User`s guide

7-34 Agilent 4155C/4156C User’s Guide Vol.2, Edition 6

Measurement Units and Functions

Measurement Time

Measurement time depends on integration time, measurement range, and other

measurement conditions, and can be expressed by the following formula:

Measurement time = Integration time + Overhead time

Integration time is the time required for measurement, and does not include range

changing, data compensation, and so on which would be the overhead time.

Integration Time

To reduce measurement errors caused by line frequency noise or any other

environmental noise source, the 4155C/4156C takes some measurement samples

and averages them to obtain measurement data. The number of measurement

samples depends on the integration time. Setting a longer integration time increases

the number of measurement samples, so you can get more accurate measurement

data. The integration time setting is effective for the all measurement units.

For the sweep and sampling measurements, integration time is set in the INTEG

TIME field of the MEASURE: MEASURE SETUP screen, and selected by using

the Integ Time front-panel keys (

Long, Medium, and Short).

For the quasi-static CV measurements, integration time is the value set in the

INTEG TIME field of the MEASURE: QSCV MEASURE SETUP screen. The

Short, Medium, and Long front-panel keys have no effect for QSCV mode.

NOTE ADC Zero Function for Long/Medium

ADC zero function automatically works to cancel the offset of the ADC and extends

the integration time to double. This function is available for voltage measurements

or current measurements using the 10 nA range or greater. However, in FLEX

command control mode, you can disable this function by using the AZ command.

LONG Long mode is effective when you need high resolution and noise reduction

measurement, but the measurement is slow. To set long mode, press the

Long

front-panel key.

Initial setting 16 PLC

Integration time Available values: 2 PLC to 100 PLC with 1 PLC resolution

For the current measurements, the integration time is

automatically set as shown in Table 7-22.