User manual

Series 3700 System Switch/Multimeter Reference Manual Section 13: Instrument Control Library (ICL)
3700S-901-01 Rev. C / July 2008 13-161
dmm.rel.level
Remarks
This is the relative offset level setting for the DMM. It applies to the selected function
as indicated by dmm.func (on page 13-137). Querying the setting when the selected
function does not support it will cause nil to be returned.
When relative measurements are enabled (see dmm.rel.enable (on page 13-159)), all
subsequent measured readings will be offset by the specified relative offset value.
Specifically, each returned measured relative reading will be the result of the following
calculation:
Relative reading = Actual measured reading – Relative offset value
The command will generate an error when dmm.func (on page 13-137) = "continuity"
or "nofunction". Also, an error will be generated if the value is out of range for the
selected function.
Changing functions with dmm.func (on page 13-137) will reflect the relative level offset
setting for that function.
The factory default and dmm.reset() (on page 13-161) function value is 0.
NOTE Using dmm.rel.level = dmm.measure() to set the REL level will
include math, limits, and filter operations, if enabled. However, using the
dmm.rel.acquire() (on page 13-158) function to set the REL level will not
use these operations, even if enabled.
Also see
dmm.rel.enable (on page 13-159)
Example
To perform an AC current measurement and use it as the relative offset value:
dmm.func = "accurrent"
dmm.rel.level = dmm.measure() -- see NOTE in Remarks
To acquire a relative offset value:
rel_value = dmm.measure() -- see NOTE in Remarks
dmm.rel.level = rel_value
To acquire a fresh REL level after using dmm.measure() (on page 13-150) to set one:
dmm.rel.enable = dmm.OFF
dmm.rel.level = dmm.measure() -- see NOTE in Remarks
dmm.rel.enable = dmm.ON
To acquire a REL level value for temperature (using dmm.rel.acquire() (on page 13-
158)):
dmm.func = "temperature"
rel_value = dmm.rel.acquire()
dmm.reset()
Function
Resets DMM aspects of the system, as indicated by the parameter.
Usage
dmm.reset(scope)
scope: A string equaling "active" for active function only to factory default settings or
"all" for all functions back to factory default settings.