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HP E1312A/E1412A Multimeter Application Information 37Chapter 2
Measurement Configuration
This section contains information to help you configure the multimeter for
making measurements. The parameters discussed in this section give you
measurement flexibility when using the
CONFigure command.
AC Signal Filter The HP E1412A Multimeter has three different ac filters which enable you to
either optimize low frequency accuracy or achieve faster ac settling times for
ac voltage or ac current measurements. Only these functions use the ac filter.
NOTE: These reading rates account for only the AC filters behavior.
See Page 36 for the effect of DC blocking circuitry.
• The ac filter selection is stored in volatile memory. Default is the
medium filter (20Hz - 300kHz) at power-on or after a module reset.
• The CONFigure and MEASure:<function>? commands automatically
select the medium (20Hz) filter.
• Use the [SENSe:]DETector:BANDwidth 3 | 20 | 200 | MIN | MAX
command to change the ac filter selection following a
CONFigure
command. The
MIN parameter will select the 3Hz filter and the MAX
parameter will select the 200Hz filter.
DC Input
Resistance
The HP E1412 Multimeter’s input resistance is normally fixed at 10M
Ω
for
all dc voltage ranges to minimize noise pickup. You can set the input
resistance to greater than 10G
Ω
for the 100mVdc, 1Vdc and 10Vdc ranges
to reduce the effects of measurement loading errors. You select increased
input resistance using the
INPut:IMPedance:AUTO ON command and this
applies to the dc voltage function only.
• The input resistance setting is stored in volatile memory.
INPut:IMPedance:AUTO OFF is set at power-on and after a module
reset.
• The CONFigure command and the MEASure:<function>? command
automatically turn
AUTO OFF. Use INPut:IMPedance:AUTO ON
after a
CONFigure command to set it ON.
Table 2-4. AC Signal Filters
AC Voltage or Current
Input Frequency
AC Filter
Selected
Max Reading Rate for
Adequate Settling
3 Hz to 300 kHz Slow filter 1 reading/7 seconds
20 Hz to 300 kHz Medium filter 1 reading/second
200 Hz to 300 kHz Fast filter 10 readings/second
Table 2-5. DC Voltage Input Resistance
DC Input Resistance
100mV, 1V, 10V Ranges
DC Input Resistance
100V and 300V Ranges
INP:IMP:AUTO OFF
(DEFAULT)
10MΩ 10MΩ
INP:IMP:AUTO ON >10GΩ 10MW