[volt-nuts] HP 3456A Setup

[Charles P. Steinmetz]

>>1) Select "DC volts"
>>2) "Guard button" IN
>>3) "Auto Zero" ON
>>4) "Filter" OFF
>>5) "Auto Range" Selected
>>6) "INT" selected
>>7) enter-keys "6", "Store", "N DIG DISP" (#9 key)
>>8) enter-keys "100", "Store", N Cycles Int" (CHS key)
>>9) with Inputs shorted push "Math" "Off" (#0 key)
>>9a) then push "Math" "Null" (#3 key)

Note that step 9a turns on what other manufacturers call a "relative" 
or "tare" function -- it subtracts a reading taken immediately after 
the function is activated from all subsequent readings (untill Math 
Null is deactivated).  This is handy for cancelling the lead 
resistance for resistance measurements, for example.  But it is 
probably not what you want for normal DC measurements.  Instead, 
leave Null off and just let Autozero zero out the residual for each 
measurement.  If the meter has a zero error, you need to correct it 
-- not just subtract the zero error you got a while ago from the 
current reading.

Regarding the correct connection of the guard terminal, HP 
Application Note AN-123 provides a thorough discussion of what to do 
and why.  Connecting it to the Low input (as by pushing the Guard 
button in) is often suitable, but not always.

Best regards,

Charles