 or last 16 measures.
The 3458A shall operate stand alone (no connection to a computer).

Searched in the manual and the WWW (also in this blog), but could not find a solution.

With my Datron 1281 this is a quite easy job:
just select "AvR" in the "Math" menue and use the "Config" to set the "N" value to define the number of measurements to average.

Any ideas?

[DimitriP]

The only place I found about enabling Math operations is on page 118, and very deceivingly it seems , Math operations are enabled by sending a command via GPIB.

Hopefully someone else will chime in to confirm or deny ....

Anyone...  Bueler....



from the manual ( http://literature.cdn.keysight.com/litweb/pdf/03458-90014.pdf )
page 118

Enabling Math
Operations
To enable a math operation, send the MATH command (for real-time) or the
MMATH command (for post-process) followed by the operation parameter
(DB, DBM, FILTER, NULL, PERC, PFAIL, RMS, SCALE, STAT, or one
of the temperature-related parameters; refer to "Measuring Temperature,
later in this section for a listing of the temperature-related parameters). After
enabling a math operation, it remains enabled until you disable it, cycle
power, execute RESET, or execute one of the PRESET commands. For
example, to enable the NULL operation, send:
OUTPUT 722; "MATH NULL" !ENABLES REAL-TIME NULL OPERATION
or
OUTPUT 722; "MMATH NULL" !ENABLES POST-PROCESS NULL OPERATION

[pelule]

This fits to my findings so far.
A tip from a friend:
Use the user programming feature and define it to one of the user definable keys (as I did for the TEMP? command).
But we did not find the solutiion for the rolling average, just the one time average (STATS, MEAN).
My solution so far:
set the NPLC to 10*N, according to the manual, in case NPLC is > 10, the tools does N x (NPLC=10 measures) and builds the average.
-quote-
if you specify 60=PLCs (1 second of integration time at a 60 Hz = line frequency) using the NPLC command, the mulitmeter averages six 10 PLC readings.
-unquote-
But this is still no rolling average unfortunately.

[dacman]

The closest thing on the 3458A to a rolling average would be MATH FILTER.  It is definitely not a rolling average.  With NDIG 8 set, and others at default (NPLC 10 and DEGREES 20), I think it takes about 100 seconds to settle (with 60 Hz line power).  If DEGREES were set to 10, it would take about 50 seconds.  It's stated to act like a 1-pole RC low-pass filter.