Measurement Configuration

AC Signal Filter

DC Input

Resistance

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.

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.

Table 2-4. AC Signal Filters

 

 

 

 

 

 

AC Voltage or Current

AC Filter

Max Reading Rate for

 

 

Input Frequency

Selected

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

 

 

 

 

 

 

 

 

 

 

 

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.

The HP E1412 Multimeter’s input resistance is normally fixed at 10MΩ for all dc voltage ranges to minimize noise pickup. You can set the input resistance to greater than 10GΩ 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.

Table 2-5. DC Voltage Input Resistance

 

 

 

 

 

 

 

DC Input Resistance

DC Input Resistance

 

 

 

100mV, 1V, 10V Ranges

100V and 300V Ranges

 

 

 

 

 

 

 

INP:IMP:AUTO OFF

10MΩ

10MΩ

 

 

(DEFAULT)

 

 

 

 

 

 

 

 

 

INP:IMP:AUTO ON

>10GΩ

10MW

 

 

 

 

 

 

 

 

 

 

 

•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.

Chapter 2

HP E1312A/E1412A Multimeter Application Information 37