Section 5: Basic Digital Multimeter (DMM) Operation
Series 3700 System Switch/Multimeter User's Manual
5-8
3700S-900-01 Rev. C / July 2008
DCV input divider
Normally, the input resistance for the 100mVDC, 1VDC, and 10VDC ranges is
>10GΩ, while the input resistance of the 100VDC and 300VDC ranges is 10MΩ.
However, the input resistance for the three lower DCV ranges can also be set to
10MΩ by enabling the input divider.
With the input divider enabled, the measurement INPUT HI is connected to
INPUT LO. Also, some external devices (such as a high voltage probe) must be
terminated
to a 10MΩ load. The input divider maintains the measurement of
open leads near 0V. Also, internal I
BIAS
through the 10M causes an open input to
read <-0.4mV. With a short circuit (and the input divider on or off), the short
circuit to read <
V.
The input divider can be enabled from the front panel when function is "dcvolts"
by pressing the
CONFIG
key, then the
DMM
key. To control the divider over the
bus, use the
dmm.inputdivider
remote programming command.
Connections
WARNING
Even though the Series 3700 can measure up to 300V, the
maximum input to a switching module may be less.
Exceeding the voltage rating of a switching module may
cause damage and create a safety hazard.
Make sure the insulation and wire sizes used are
appropriate for the voltages and current being applied to
the Series 3700 analog backplane connector. Use
supplementary insulation as needed. Exceeding the voltage
rating of a wiring may cause damage and create a safety
hazard.