User manual

Section 6: Relative, Math, and dB Series 3700 System Switch/Multimeter Reference Manual
6-2 3700S-901-01 Rev. C / July 2008
Basic front panel REL procedure
1. Select the desired measurement function and an appropriate range setting.
2. Apply the signal you want to REL to a switching channel input or to the
Series 3700 inputs.
3. If you are using a switching module, close the input channel. (see Operation
keys (on page 4-17) for basic information about the front panel graphical
user interface).
4. Press the REL key to acquire the REL value. The REL annunciator will turn
on, but the displayed value will not become zero until a new reading is
triggered.
5. Apply the signal to be measured. The relative value will be subtracted from
the next reading that is triggered.
Pressing REL a second time disables the REL function. You also have the
option to manually enter a REL value rather than acquiring a value from an input
signal. To do this, select REL > LEVEL from the front panel and enter the value.
You will still need to enable REL by selecting the ENABLE menu item. You can
also perform a REL acquire from this menu. Note that pressing the REL key is
equivalent to doing an acquire followed by enabling REL.
NOTE You can perform the equivalent of REL manually by using the mX+b
(on page 6-4) math function. Set M for 1and B for any value you want.
REL remote operation
The dmm.rel.level() command specifies the REL value (for the active
function only), while the dmm.rel.acquire() command uses the input signal
as the REL value (again, for the active function only). The
dmm.rel.acquire() command is typically used to zero the display. For
example, if the instrument is displaying a 1µV offset, sending
dmm.rel.acquire() and enabling REL (dmm.rel.enable = dmm.ON)
zeros the display.
The following command sequence is equivalent to pressing the front panel REL
key:
dmm.rel.acquire()
dmm.rel.enable=dmm.ON
To manually set a REL value of 1.5 V, use this command sequence:
dmm.rel.level=1.5e-6
dmm.rel.enable=dmm.ON
For example, if the instrument is on the DCV function, the
dmm.rel.acquire() command is applicable to DCV measurements.