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Series 3700 System Switch/Multimeter User's Manual
Section 5: Basic Digital Multimeter (DMM) Operation
3700S-900-01 Rev. C / July 2008
5-27
When measuring resistance >10K-ohms, cable and 3700 card capacitance,
along with dielectric absorption, can cause additional uncertainties, such as low
readings. The low readings are caused by insufficient settling time after the
closure of a Model 3700 switch card channel. Auto delays have been optimized
to allow proper settling after the close of a channel. Refer to the Auto Delay
table for additional details. If the application requires an additional settling delay,
use the following ICL commands to the channel or slot of interest:
channel.setdelay("4004", 0.050)
adds 50msec of delay after
closing channel 4 in slot 4.
dmm.setdelay("slot4", 0.050)
adds 50msec of delay to all
channel in slot 4.
Offset compensated ohms (OC+)
The presence of thermal EMFs (voltages) can adversely affect low-resistance
measurement accuracy. To overcome these unwanted offset voltages, you can
use offset-compensated ohms on the 1 , 10 , 100 , 1k , and 10k ranges for
the 4 function.
Optimizing low ohm measurement and speed
When measuring resistance 100-ohms or less, cable, connectors, and Model
3700 switch cards can have thermal offsets, which can result in additional
reading uncertainties. Auto delays for <=100-ohms have been optimized for
throughput and settling, resulting in the best measurement. If the above
conditions cause additional uncertainty, adding a delay of 10msec can improve
accuracies. Refer to the Auto Delay table for additional details. If the application
requires additional settling delay, use the following ICL commands to the
channel or slot of interest:
channel.setdelay("4004", 0.010)
adds 10msec of delay after
closing channel 4 in slot 4.
dmm.setdelay("slot4", 0.010)
adds 10msec of delay to all
channels in slot 4.