Variable output impedance control on Battery Channel (#1) 29
Optimizing measurement speed
Auto Zero State
In general, to optimize speed of any application code, you should turn auto zero
off. To turn auto zero off, use the AUTO ZERO STATE option under the Main
Menu or send the following command over the bus: SYSTem :
AZERo:STATe 0
.
The system auto zero state setting indicates whether background readings are
taken. A background reading is an internal calibration measurement taken by the
power supply between user triggered readings. The selected function dictates
how many background readings are taken between user triggered readings.
Certain settings, such as changes to integration time, force backgrounds to
update regardless of this state. Other changes, such as changing voltage level
settings, don't force backgrounds to update if already updated. When
backgrounds are forced to update, all must be refreshed before a user triggered
reading can be measured.
When auto zero state is set to ON, background readings continuously refresh by
cycling when the instrument is idle. When auto zero state is set to OFF,
background readings do not occur after being updated unless a change forces
them to update. When a change forces an update, the background readings get
updated once and stop until the next change forces an update.
To refresh the backgrounds when the state is OFF, set the state to ON then back
to OFF. This will refresh the backgrounds only once and stop after that.
Programming examples
Programming examples for methods of combining commands to speed up
measurements:
*rst
' restore factory default settings
syst:azer:stat 0
' turn auto zero state off
disp:chan 1
' sets active channel to battery
sens:func 'curr'
' select the current measurement function
volt 3
' set output voltage to 3
curr 1
' set current limit to 1
sens:nplc 0.5
' set nplc to 0.5
outp on
' turn the output on
NOTE
For faster measurements, the NPLC can be as short as 0.002